StringUtils documentation

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org.apache.commons.lang

Class StringUtils

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public class StringUtils

Operations on String that are null safe.

IsEmpty/IsBlank - checks if a String contains text
Trim/Strip - removes leading and trailing whitespace
Equals - compares two strings null-safe
IndexOf/LastIndexOf/Contains - null-safe index-of checks
IndexOfAny/LastIndexOfAny/IndexOfAnyBut/LastIndexOfAnyBut - index-of any of a set of Strings
ContainsOnly/ContainsNone - does String contains only/none of these characters
Substring/Left/Right/Mid - null-safe substring extractions
SubstringBefore/SubstringAfter/SubstringBetween - substring extraction relative to other strings
Split/Join - splits a String into an array of substrings and vice versa
Remove/Delete - removes part of a String
Replace/Overlay - Searches a String and replaces one String with another
Chomp/Chop - removes the last part of a String
LeftPad/RightPad/Center/Repeat - pads a String
UpperCase/LowerCase/SwapCase/Capitalize/Uncapitalize - changes the case of a String
CountMatches - counts the number of occurrences of one String in another
IsAlpha/IsNumeric/IsWhitespace/IsAsciiPrintable - checks the characters in a String
DefaultString - protects against a null input String
Reverse/ReverseDelimited - reverses a String
Abbreviate - abbreviates a string using ellipsis
Difference - compares two Strings and reports on their differences
LevensteinDistance - the number of changes needed to change one String into another

The StringUtils class defines certain words related to String handling.

null - null
empty - a zero-length string ("")
space - the space character (' ', char 32)
whitespace - the characters defined by isWhitespace(char)
trim - the characters <= 32 as in trim()

StringUtils handles null input Strings quietly. That is to say that a null input will return null. Where a boolean or int is being returned details vary by method.

A side effect of the null handling is that a NullPointerException should be considered a bug in StringUtils (except for deprecated methods).

Methods in this class give sample code to explain their operation. The symbol * is used to indicate any input including null.

Since1.0

Version$Id: Strin

Author<a href="http://jakarta.apache.org/turbine/">Apache Jakarta Turbine</a>, GenerationJavaCore, <a href="mailto:jon@latchkey.com">Jon S. Stevens</a>, <a href="mailto:dlr@finemaltcoding.com">Daniel Rall</a>, <a href="mailto:gcoladonato@yahoo.com">Greg Coladon

See also

String

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Field Summary
static String	EMPTY The empty String `""`.
static int	INDEX_NOT_FOUND Represents a failed index search.

Constructor Summary
StringUtils() `StringUtils` instances should NOT be constructed in standard programming.

Method Summary
static String	abbreviate( String str, int maxWidth ) Abbreviates a String using ellipses.
static String	abbreviate( String str, int offset, int maxWidth ) Abbreviates a String using ellipses.
static String	capitalise( String str ) Capitalizes a String changing the first letter to title case as per toTitleCase(char) .
static String	capitaliseAllWords( String str ) Capitalizes all the whitespace separated words in a String.
static String	capitalize( String str ) Capitalizes a String changing the first letter to title case as per toTitleCase(char) .
static String	center( String str, int size ) Centers a String in a larger String of size `size` using the space character (' ').
static String	center( String str, int size, char padChar ) Centers a String in a larger String of size `size`.
static String	center( String str, int size, String padStr ) Centers a String in a larger String of size `size`.
static String	chomp( String str ) Removes one newline from end of a String if it's there, otherwise leave it alone.
static String	chomp( String str, String separator ) Removes `separator` from the end of `str` if it's there, otherwise leave it alone.
static String	chompLast( String str ) Remove any "\n" if and only if it is at the end of the supplied String.
static String	chompLast( String str, String sep ) Remove a value if and only if the String ends with that value.
static String	chop( String str ) Remove the last character from a String.
static String	chopNewline( String str ) Removes `\n` from end of a String if it's there.
static String	clean( String str ) Removes control characters (char <= 32) from both ends of this String, handling `null` by returning an empty String ("").
static String	concatenate( Object [] array ) Concatenates elements of an array into a single String.
static boolean	contains( String str, char searchChar ) Checks if String contains a search character, handling `null`.
static boolean	contains( String str, String searchStr ) Checks if String contains a search String, handling `null`.
static boolean	containsNone( String str, char [] invalidChars ) Checks that the String does not contain certain characters.
static boolean	containsNone( String str, String invalidChars ) Checks that the String does not contain certain characters.
static boolean	containsOnly( String str, char [] valid ) Checks if the String contains only certain characters.
static boolean	containsOnly( String str, String validChars ) Checks if the String contains only certain characters.
static int	countMatches( String str, String sub ) Counts how many times the substring appears in the larger String.
static String	defaultIfEmpty( String str, String defaultStr ) Returns either the passed in String, or if the String is empty or `null`, the value of `defaultStr`.
static String	defaultString( String str ) Returns either the passed in String, or if the String is `null`, an empty String ("").
static String	defaultString( String str, String defaultStr ) Returns either the passed in String, or if the String is `null`, the value of `defaultStr`.
static String	deleteSpaces( String str ) Deletes all 'space' characters from a String as defined by isSpace(char) .
static String	deleteWhitespace( String str ) Deletes all whitespaces from a String as defined by isWhitespace(char) .
static String	difference( String str1, String str2 ) Compares two Strings, and returns the portion where they differ.
static boolean	equals( String str1, String str2 ) Compares two Strings, returning `true` if they are equal.
static boolean	equalsIgnoreCase( String str1, String str2 ) Compares two Strings, returning `true` if they are equal ignoring the case.
static String	escape( String str ) Escapes any values it finds into their String form.
static String	getChomp( String str, String sep ) Remove everything and return the last value of a supplied String, and everything after it from a String.
static int	getLevenshteinDistance( String s, String t ) Find the Levenshtein distance between two Strings.
static String	getNestedString( String str, String tag ) Gets the String that is nested in between two instances of the same String.
static String	getNestedString( String str, String open, String close ) Gets the String that is nested in between two Strings.
static String	getPrechomp( String str, String sep ) Remove and return everything before the first value of a supplied String from another String.
static int	indexOf( String str, char searchChar ) Finds the first index within a String, handling `null`.
static int	indexOf( String str, char searchChar, int startPos ) Finds the first index within a String from a start position, handling `null`.
static int	indexOf( String str, String searchStr ) Finds the first index within a String, handling `null`.
static int	indexOf( String str, String searchStr, int startPos ) Finds the first index within a String, handling `null`.
static int	indexOfAny( String str, char [] searchChars ) Search a String to find the first index of any character in the given set of characters.
static int	indexOfAny( String str, String searchChars ) Search a String to find the first index of any character in the given set of characters.
static int	indexOfAny( String str, String [] searchStrs ) Find the first index of any of a set of potential substrings.
static int	indexOfAnyBut( String str, char [] searchChars ) Search a String to find the first index of any character not in the given set of characters.
static int	indexOfAnyBut( String str, String searchChars ) Search a String to find the first index of any character not in the given set of characters.
static int	indexOfDifference( String str1, String str2 ) Compares two Strings, and returns the index at which the Strings begin to differ.
static boolean	isAlpha( String str ) Checks if the String contains only unicode letters.
static boolean	isAlphanumeric( String str ) Checks if the String contains only unicode letters or digits.
static boolean	isAlphanumericSpace( String str ) Checks if the String contains only unicode letters, digits or space (`' '`).
static boolean	isAlphaSpace( String str ) Checks if the String contains only unicode letters and space (' ').
static boolean	isAsciiPrintable( String str ) Checks if the string contains only ASCII printable characters.
static boolean	isBlank( String str ) Checks if a String is whitespace, empty ("") or null.
static boolean	isEmpty( String str ) Checks if a String is empty ("") or null.
static boolean	isNotBlank( String str ) Checks if a String is not empty (""), not null and not whitespace only.
static boolean	isNotEmpty( String str ) Checks if a String is not empty ("") and not null.
static boolean	isNumeric( String str ) Checks if the String contains only unicode digits.
static boolean	isNumericSpace( String str ) Checks if the String contains only unicode digits or space (`' '`).
static boolean	isWhitespace( String str ) Checks if the String contains only whitespace.
static String	join( Object [] array ) Joins the elements of the provided array into a single String containing the provided list of elements.
static String	join( Object [] array, char separator ) Joins the elements of the provided array into a single String containing the provided list of elements.
static String	join( Object [] array, String separator ) Joins the elements of the provided array into a single String containing the provided list of elements.
static String	join( Iterator iterator, char separator ) Joins the elements of the provided `Iterator` into a single String containing the provided elements.
static String	join( Iterator iterator, String separator ) Joins the elements of the provided `Iterator` into a single String containing the provided elements.
static int	lastIndexOf( String str, char searchChar ) Finds the last index within a String, handling `null`.
static int	lastIndexOf( String str, char searchChar, int startPos ) Finds the last index within a String from a start position, handling `null`.
static int	lastIndexOf( String str, String searchStr ) Finds the last index within a String, handling `null`.
static int	lastIndexOf( String str, String searchStr, int startPos ) Finds the first index within a String, handling `null`.
static int	lastIndexOfAny( String str, String [] searchStrs ) Find the latest index of any of a set of potential substrings.
static String	left( String str, int len ) Gets the leftmost `len` characters of a String.
static String	leftPad( String str, int size ) Left pad a String with spaces (' ').
static String	leftPad( String str, int size, char padChar ) Left pad a String with a specified character.
static String	leftPad( String str, int size, String padStr ) Left pad a String with a specified String.
static String	lowerCase( String str ) Converts a String to lower case as per toLowerCase() .
static String	mid( String str, int pos, int len ) Gets `len` characters from the middle of a String.
static int	ordinalIndexOf( String str, String searchStr, int ordinal ) Finds the n-th index within a String, handling `null`.
static String	overlay( String str, String overlay, int start, int end ) Overlays part of a String with another String.
static String	overlayString( String text, String overlay, int start, int end ) Overlays part of a String with another String.
static String	prechomp( String str, String sep ) Remove the first value of a supplied String, and everything before it from a String.
static String	remove( String str, String remove ) Removes all occurances of a substring from within the source string.
static String	remove( String str, char remove ) Removes all occurances of a character from within the source string.
static String	removeEnd( String str, String remove ) Removes a substring only if it is at the end of a source string, otherwise returns the source string.
static String	removeStart( String str, String remove ) Removes a substring only if it is at the begining of a source string, otherwise returns the source string.
static String	repeat( String str, int repeat ) Repeat a String `repeat` times to form a new String.
static String	replace( String text, String repl, String with ) Replaces all occurrences of a String within another String.
static String	replace( String text, String repl, String with, int max ) Replaces a String with another String inside a larger String, for the first `max` values of the search String.
static String	replaceChars( String str, char searchChar, char replaceChar ) Replaces all occurrences of a character in a String with another.
static String	replaceChars( String str, String searchChars, String replaceChars ) Replaces multiple characters in a String in one go.
static String	replaceOnce( String text, String repl, String with ) Replaces a String with another String inside a larger String, once.
static String	reverse( String str ) Reverses a String as per reverse() .
static String	reverseDelimited( String str, char separatorChar ) Reverses a String that is delimited by a specific character.
static String	reverseDelimitedString( String str, String separatorChars ) Reverses a String that is delimited by a specific character.
static String	right( String str, int len ) Gets the rightmost `len` characters of a String.
static String	rightPad( String str, int size ) Right pad a String with spaces (' ').
static String	rightPad( String str, int size, char padChar ) Right pad a String with a specified character.
static String	rightPad( String str, int size, String padStr ) Right pad a String with a specified String.
static String[]	split( String str ) Splits the provided text into an array, using whitespace as the separator.
static String[]	split( String str, char separatorChar ) Splits the provided text into an array, separator specified.
static String[]	split( String str, String separatorChars ) Splits the provided text into an array, separators specified.
static String[]	split( String str, String separatorChars, int max ) Splits the provided text into an array with a maximum length, separators specified.
static String[]	splitByWholeSeparator( String str, String separator ) Splits the provided text into an array, separator string specified.
static String[]	splitByWholeSeparator( String str, String separator, int max ) Splits the provided text into an array, separator string specified.
static String[]	splitPreserveAllTokens( String str ) Splits the provided text into an array, using whitespace as the separator, preserving all tokens, including empty tokens created by adjacent separators.
static String[]	splitPreserveAllTokens( String str, char separatorChar ) Splits the provided text into an array, separator specified, preserving all tokens, including empty tokens created by adjacent separators.
static String[]	splitPreserveAllTokens( String str, String separatorChars ) Splits the provided text into an array, separators specified, preserving all tokens, including empty tokens created by adjacent separators.
static String[]	splitPreserveAllTokens( String str, String separatorChars, int max ) Splits the provided text into an array with a maximum length, separators specified, preserving all tokens, including empty tokens created by adjacent separators.
static String	strip( String str ) Strips whitespace from the start and end of a String.
static String	strip( String str, String stripChars ) Strips any of a set of characters from the start and end of a String.
static String[]	stripAll( String [] strs ) Strips whitespace from the start and end of every String in an array.
static String[]	stripAll( String [] strs, String stripChars ) Strips any of a set of characters from the start and end of every String in an array.
static String	stripEnd( String str, String stripChars ) Strips any of a set of characters from the end of a String.
static String	stripStart( String str, String stripChars ) Strips any of a set of characters from the start of a String.
static String	stripToEmpty( String str ) Strips whitespace from the start and end of a String returning an empty String if `null` input.
static String	stripToNull( String str ) Strips whitespace from the start and end of a String returning `null` if the String is empty ("") after the strip.
static String	substring( String str, int start ) Gets a substring from the specified String avoiding exceptions.
static String	substring( String str, int start, int end ) Gets a substring from the specified String avoiding exceptions.
static String	substringAfter( String str, String separator ) Gets the substring after the first occurrence of a separator.
static String	substringAfterLast( String str, String separator ) Gets the substring after the last occurrence of a separator.
static String	substringBefore( String str, String separator ) Gets the substring before the first occurrence of a separator.
static String	substringBeforeLast( String str, String separator ) Gets the substring before the last occurrence of a separator.
static String	substringBetween( String str, String tag ) Gets the String that is nested in between two instances of the same String.
static String	substringBetween( String str, String open, String close ) Gets the String that is nested in between two Strings.
static String	swapCase( String str ) Swaps the case of a String changing upper and title case to lower case, and lower case to upper case.
static String	trim( String str ) Removes control characters (char <= 32) from both ends of this String, handling `null` by returning `null`.
static String	trimToEmpty( String str ) Removes control characters (char <= 32) from both ends of this String returning an empty String ("") if the String is empty ("") after the trim or if it is `null`.
static String	trimToNull( String str ) Removes control characters (char <= 32) from both ends of this String returning `null` if the String is empty ("") after the trim or if it is `null`.
static String	uncapitalise( String str ) Uncapitalizes a String changing the first letter to title case as per toLowerCase(char) .
static String	uncapitalize( String str ) Uncapitalizes a String changing the first letter to title case as per toLowerCase(char) .
static String	upperCase( String str ) Converts a String to upper case as per toUpperCase() .

Methods inherited from java.langObject
clone () equals (Object) finalize () getClass () hashCode () notify () notifyAll () toString () wait (long, int) wait () wait (long)

Field Detail

EMPTY

public static String EMPTY

The empty String "".

Since: 2.0

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INDEX_NOT_FOUND

public static int INDEX_NOT_FOUND

Represents a failed index search.

Since: 2.1

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Constructor Detail

StringUtils

public StringUtils ( )

StringUtils instances should NOT be constructed in standard programming. Instead, the class should be used as StringUtils.trim(" foo ");.

This constructor is public to permit tools that require a JavaBean instance to operate.

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Method Detail

abbreviate

public static String abbreviate ( String str, int maxWidth )

Abbreviates a String using ellipses. This will turn "Now is the time for all good men" into "Now is the time for..."

Specifically:

If str is less than maxWidth characters long, return it.
Else abbreviate it to (substring(str, 0, max-3) + "...").
If maxWidth is less than 4, throw an IllegalArgumentException.
In no case will it return a String of length greater than maxWidth.

 StringUtils.abbreviate(null, *)      = null
 StringUtils.abbreviate("", 4)        = ""
 StringUtils.abbreviate("abcdefg", 6) = "abc..."
 StringUtils.abbreviate("abcdefg", 7) = "abcdefg"
 StringUtils.abbreviate("abcdefg", 8) = "abcdefg"
 StringUtils.abbreviate("abcdefg", 4) = "a..."
 StringUtils.abbreviate("abcdefg", 3) = IllegalArgumentException

Since: 2.0

Parameters

Type	Name	Description
String	str	the String to check, may be null
int	maxWidth	maximum length of result String, must be at least 4

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abbreviate

public static String abbreviate ( String str, int offset, int maxWidth )

Abbreviates a String using ellipses. This will turn "Now is the time for all good men" into "...is the time for..."

Works like abbreviate(String, int), but allows you to specify a "left edge" offset. Note that this left edge is not necessarily going to be the leftmost character in the result, or the first character following the ellipses, but it will appear somewhere in the result.

In no case will it return a String of length greater than maxWidth.

 StringUtils.abbreviate(null, *, *)                = null
 StringUtils.abbreviate("", 0, 4)                  = ""
 StringUtils.abbreviate("abcdefghijklmno", -1, 10) = "abcdefg..."
 StringUtils.abbreviate("abcdefghijklmno", 0, 10)  = "abcdefg..."
 StringUtils.abbreviate("abcdefghijklmno", 1, 10)  = "abcdefg..."
 StringUtils.abbreviate("abcdefghijklmno", 4, 10)  = "abcdefg..."
 StringUtils.abbreviate("abcdefghijklmno", 5, 10)  = "...fghi..."
 StringUtils.abbreviate("abcdefghijklmno", 6, 10)  = "...ghij..."
 StringUtils.abbreviate("abcdefghijklmno", 8, 10)  = "...ijklmno"
 StringUtils.abbreviate("abcdefghijklmno", 10, 10) = "...ijklmno"
 StringUtils.abbreviate("abcdefghijklmno", 12, 10) = "...ijklmno"
 StringUtils.abbreviate("abcdefghij", 0, 3)        = IllegalArgumentException
 StringUtils.abbreviate("abcdefghij", 5, 6)        = IllegalArgumentException

Since: 2.0

Parameters

Type	Name	Description
String	str	the String to check, may be null
int	offset	left edge of source String
int	maxWidth	maximum length of result String, must be at least 4

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capitalise

public static String capitalise ( String str )

Capitalizes a String changing the first letter to title case as per toTitleCase(char) . No other letters are changed.

Parameters

Type	Name	Description
String	str	the String to capitalize, may be null

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capitaliseAllWords

public static String capitaliseAllWords ( String str )

Capitalizes all the whitespace separated words in a String. Only the first letter of each word is changed.

Whitespace is defined by isWhitespace(char) . A null input String returns null.

Parameters

Type	Name	Description
String	str	the String to capitalize, may be null

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capitalize

public static String capitalize ( String str )

Capitalizes a String changing the first letter to title case as per toTitleCase(char) . No other letters are changed.

For a word based algorithm, see capitalize(String) . A null input String returns null.

 StringUtils.capitalize(null)  = null
 StringUtils.capitalize("")    = ""
 StringUtils.capitalize("cat") = "Cat"
 StringUtils.capitalize("cAt") = "CAt"

Since: 2.0

Parameters

Type	Name	Description
String	str	the String to capitalize, may be null

See also

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center

public static String center ( String str, int size )

Centers a String in a larger String of size size using the space character (' ').

If the size is less than the String length, the String is returned. A null String returns null. A negative size is treated as zero.

Equivalent to center(str, size, " ").

 StringUtils.center(null, *)   = null
 StringUtils.center("", 4)     = "    "
 StringUtils.center("ab", -1)  = "ab"
 StringUtils.center("ab", 4)   = " ab "
 StringUtils.center("abcd", 2) = "abcd"
 StringUtils.center("a", 4)    = " a  "

Parameters

Type	Name	Description
String	str	the String to center, may be null
int	size	the int size of new String, negative treated as zero

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center

public static String center ( String str, int size, char padChar )

Centers a String in a larger String of size size. Uses a supplied character as the value to pad the String with.

If the size is less than the String length, the String is returned. A null String returns null. A negative size is treated as zero.

 StringUtils.center(null, *, *)     = null
 StringUtils.center("", 4, ' ')     = "    "
 StringUtils.center("ab", -1, ' ')  = "ab"
 StringUtils.center("ab", 4, ' ')   = " ab"
 StringUtils.center("abcd", 2, ' ') = "abcd"
 StringUtils.center("a", 4, ' ')    = " a  "
 StringUtils.center("a", 4, 'y')    = "yayy"

Since: 2.0

Parameters

Type	Name	Description
String	str	the String to center, may be null
int	size	the int size of new String, negative treated as zero
char	padChar	the character to pad the new String with

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center

public static String center ( String str, int size, String padStr )

Centers a String in a larger String of size size. Uses a supplied String as the value to pad the String with.

If the size is less than the String length, the String is returned. A null String returns null. A negative size is treated as zero.

 StringUtils.center(null, *, *)     = null
 StringUtils.center("", 4, " ")     = "    "
 StringUtils.center("ab", -1, " ")  = "ab"
 StringUtils.center("ab", 4, " ")   = " ab"
 StringUtils.center("abcd", 2, " ") = "abcd"
 StringUtils.center("a", 4, " ")    = " a  "
 StringUtils.center("a", 4, "yz")   = "yayz"
 StringUtils.center("abc", 7, null) = "  abc  "
 StringUtils.center("abc", 7, "")   = "  abc  "

Parameters

Type	Name	Description
String	str	the String to center, may be null
int	size	the int size of new String, negative treated as zero
String	padStr	the String to pad the new String with, must not be null or empty

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chomp

public static String chomp ( String str )

Removes one newline from end of a String if it's there, otherwise leave it alone. A newline is "\n", "\r", or "\r\n".

NOTE: This method changed in 2.0. It now more closely matches Perl chomp.

 StringUtils.chomp(null)          = null
 StringUtils.chomp("")            = ""
 StringUtils.chomp("abc \r")      = "abc "
 StringUtils.chomp("abc\n")       = "abc"
 StringUtils.chomp("abc\r\n")     = "abc"
 StringUtils.chomp("abc\r\n\r\n") = "abc\r\n"
 StringUtils.chomp("abc\n\r")     = "abc\n"
 StringUtils.chomp("abc\n\rabc")  = "abc\n\rabc"
 StringUtils.chomp("\r")          = ""
 StringUtils.chomp("\n")          = ""
 StringUtils.chomp("\r\n")        = ""

Parameters

Type	Name	Description
String	str	the String to chomp a newline from, may be null

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chomp

public static String chomp ( String str, String separator )

Removes separator from the end of str if it's there, otherwise leave it alone.

NOTE: This method changed in version 2.0. It now more closely matches Perl chomp. For the previous behavior, use substringBeforeLast(String, String) . This method uses endsWith(String) .

 StringUtils.chomp(null, *)         = null
 StringUtils.chomp("", *)           = ""
 StringUtils.chomp("foobar", "bar") = "foo"
 StringUtils.chomp("foobar", "baz") = "foobar"
 StringUtils.chomp("foo", "foo")    = ""
 StringUtils.chomp("foo ", "foo")   = "foo "
 StringUtils.chomp(" foo", "foo")   = " "
 StringUtils.chomp("foo", "foooo")  = "foo"
 StringUtils.chomp("foo", "")       = "foo"
 StringUtils.chomp("foo", null)     = "foo"

Parameters

Type	Name	Description
String	str	the String to chomp from, may be null
String	separator	separator String, may be null

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chompLast

public static String chompLast ( String str )

Remove any "\n" if and only if it is at the end of the supplied String.

Parameters

Type	Name	Description
String	str	the String to chomp from, must not be null

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chompLast

public static String chompLast ( String str, String sep )

Remove a value if and only if the String ends with that value.

Parameters

Type	Name	Description
String	str	the String to chomp from, must not be null
String	sep	the String to chomp, must not be null

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chop

public static String chop ( String str )

Remove the last character from a String.

If the String ends in \r\n, then remove both of them.

 StringUtils.chop(null)          = null
 StringUtils.chop("")            = ""
 StringUtils.chop("abc \r")      = "abc "
 StringUtils.chop("abc\n")       = "abc"
 StringUtils.chop("abc\r\n")     = "abc"
 StringUtils.chop("abc")         = "ab"
 StringUtils.chop("abc\nabc")    = "abc\nab"
 StringUtils.chop("a")           = ""
 StringUtils.chop("\r")          = ""
 StringUtils.chop("\n")          = ""
 StringUtils.chop("\r\n")        = ""

Parameters

Type	Name	Description
String	str	the String to chop last character from, may be null

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chopNewline

public static String chopNewline ( String str )

Removes \n from end of a String if it's there. If a \r precedes it, then remove that too.

Parameters

Type	Name	Description
String	str	the String to chop a newline from, must not be null

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clean

public static String clean ( String str )

Removes control characters (char <= 32) from both ends of this String, handling null by returning an empty String ("").

 StringUtils.clean(null)          = ""
 StringUtils.clean("")            = ""
 StringUtils.clean("abc")         = "abc"
 StringUtils.clean("    abc    ") = "abc"
 StringUtils.clean("     ")       = ""

Parameters

Type	Name	Description
String	str	the String to clean, may be null

See also

trim()

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concatenate

public static String concatenate ( Object [] array )

Concatenates elements of an array into a single String. Null objects or empty strings within the array are represented by empty strings.

 StringUtils.concatenate(null)            = null
 StringUtils.concatenate([])              = ""
 StringUtils.concatenate([null])          = ""
 StringUtils.concatenate(["a", "b", "c"]) = "abc"
 StringUtils.concatenate([null, "", "a"]) = "a"

Parameters

Type	Name	Description
Object []	array	the array of values to concatenate, may be null

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contains

public static boolean contains ( String str, char searchChar )

Checks if String contains a search character, handling null. This method uses indexOf(int) .

A null or empty ("") String will return false.

 StringUtils.contains(null, *)    = false
 StringUtils.contains("", *)      = false
 StringUtils.contains("abc", 'a') = true
 StringUtils.contains("abc", 'z') = false

Since: 2.0

Parameters

Type	Name	Description
String	str	the String to check, may be null
char	searchChar	the character to find

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contains

public static boolean contains ( String str, String searchStr )

Checks if String contains a search String, handling null. This method uses indexOf(int) .

A null String will return false.

 StringUtils.contains(null, *)     = false
 StringUtils.contains(*, null)     = false
 StringUtils.contains("", "")      = true
 StringUtils.contains("abc", "")   = true
 StringUtils.contains("abc", "a")  = true
 StringUtils.contains("abc", "z")  = false

Since: 2.0

Parameters

Type	Name	Description
String	str	the String to check, may be null
String	searchStr	the String to find, may be null

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containsNone

public static boolean containsNone ( String str, char [] invalidChars )

Checks that the String does not contain certain characters.

A null String will return true. A null invalid character array will return true. An empty String ("") always returns true.

 StringUtils.containsNone(null, *)       = true
 StringUtils.containsNone(*, null)       = true
 StringUtils.containsNone("", *)         = true
 StringUtils.containsNone("ab", '')      = true
 StringUtils.containsNone("abab", 'xyz') = true
 StringUtils.containsNone("ab1", 'xyz')  = true
 StringUtils.containsNone("abz", 'xyz')  = false

Since: 2.0

Parameters

Type	Name	Description
String	str	the String to check, may be null
char[]	invalidChars	an array of invalid chars, may be null

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containsNone

public static boolean containsNone ( String str, String invalidChars )

Checks that the String does not contain certain characters.

A null String will return true. A null invalid character array will return true. An empty String ("") always returns true.

 StringUtils.containsNone(null, *)       = true
 StringUtils.containsNone(*, null)       = true
 StringUtils.containsNone("", *)         = true
 StringUtils.containsNone("ab", "")      = true
 StringUtils.containsNone("abab", "xyz") = true
 StringUtils.containsNone("ab1", "xyz")  = true
 StringUtils.containsNone("abz", "xyz")  = false

Since: 2.0

Parameters

Type	Name	Description
String	str	the String to check, may be null
String	invalidChars	a String of invalid chars, may be null

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containsOnly

public static boolean containsOnly ( String str, char [] valid )

Checks if the String contains only certain characters.

A null String will return false. A null valid character array will return false. An empty String ("") always returns true.

 StringUtils.containsOnly(null, *)       = false
 StringUtils.containsOnly(*, null)       = false
 StringUtils.containsOnly("", *)         = true
 StringUtils.containsOnly("ab", '')      = false
 StringUtils.containsOnly("abab", 'abc') = true
 StringUtils.containsOnly("ab1", 'abc')  = false
 StringUtils.containsOnly("abz", 'abc')  = false

Parameters

Type	Name	Description
String	str	the String to check, may be null
char[]	valid	an array of valid chars, may be null

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containsOnly

public static boolean containsOnly ( String str, String validChars )

Checks if the String contains only certain characters.

A null String will return false. A null valid character String will return false. An empty String ("") always returns true.

 StringUtils.containsOnly(null, *)       = false
 StringUtils.containsOnly(*, null)       = false
 StringUtils.containsOnly("", *)         = true
 StringUtils.containsOnly("ab", "")      = false
 StringUtils.containsOnly("abab", "abc") = true
 StringUtils.containsOnly("ab1", "abc")  = false
 StringUtils.containsOnly("abz", "abc")  = false

Since: 2.0

Parameters

Type	Name	Description
String	str	the String to check, may be null
String	validChars	a String of valid chars, may be null

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countMatches

public static int countMatches ( String str, String sub )

Counts how many times the substring appears in the larger String.

A null or empty ("") String input returns 0.

 StringUtils.countMatches(null, *)       = 0
 StringUtils.countMatches("", *)         = 0
 StringUtils.countMatches("abba", null)  = 0
 StringUtils.countMatches("abba", "")    = 0
 StringUtils.countMatches("abba", "a")   = 2
 StringUtils.countMatches("abba", "ab")  = 1
 StringUtils.countMatches("abba", "xxx") = 0

Parameters

Type	Name	Description
String	str	the String to check, may be null
String	sub	the substring to count, may be null

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defaultIfEmpty

public static String defaultIfEmpty ( String str, String defaultStr )

Returns either the passed in String, or if the String is empty or null, the value of defaultStr.

 StringUtils.defaultIfEmpty(null, "NULL")  = "NULL"
 StringUtils.defaultIfEmpty("", "NULL")    = "NULL"
 StringUtils.defaultIfEmpty("bat", "NULL") = "bat"

Parameters

Type	Name	Description
String	str	the String to check, may be null
String	defaultStr	the default String to return if the input is empty ("") or `null`, may be null

See also

defaultString(String, String)

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defaultString

public static String defaultString ( String str )

Returns either the passed in String, or if the String is null, an empty String ("").

 StringUtils.defaultString(null)  = ""
 StringUtils.defaultString("")    = ""
 StringUtils.defaultString("bat") = "bat"

Parameters

Type	Name	Description
String	str	the String to check, may be null

See also

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defaultString

public static String defaultString ( String str, String defaultStr )

Returns either the passed in String, or if the String is null, the value of defaultStr.

 StringUtils.defaultString(null, "NULL")  = "NULL"
 StringUtils.defaultString("", "NULL")    = ""
 StringUtils.defaultString("bat", "NULL") = "bat"

Parameters

Type	Name	Description
String	str	the String to check, may be null
String	defaultStr	the default String to return if the input is `null`, may be null

See also

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deleteSpaces

public static String deleteSpaces ( String str )

Deletes all 'space' characters from a String as defined by isSpace(char) .

This is the only StringUtils method that uses the isSpace definition. You are advised to use deleteWhitespace(String) instead as whitespace is much better localized.

 StringUtils.deleteSpaces(null)           = null
 StringUtils.deleteSpaces("")             = ""
 StringUtils.deleteSpaces("abc")          = "abc"
 StringUtils.deleteSpaces(" \t  abc \n ") = "abc"
 StringUtils.deleteSpaces("ab  c")        = "abc"
 StringUtils.deleteSpaces("a\nb\tc     ") = "abc"

Spaces are defined as {' ', '\t', '\r', '\n', '\b'} in line with the deprecated isSpace method.

Parameters

Type	Name	Description
String	str	the String to delete spaces from, may be null

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deleteWhitespace

public static String deleteWhitespace ( String str )

Deletes all whitespaces from a String as defined by isWhitespace(char) .

 StringUtils.deleteWhitespace(null)         = null
 StringUtils.deleteWhitespace("")           = ""
 StringUtils.deleteWhitespace("abc")        = "abc"
 StringUtils.deleteWhitespace("   ab  c  ") = "abc"

Parameters

Type	Name	Description
String	str	the String to delete whitespace from, may be null

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difference

public static String difference ( String str1, String str2 )

Compares two Strings, and returns the portion where they differ. (More precisely, return the remainder of the second String, starting from where it's different from the first.)

For example, difference("i am a machine", "i am a robot") -> "robot".

 StringUtils.difference(null, null) = null
 StringUtils.difference("", "") = ""
 StringUtils.difference("", "abc") = "abc"
 StringUtils.difference("abc", "") = ""
 StringUtils.difference("abc", "abc") = ""
 StringUtils.difference("ab", "abxyz") = "xyz"
 StringUtils.difference("abcde", "abxyz") = "xyz"
 StringUtils.difference("abcde", "xyz") = "xyz"

Since: 2.0

Parameters

Type	Name	Description
String	str1	the first String, may be null
String	str2	the second String, may be null

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equals

public static boolean equals ( String str1, String str2 )

Compares two Strings, returning true if they are equal.

nulls are handled without exceptions. Two null references are considered to be equal. The comparison is case sensitive.

 StringUtils.equals(null, null)   = true
 StringUtils.equals(null, "abc")  = false
 StringUtils.equals("abc", null)  = false
 StringUtils.equals("abc", "abc") = true
 StringUtils.equals("abc", "ABC") = false

Parameters

Type	Name	Description
String	str1	the first String, may be null
String	str2	the second String, may be null

See also

equals(Object)

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equalsIgnoreCase

public static boolean equalsIgnoreCase ( String str1, String str2 )

Compares two Strings, returning true if they are equal ignoring the case.

nulls are handled without exceptions. Two null references are considered equal. Comparison is case insensitive.

 StringUtils.equalsIgnoreCase(null, null)   = true
 StringUtils.equalsIgnoreCase(null, "abc")  = false
 StringUtils.equalsIgnoreCase("abc", null)  = false
 StringUtils.equalsIgnoreCase("abc", "abc") = true
 StringUtils.equalsIgnoreCase("abc", "ABC") = true

Parameters

Type	Name	Description
String	str1	the first String, may be null
String	str2	the second String, may be null

See also

equalsIgnoreCase(String)

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escape

public static String escape ( String str )

Escapes any values it finds into their String form.

So a tab becomes the characters '\\' and 't'.

As of Lang 2.0, this calls escapeJava(String) behind the scenes.

Parameters

Type	Name	Description
String	str	String to escape values in

See also

escapeJava(String)

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getChomp

public static String getChomp ( String str, String sep )

Remove everything and return the last value of a supplied String, and everything after it from a String.

Parameters

Type	Name	Description
String	str	the String to chomp from, must not be null
String	sep	the String to chomp, must not be null

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getLevenshteinDistance

public static int getLevenshteinDistance ( String s, String t )

Find the Levenshtein distance between two Strings.

This is the number of changes needed to change one String into another, where each change is a single character modification (deletion, insertion or substitution).

This implementation of the Levenshtein distance algorithm is from http://www.merriampark.com/ld.htm

 StringUtils.getLevenshteinDistance(null, *)             = IllegalArgumentException
 StringUtils.getLevenshteinDistance(*, null)             = IllegalArgumentException
 StringUtils.getLevenshteinDistance("","")               = 0
 StringUtils.getLevenshteinDistance("","a")              = 1
 StringUtils.getLevenshteinDistance("aaapppp", "")       = 7
 StringUtils.getLevenshteinDistance("frog", "fog")       = 1
 StringUtils.getLevenshteinDistance("fly", "ant")        = 3
 StringUtils.getLevenshteinDistance("elephant", "hippo") = 7
 StringUtils.getLevenshteinDistance("hippo", "elephant") = 7
 StringUtils.getLevenshteinDistance("hippo", "zzzzzzzz") = 8
 StringUtils.getLevenshteinDistance("hello", "hallo")    = 1

Parameters

Type	Name	Description
String	s	the first String, must not be null
String	t	the second String, must not be null

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getNestedString

public static String getNestedString ( String str, String tag )

Gets the String that is nested in between two instances of the same String.

A null input String returns null. A null tag returns null.

 StringUtils.getNestedString(null, *)            = null
 StringUtils.getNestedString("", "")             = ""
 StringUtils.getNestedString("", "tag")          = null
 StringUtils.getNestedString("tagabctag", null)  = null
 StringUtils.getNestedString("tagabctag", "")    = ""
 StringUtils.getNestedString("tagabctag", "tag") = "abc"

Parameters

Type	Name	Description
String	str	the String containing nested-string, may be null
String	tag	the String before and after nested-string, may be null

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getNestedString

public static String getNestedString ( String str, String open, String close )

Gets the String that is nested in between two Strings. Only the first match is returned.

A null input String returns null. A null open/close returns null (no match). An empty ("") open/close returns an empty string.

 StringUtils.getNestedString(null, *, *)          = null
 StringUtils.getNestedString("", "", "")          = ""
 StringUtils.getNestedString("", "", "tag")       = null
 StringUtils.getNestedString("", "tag", "tag")    = null
 StringUtils.getNestedString("yabcz", null, null) = null
 StringUtils.getNestedString("yabcz", "", "")     = ""
 StringUtils.getNestedString("yabcz", "y", "z")   = "abc"
 StringUtils.getNestedString("yabczyabcz", "y", "z")   = "abc"

Parameters

Type	Name	Description
String	str	the String containing nested-string, may be null
String	open	the String before nested-string, may be null
String	close	the String after nested-string, may be null

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getPrechomp

public static String getPrechomp ( String str, String sep )

Remove and return everything before the first value of a supplied String from another String.

Parameters

Type	Name	Description
String	str	the String to chomp from, must not be null
String	sep	the String to chomp, must not be null

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indexOf

public static int indexOf ( String str, char searchChar )

Finds the first index within a String, handling null. This method uses indexOf(int) .

A null or empty ("") String will return -1.

 StringUtils.indexOf(null, *)         = -1
 StringUtils.indexOf("", *)           = -1
 StringUtils.indexOf("aabaabaa", 'a') = 0
 StringUtils.indexOf("aabaabaa", 'b') = 2

Since: 2.0

Parameters

Type	Name	Description
String	str	the String to check, may be null
char	searchChar	the character to find

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indexOf

public static int indexOf ( String str, char searchChar, int startPos )

Finds the first index within a String from a start position, handling null. This method uses indexOf(int, int) .

A null or empty ("") String will return -1. A negative start position is treated as zero. A start position greater than the string length returns -1.

 StringUtils.indexOf(null, *, *)          = -1
 StringUtils.indexOf("", *, *)            = -1
 StringUtils.indexOf("aabaabaa", 'b', 0)  = 2
 StringUtils.indexOf("aabaabaa", 'b', 3)  = 5
 StringUtils.indexOf("aabaabaa", 'b', 9)  = -1
 StringUtils.indexOf("aabaabaa", 'b', -1) = 2

Since: 2.0

Parameters

Type	Name	Description
String	str	the String to check, may be null
char	searchChar	the character to find
int	startPos	the start position, negative treated as zero

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indexOf

public static int indexOf ( String str, String searchStr )

Finds the first index within a String, handling null. This method uses indexOf(String) .

A null String will return -1.

 StringUtils.indexOf(null, *)          = -1
 StringUtils.indexOf(*, null)          = -1
 StringUtils.indexOf("", "")           = 0
 StringUtils.indexOf("aabaabaa", "a")  = 0
 StringUtils.indexOf("aabaabaa", "b")  = 2
 StringUtils.indexOf("aabaabaa", "ab") = 1
 StringUtils.indexOf("aabaabaa", "")   = 0

Since: 2.0

Parameters

Type	Name	Description
String	str	the String to check, may be null
String	searchStr	the String to find, may be null

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indexOf

public static int indexOf ( String str, String searchStr, int startPos )

Finds the first index within a String, handling null. This method uses indexOf(String, int) .

A null String will return -1. A negative start position is treated as zero. An empty ("") search String always matches. A start position greater than the string length only matches an empty search String.

 StringUtils.indexOf(null, *, *)          = -1
 StringUtils.indexOf(*, null, *)          = -1
 StringUtils.indexOf("", "", 0)           = 0
 StringUtils.indexOf("aabaabaa", "a", 0)  = 0
 StringUtils.indexOf("aabaabaa", "b", 0)  = 2
 StringUtils.indexOf("aabaabaa", "ab", 0) = 1
 StringUtils.indexOf("aabaabaa", "b", 3)  = 5
 StringUtils.indexOf("aabaabaa", "b", 9)  = -1
 StringUtils.indexOf("aabaabaa", "b", -1) = 2
 StringUtils.indexOf("aabaabaa", "", 2)   = 2
 StringUtils.indexOf("abc", "", 9)        = 3

Since: 2.0

Parameters

Type	Name	Description
String	str	the String to check, may be null
String	searchStr	the String to find, may be null
int	startPos	the start position, negative treated as zero

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indexOfAny

public static int indexOfAny ( String str, char [] searchChars )

Search a String to find the first index of any character in the given set of characters.

A null String will return -1. A null or zero length search array will return -1.

 StringUtils.indexOfAny(null, *)                = -1
 StringUtils.indexOfAny("", *)                  = -1
 StringUtils.indexOfAny(*, null)                = -1
 StringUtils.indexOfAny(*, [])                  = -1
 StringUtils.indexOfAny("zzabyycdxx",['z','a']) = 0
 StringUtils.indexOfAny("zzabyycdxx",['b','y']) = 3
 StringUtils.indexOfAny("aba", ['z'])           = -1

Since: 2.0

Parameters

Type	Name	Description
String	str	the String to check, may be null
char[]	searchChars	the chars to search for, may be null

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indexOfAny

public static int indexOfAny ( String str, String searchChars )

Search a String to find the first index of any character in the given set of characters.

A null String will return -1. A null search string will return -1.

 StringUtils.indexOfAny(null, *)            = -1
 StringUtils.indexOfAny("", *)              = -1
 StringUtils.indexOfAny(*, null)            = -1
 StringUtils.indexOfAny(*, "")              = -1
 StringUtils.indexOfAny("zzabyycdxx", "za") = 0
 StringUtils.indexOfAny("zzabyycdxx", "by") = 3
 StringUtils.indexOfAny("aba","z")          = -1

Since: 2.0

Parameters

Type	Name	Description
String	str	the String to check, may be null
String	searchChars	the chars to search for, may be null

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indexOfAny

public static int indexOfAny ( String str, String [] searchStrs )

Find the first index of any of a set of potential substrings.

A null String will return -1. A null or zero length search array will return -1. A null search array entry will be ignored, but a search array containing "" will return 0 if str is not null. This method uses indexOf(String) .

 StringUtils.indexOfAny(null, *)                     = -1
 StringUtils.indexOfAny(*, null)                     = -1
 StringUtils.indexOfAny(*, [])                       = -1
 StringUtils.indexOfAny("zzabyycdxx", ["ab","cd"])   = 2
 StringUtils.indexOfAny("zzabyycdxx", ["cd","ab"])   = 2
 StringUtils.indexOfAny("zzabyycdxx", ["mn","op"])   = -1
 StringUtils.indexOfAny("zzabyycdxx", ["zab","aby"]) = 1
 StringUtils.indexOfAny("zzabyycdxx", [""])          = 0
 StringUtils.indexOfAny("", [""])                    = 0
 StringUtils.indexOfAny("", ["a"])                   = -1

Parameters

Type	Name	Description
String	str	the String to check, may be null
String []	searchStrs	the Strings to search for, may be null

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indexOfAnyBut

public static int indexOfAnyBut ( String str, char [] searchChars )

Search a String to find the first index of any character not in the given set of characters.

A null String will return -1. A null or zero length search array will return -1.

 StringUtils.indexOfAnyBut(null, *)           = -1
 StringUtils.indexOfAnyBut("", *)             = -1
 StringUtils.indexOfAnyBut(*, null)           = -1
 StringUtils.indexOfAnyBut(*, [])             = -1
 StringUtils.indexOfAnyBut("zzabyycdxx",'za') = 3
 StringUtils.indexOfAnyBut("zzabyycdxx", '')  = 0
 StringUtils.indexOfAnyBut("aba", 'ab')       = -1

Since: 2.0

Parameters

Type	Name	Description
String	str	the String to check, may be null
char[]	searchChars	the chars to search for, may be null

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indexOfAnyBut

public static int indexOfAnyBut ( String str, String searchChars )

Search a String to find the first index of any character not in the given set of characters.

A null String will return -1. A null search string will return -1.

 StringUtils.indexOfAnyBut(null, *)            = -1
 StringUtils.indexOfAnyBut("", *)              = -1
 StringUtils.indexOfAnyBut(*, null)            = -1
 StringUtils.indexOfAnyBut(*, "")              = -1
 StringUtils.indexOfAnyBut("zzabyycdxx", "za") = 3
 StringUtils.indexOfAnyBut("zzabyycdxx", "")   = 0
 StringUtils.indexOfAnyBut("aba","ab")         = -1

Since: 2.0

Parameters

Type	Name	Description
String	str	the String to check, may be null
String	searchChars	the chars to search for, may be null

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indexOfDifference

public static int indexOfDifference ( String str1, String str2 )

Compares two Strings, and returns the index at which the Strings begin to differ.

For example, indexOfDifference("i am a machine", "i am a robot") -> 7

 StringUtils.indexOfDifference(null, null) = -1
 StringUtils.indexOfDifference("", "") = -1
 StringUtils.indexOfDifference("", "abc") = 0
 StringUtils.indexOfDifference("abc", "") = 0
 StringUtils.indexOfDifference("abc", "abc") = -1
 StringUtils.indexOfDifference("ab", "abxyz") = 2
 StringUtils.indexOfDifference("abcde", "abxyz") = 2
 StringUtils.indexOfDifference("abcde", "xyz") = 0

Since: 2.0

Parameters

Type	Name	Description
String	str1	the first String, may be null
String	str2	the second String, may be null

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isAlpha

public static boolean isAlpha ( String str )

Checks if the String contains only unicode letters.

null will return false. An empty String ("") will return true.

 StringUtils.isAlpha(null)   = false
 StringUtils.isAlpha("")     = true
 StringUtils.isAlpha("  ")   = false
 StringUtils.isAlpha("abc")  = true
 StringUtils.isAlpha("ab2c") = false
 StringUtils.isAlpha("ab-c") = false

Parameters

Type	Name	Description
String	str	the String to check, may be null

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isAlphanumeric

public static boolean isAlphanumeric ( String str )

Checks if the String contains only unicode letters or digits.

null will return false. An empty String ("") will return true.

 StringUtils.isAlphanumeric(null)   = false
 StringUtils.isAlphanumeric("")     = true
 StringUtils.isAlphanumeric("  ")   = false
 StringUtils.isAlphanumeric("abc")  = true
 StringUtils.isAlphanumeric("ab c") = false
 StringUtils.isAlphanumeric("ab2c") = true
 StringUtils.isAlphanumeric("ab-c") = false

Parameters

Type	Name	Description
String	str	the String to check, may be null

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isAlphanumericSpace

public static boolean isAlphanumericSpace ( String str )

Checks if the String contains only unicode letters, digits or space (' ').

null will return false. An empty String ("") will return true.

 StringUtils.isAlphanumeric(null)   = false
 StringUtils.isAlphanumeric("")     = true
 StringUtils.isAlphanumeric("  ")   = true
 StringUtils.isAlphanumeric("abc")  = true
 StringUtils.isAlphanumeric("ab c") = true
 StringUtils.isAlphanumeric("ab2c") = true
 StringUtils.isAlphanumeric("ab-c") = false

Parameters

Type	Name	Description
String	str	the String to check, may be null

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isAlphaSpace

public static boolean isAlphaSpace ( String str )

Checks if the String contains only unicode letters and space (' ').

null will return false An empty String ("") will return true.

 StringUtils.isAlphaSpace(null)   = false
 StringUtils.isAlphaSpace("")     = true
 StringUtils.isAlphaSpace("  ")   = true
 StringUtils.isAlphaSpace("abc")  = true
 StringUtils.isAlphaSpace("ab c") = true
 StringUtils.isAlphaSpace("ab2c") = false
 StringUtils.isAlphaSpace("ab-c") = false

Parameters

Type	Name	Description
String	str	the String to check, may be null

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isAsciiPrintable

public static boolean isAsciiPrintable ( String str )

Checks if the string contains only ASCII printable characters.

null will return false. An empty String ("") will return true.

 StringUtils.isAsciiPrintable(null)     = false
 StringUtils.isAsciiPrintable("")       = true
 StringUtils.isAsciiPrintable(" ")      = true
 StringUtils.isAsciiPrintable("Ceki")   = true
 StringUtils.isAsciiPrintable("ab2c")   = true
 StringUtils.isAsciiPrintable("!ab-c~") = true
 StringUtils.isAsciiPrintable(" ") = true
 StringUtils.isAsciiPrintable("!") = true
 StringUtils.isAsciiPrintable("~") = true
 StringUtils.isAsciiPrintable("") = false
 StringUtils.isAsciiPrintable("Ceki Gülcü") = false

Since: 2.1

Parameters

Type	Name	Description
String	str	the string to check, may be null

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isBlank

public static boolean isBlank ( String str )

Checks if a String is whitespace, empty ("") or null.

 StringUtils.isBlank(null)      = true
 StringUtils.isBlank("")        = true
 StringUtils.isBlank(" ")       = true
 StringUtils.isBlank("bob")     = false
 StringUtils.isBlank("  bob  ") = false

Since: 2.0

Parameters

Type	Name	Description
String	str	the String to check, may be null

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isEmpty

public static boolean isEmpty ( String str )

Checks if a String is empty ("") or null.

 StringUtils.isEmpty(null)      = true
 StringUtils.isEmpty("")        = true
 StringUtils.isEmpty(" ")       = false
 StringUtils.isEmpty("bob")     = false
 StringUtils.isEmpty("  bob  ") = false

NOTE: This method changed in Lang version 2.0. It no longer trims the String. That functionality is available in isBlank().

Parameters

Type	Name	Description
String	str	the String to check, may be null

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isNotBlank

public static boolean isNotBlank ( String str )

Checks if a String is not empty (""), not null and not whitespace only.

 StringUtils.isNotBlank(null)      = false
 StringUtils.isNotBlank("")        = false
 StringUtils.isNotBlank(" ")       = false
 StringUtils.isNotBlank("bob")     = true
 StringUtils.isNotBlank("  bob  ") = true

Since: 2.0

Parameters

Type	Name	Description
String	str	the String to check, may be null

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isNotEmpty

public static boolean isNotEmpty ( String str )

Checks if a String is not empty ("") and not null.

 StringUtils.isNotEmpty(null)      = false
 StringUtils.isNotEmpty("")        = false
 StringUtils.isNotEmpty(" ")       = true
 StringUtils.isNotEmpty("bob")     = true
 StringUtils.isNotEmpty("  bob  ") = true

Parameters

Type	Name	Description
String	str	the String to check, may be null

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isNumeric

public static boolean isNumeric ( String str )

Checks if the String contains only unicode digits. A decimal point is not a unicode digit and returns false.

null will return false. An empty String ("") will return true.

 StringUtils.isNumeric(null)   = false
 StringUtils.isNumeric("")     = true
 StringUtils.isNumeric("  ")   = false
 StringUtils.isNumeric("123")  = true
 StringUtils.isNumeric("12 3") = false
 StringUtils.isNumeric("ab2c") = false
 StringUtils.isNumeric("12-3") = false
 StringUtils.isNumeric("12.3") = false

Parameters

Type	Name	Description
String	str	the String to check, may be null

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isNumericSpace

public static boolean isNumericSpace ( String str )

Checks if the String contains only unicode digits or space (' '). A decimal point is not a unicode digit and returns false.

null will return false. An empty String ("") will return true.

 StringUtils.isNumeric(null)   = false
 StringUtils.isNumeric("")     = true
 StringUtils.isNumeric("  ")   = true
 StringUtils.isNumeric("123")  = true
 StringUtils.isNumeric("12 3") = true
 StringUtils.isNumeric("ab2c") = false
 StringUtils.isNumeric("12-3") = false
 StringUtils.isNumeric("12.3") = false

Parameters

Type	Name	Description
String	str	the String to check, may be null

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isWhitespace

public static boolean isWhitespace ( String str )

Checks if the String contains only whitespace.

null will return false. An empty String ("") will return true.

 StringUtils.isWhitespace(null)   = false
 StringUtils.isWhitespace("")     = true
 StringUtils.isWhitespace("  ")   = true
 StringUtils.isWhitespace("abc")  = false
 StringUtils.isWhitespace("ab2c") = false
 StringUtils.isWhitespace("ab-c") = false

Since: 2.0

Parameters

Type	Name	Description
String	str	the String to check, may be null

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join

public static String join ( Object [] array )

Joins the elements of the provided array into a single String containing the provided list of elements.

No separator is added to the joined String. Null objects or empty strings within the array are represented by empty strings.

 StringUtils.join(null)            = null
 StringUtils.join([])              = ""
 StringUtils.join([null])          = ""
 StringUtils.join(["a", "b", "c"]) = "abc"
 StringUtils.join([null, "", "a"]) = "a"

Since: 2.0

Parameters

Type	Name	Description
Object []	array	the array of values to join together, may be null

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join

public static String join ( Object [] array, char separator )

Joins the elements of the provided array into a single String containing the provided list of elements.

No delimiter is added before or after the list. Null objects or empty strings within the array are represented by empty strings.

 StringUtils.join(null, *)               = null
 StringUtils.join([], *)                 = ""
 StringUtils.join([null], *)             = ""
 StringUtils.join(["a", "b", "c"], ';')  = "a;b;c"
 StringUtils.join(["a", "b", "c"], null) = "abc"
 StringUtils.join([null, "", "a"], ';')  = ";;a"

Since: 2.0

Parameters

Type	Name	Description
Object []	array	the array of values to join together, may be null
char	separator	the separator character to use

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join

public static String join ( Object [] array, String separator )

Joins the elements of the provided array into a single String containing the provided list of elements.

No delimiter is added before or after the list. A null separator is the same as an empty String (""). Null objects or empty strings within the array are represented by empty strings.

 StringUtils.join(null, *)                = null
 StringUtils.join([], *)                  = ""
 StringUtils.join([null], *)              = ""
 StringUtils.join(["a", "b", "c"], "--")  = "a--b--c"
 StringUtils.join(["a", "b", "c"], null)  = "abc"
 StringUtils.join(["a", "b", "c"], "")    = "abc"
 StringUtils.join([null, "", "a"], ',')   = ",,a"

Parameters

Type	Name	Description
Object []	array	the array of values to join together, may be null
String	separator	the separator character to use, null treated as ""

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join

public static String join ( Iterator iterator, char separator )

Joins the elements of the provided Iterator into a single String containing the provided elements.

No delimiter is added before or after the list. Null objects or empty strings within the iteration are represented by empty strings.

See the examples here: join(Object[], char) .

Since: 2.0

Parameters

Type	Name	Description
Iterator	iterator	the `Iterator` of values to join together, may be null
char	separator	the separator character to use

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join

public static String join ( Iterator iterator, String separator )

Joins the elements of the provided Iterator into a single String containing the provided elements.

No delimiter is added before or after the list. A null separator is the same as an empty String ("").

See the examples here: join(Object[], String) .

Parameters

Type	Name	Description
Iterator	iterator	the `Iterator` of values to join together, may be null
String	separator	the separator character to use, null treated as ""

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lastIndexOf

public static int lastIndexOf ( String str, char searchChar )

Finds the last index within a String, handling null. This method uses lastIndexOf(int) .

A null or empty ("") String will return -1.

 StringUtils.lastIndexOf(null, *)         = -1
 StringUtils.lastIndexOf("", *)           = -1
 StringUtils.lastIndexOf("aabaabaa", 'a') = 7
 StringUtils.lastIndexOf("aabaabaa", 'b') = 5

Since: 2.0

Parameters

Type	Name	Description
String	str	the String to check, may be null
char	searchChar	the character to find

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lastIndexOf

public static int lastIndexOf ( String str, char searchChar, int startPos )

Finds the last index within a String from a start position, handling null. This method uses lastIndexOf(int, int) .

A null or empty ("") String will return -1. A negative start position returns -1. A start position greater than the string length searches the whole string.

 StringUtils.lastIndexOf(null, *, *)          = -1
 StringUtils.lastIndexOf("", *,  *)           = -1
 StringUtils.lastIndexOf("aabaabaa", 'b', 8)  = 5
 StringUtils.lastIndexOf("aabaabaa", 'b', 4)  = 2
 StringUtils.lastIndexOf("aabaabaa", 'b', 0)  = -1
 StringUtils.lastIndexOf("aabaabaa", 'b', 9)  = 5
 StringUtils.lastIndexOf("aabaabaa", 'b', -1) = -1
 StringUtils.lastIndexOf("aabaabaa", 'a', 0)  = 0

Since: 2.0

Parameters

Type	Name	Description
String	str	the String to check, may be null
char	searchChar	the character to find
int	startPos	the start position

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lastIndexOf

public static int lastIndexOf ( String str, String searchStr )

Finds the last index within a String, handling null. This method uses lastIndexOf(String) .

A null String will return -1.

 StringUtils.lastIndexOf(null, *)          = -1
 StringUtils.lastIndexOf(*, null)          = -1
 StringUtils.lastIndexOf("", "")           = 0
 StringUtils.lastIndexOf("aabaabaa", "a")  = 0
 StringUtils.lastIndexOf("aabaabaa", "b")  = 2
 StringUtils.lastIndexOf("aabaabaa", "ab") = 1
 StringUtils.lastIndexOf("aabaabaa", "")   = 8

Since: 2.0

Parameters

Type	Name	Description
String	str	the String to check, may be null
String	searchStr	the String to find, may be null

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lastIndexOf

public static int lastIndexOf ( String str, String searchStr, int startPos )

Finds the first index within a String, handling null. This method uses lastIndexOf(String, int) .

A null String will return -1. A negative start position returns -1. An empty ("") search String always matches unless the start position is negative. A start position greater than the string length searches the whole string.

 StringUtils.lastIndexOf(null, *, *)          = -1
 StringUtils.lastIndexOf(*, null, *)          = -1
 StringUtils.lastIndexOf("aabaabaa", "a", 8)  = 7
 StringUtils.lastIndexOf("aabaabaa", "b", 8)  = 5
 StringUtils.lastIndexOf("aabaabaa", "ab", 8) = 4
 StringUtils.lastIndexOf("aabaabaa", "b", 9)  = 5
 StringUtils.lastIndexOf("aabaabaa", "b", -1) = -1
 StringUtils.lastIndexOf("aabaabaa", "a", 0)  = 0
 StringUtils.lastIndexOf("aabaabaa", "b", 0)  = -1

Since: 2.0

Parameters

Type	Name	Description
String	str	the String to check, may be null
String	searchStr	the String to find, may be null
int	startPos	the start position, negative treated as zero

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lastIndexOfAny

public static int lastIndexOfAny ( String str, String [] searchStrs )

Find the latest index of any of a set of potential substrings.

A null String will return -1. A null search array will return -1. A null or zero length search array entry will be ignored, but a search array containing "" will return the length of str if str is not null. This method uses indexOf(String)

 StringUtils.lastIndexOfAny(null, *)                   = -1
 StringUtils.lastIndexOfAny(*, null)                   = -1
 StringUtils.lastIndexOfAny(*, [])                     = -1
 StringUtils.lastIndexOfAny(*, [null])                 = -1
 StringUtils.lastIndexOfAny("zzabyycdxx", ["ab","cd"]) = 6
 StringUtils.lastIndexOfAny("zzabyycdxx", ["cd","ab"]) = 6
 StringUtils.lastIndexOfAny("zzabyycdxx", ["mn","op"]) = -1
 StringUtils.lastIndexOfAny("zzabyycdxx", ["mn","op"]) = -1
 StringUtils.lastIndexOfAny("zzabyycdxx", ["mn",""])   = 10

Parameters

Type	Name	Description
String	str	the String to check, may be null
String []	searchStrs	the Strings to search for, may be null

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left

public static String left ( String str, int len )

Gets the leftmost len characters of a String.

If len characters are not available, or the String is null, the String will be returned without an exception. An exception is thrown if len is negative.

 StringUtils.left(null, *)    = null
 StringUtils.left(*, -ve)     = ""
 StringUtils.left("", *)      = ""
 StringUtils.left("abc", 0)   = ""
 StringUtils.left("abc", 2)   = "ab"
 StringUtils.left("abc", 4)   = "abc"

Parameters

Type	Name	Description
String	str	the String to get the leftmost characters from, may be null
int	len	the length of the required String, must be zero or positive

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leftPad

public static String leftPad ( String str, int size )

Left pad a String with spaces (' ').

The String is padded to the size of size.



  StringUtils.leftPad(null, *)   = null
 StringUtils.leftPad("", 3)     = "   "
 StringUtils.leftPad("bat", 3)  = "bat"
 StringUtils.leftPad("bat", 5)  = "  bat"
 StringUtils.leftPad("bat", 1)  = "bat"
 StringUtils.leftPad("bat", -1) = "bat"


	                
	                
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to pad out, may be null
				
	
                    

int

 
                    size
                    the size to pad to
				
 
    




 

	
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 leftPad
                
 public static     

String

leftPad
(




String



str,



int



size,



char



padChar
)

                
	                
Left pad a String with a specified character.

 Pad to a size of size.

  StringUtils.leftPad(null, *, *)     = null
 StringUtils.leftPad("", 3, 'z')     = "zzz"
 StringUtils.leftPad("bat", 3, 'z')  = "bat"
 StringUtils.leftPad("bat", 5, 'z')  = "zzbat"
 StringUtils.leftPad("bat", 1, 'z')  = "bat"
 StringUtils.leftPad("bat", -1, 'z') = "bat"
 
 
	                
	                
 
		                        Since: 2.0 
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to pad out, may be null
				
	
                    

int

 
                    size
                    the size to pad to
				
	
                    

char

 
                    padChar
                    the character to pad with
				
 
    




 

	
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 leftPad
                
 public static     

String

leftPad
(




String



str,



int



size,




String



padStr
)

                
	                
Left pad a String with a specified String.

 Pad to a size of size.

  StringUtils.leftPad(null, *, *)      = null
 StringUtils.leftPad("", 3, "z")      = "zzz"
 StringUtils.leftPad("bat", 3, "yz")  = "bat"
 StringUtils.leftPad("bat", 5, "yz")  = "yzbat"
 StringUtils.leftPad("bat", 8, "yz")  = "yzyzybat"
 StringUtils.leftPad("bat", 1, "yz")  = "bat"
 StringUtils.leftPad("bat", -1, "yz") = "bat"
 StringUtils.leftPad("bat", 5, null)  = "  bat"
 StringUtils.leftPad("bat", 5, "")    = "  bat"
 
 
	                
	                
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to pad out, may be null
				
	
                    

int

 
                    size
                    the size to pad to
				
	
                    


String

 
                    padStr
                    the String to pad with, null or empty treated as single space
				
 
    




 

	
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 lowerCase
                
 public static     

String

lowerCase
(




String



str
)

                
	                
Converts a String to lower case as per  toLowerCase() .

 A null input String returns null.

  StringUtils.lowerCase(null)  = null
 StringUtils.lowerCase("")    = ""
 StringUtils.lowerCase("aBc") = "abc"
 
 
	                
	                
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to lower case, may be null
				
 
    




 

	
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 mid
                
 public static     

String

mid
(




String



str,



int



pos,



int



len
)

                
	                
Gets len characters from the middle of a String.

 If len characters are not available, the remainder
 of the String will be returned without an exception. If the
 String is null, null will be returned.
 An exception is thrown if len is negative.

  StringUtils.mid(null, *, *)    = null
 StringUtils.mid(*, *, -ve)     = ""
 StringUtils.mid("", 0, *)      = ""
 StringUtils.mid("abc", 0, 2)   = "ab"
 StringUtils.mid("abc", 0, 4)   = "abc"
 StringUtils.mid("abc", 2, 4)   = "c"
 StringUtils.mid("abc", 4, 2)   = ""
 StringUtils.mid("abc", -2, 2)  = "ab"
 
 
	                
	                
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to get the characters from, may be null
				
	
                    

int

 
                    pos
                    the position to start from, negative treated as zero
				
	
                    

int

 
                    len
                    the length of the required String, must be zero or positive
				
 
    




 

	
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 ordinalIndexOf
                
 public static     
int


ordinalIndexOf
(




String



str,




String



searchStr,



int



ordinal
)

                
	                
Finds the n-th index within a String, handling null.
 This method uses  indexOf(String) .

 A null String will return -1.

  StringUtils.ordinalIndexOf(null, *, *)          = -1
 StringUtils.ordinalIndexOf(*, null, *)          = -1
 StringUtils.ordinalIndexOf("", "", *)           = 0
 StringUtils.ordinalIndexOf("aabaabaa", "a", 1)  = 0
 StringUtils.ordinalIndexOf("aabaabaa", "a", 2)  = 1
 StringUtils.ordinalIndexOf("aabaabaa", "b", 1)  = 2
 StringUtils.ordinalIndexOf("aabaabaa", "b", 2)  = 5
 StringUtils.ordinalIndexOf("aabaabaa", "ab", 1) = 1
 StringUtils.ordinalIndexOf("aabaabaa", "ab", 2) = 4
 StringUtils.ordinalIndexOf("aabaabaa", "", 1)   = 0
 StringUtils.ordinalIndexOf("aabaabaa", "", 2)   = 0
 
 
	                
	                
 
		                        Since: 2.1 
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to check, may be null
				
	
                    


String

 
                    searchStr
                    the String to find, may be null
				
	
                    

int

 
                    ordinal
                    the n-th searchStr to find
				
 
    




 

	
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 overlay
                
 public static     

String

overlay
(




String



str,




String



overlay,



int



start,



int



end
)

                
	                
Overlays part of a String with another String.

 A null string input returns null.
 A negative index is treated as zero.
 An index greater than the string length is treated as the string length.
 The start index is always the smaller of the two indices.

  StringUtils.overlay(null, *, *, *)            = null
 StringUtils.overlay("", "abc", 0, 0)          = "abc"
 StringUtils.overlay("abcdef", null, 2, 4)     = "abef"
 StringUtils.overlay("abcdef", "", 2, 4)       = "abef"
 StringUtils.overlay("abcdef", "", 4, 2)       = "abef"
 StringUtils.overlay("abcdef", "zzzz", 2, 4)   = "abzzzzef"
 StringUtils.overlay("abcdef", "zzzz", 4, 2)   = "abzzzzef"
 StringUtils.overlay("abcdef", "zzzz", -1, 4)  = "zzzzef"
 StringUtils.overlay("abcdef", "zzzz", 2, 8)   = "abzzzz"
 StringUtils.overlay("abcdef", "zzzz", -2, -3) = "zzzzabcdef"
 StringUtils.overlay("abcdef", "zzzz", 8, 10)  = "abcdefzzzz"
 
 
	                
	                
 
		                        Since: 2.0 
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to do overlaying in, may be null
				
	
                    


String

 
                    overlay
                    the String to overlay, may be null
				
	
                    

int

 
                    start
                    the position to start overlaying at
				
	
                    

int

 
                    end
                    the position to stop overlaying before
				
 
    




 

	
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 overlayString
                
 public static     

String

overlayString
(




String



text,




String



overlay,



int



start,



int



end
)

                
	                
Overlays part of a String with another String.

  StringUtils.overlayString(null, *, *, *)           = NullPointerException
 StringUtils.overlayString(*, null, *, *)           = NullPointerException
 StringUtils.overlayString("", "abc", 0, 0)         = "abc"
 StringUtils.overlayString("abcdef", null, 2, 4)    = "abef"
 StringUtils.overlayString("abcdef", "", 2, 4)      = "abef"
 StringUtils.overlayString("abcdef", "zzzz", 2, 4)  = "abzzzzef"
 StringUtils.overlayString("abcdef", "zzzz", 4, 2)  = "abcdzzzzcdef"
 StringUtils.overlayString("abcdef", "zzzz", -1, 4) = IndexOutOfBoundsException
 StringUtils.overlayString("abcdef", "zzzz", 2, 8)  = IndexOutOfBoundsException
 
 
	                
	                
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    text
                    the String to do overlaying in, may be null
				
	
                    


String

 
                    overlay
                    the String to overlay, may be null
				
	
                    

int

 
                    start
                    the position to start overlaying at, must be valid
				
	
                    

int

 
                    end
                    the position to stop overlaying before, must be valid
				
 
    




 

	
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 prechomp
                
 public static     

String

prechomp
(




String



str,




String



sep
)

                
	                
Remove the first value of a supplied String, and everything before it
 from a String.
 
	                
	                
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to chomp from, must not be null
				
	
                    


String

 
                    sep
                    the String to chomp, must not be null
				
 
    




 

	
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 remove
                
 public static     

String

remove
(




String



str,




String



remove
)

                
	                
Removes all occurances of a substring from within the source string.

 A null source string will return null.
 An empty ("") source string will return the empty string.
 A null remove string will return the source string.
 An empty ("") remove string will return the source string.

  StringUtils.remove(null, *)        = null
 StringUtils.remove("", *)          = ""
 StringUtils.remove(*, null)        = *
 StringUtils.remove(*, "")          = *
 StringUtils.remove("queued", "ue") = "qd"
 StringUtils.remove("queued", "zz") = "queued"
 
 
	                
	                
 
		                        Since: 2.1 
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the source String to search, may be null
				
	
                    


String

 
                    remove
                    the String to search for and remove, may be null
				
 
    




 

	
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 remove
                
 public static     

String

remove
(




String



str,



char



remove
)

                
	                
Removes all occurances of a character from within the source string.

 A null source string will return null.
 An empty ("") source string will return the empty string.

  StringUtils.remove(null, *)       = null
 StringUtils.remove("", *)         = ""
 StringUtils.remove("queued", 'u') = "qeed"
 StringUtils.remove("queued", 'z') = "queued"
 
 
	                
	                
 
		                        Since: 2.1 
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the source String to search, may be null
				
	
                    

char

 
                    remove
                    the char to search for and remove, may be null
				
 
    




 

	
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 removeEnd
                
 public static     

String

removeEnd
(




String



str,




String



remove
)

                
	                
Removes a substring only if it is at the end of a source string,
 otherwise returns the source string.

 A null source string will return null.
 An empty ("") source string will return the empty string.
 A null search string will return the source string.

  StringUtils.removeEnd(null, *)      = null
 StringUtils.removeEnd("", *)        = ""
 StringUtils.removeEnd(*, null)      = *
 StringUtils.removeEnd("www.domain.com", ".com.")  = "www,domain"
 StringUtils.removeEnd("www.domain.com", ".com")   = "www.domain"
 StringUtils.removeEnd("www.domain.com", "domain") = "www.domain.com"
 StringUtils.removeEnd("abc", "")    = "abc"
 
 
	                
	                
 
		                        Since: 2.1 
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the source String to search, may be null
				
	
                    


String

 
                    remove
                    the String to search for and remove, may be null
				
 
    




 

	
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 removeStart
                
 public static     

String

removeStart
(




String



str,




String



remove
)

                
	                
Removes a substring only if it is at the begining of a source string,
 otherwise returns the source string.

 A null source string will return null.
 An empty ("") source string will return the empty string.
 A null search string will return the source string.

  StringUtils.removeStart(null, *)      = null
 StringUtils.removeStart("", *)        = ""
 StringUtils.removeStart(*, null)      = *
 StringUtils.removeStart("www.domain.com", "www.")   = "domain.com"
 StringUtils.removeStart("domain.com", "www.")       = "domain.com"
 StringUtils.removeStart("www.domain.com", "domain") = "www.domain.com"
 StringUtils.removeStart("abc", "")    = "abc"
 
 
	                
	                
 
		                        Since: 2.1 
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the source String to search, may be null
				
	
                    


String

 
                    remove
                    the String to search for and remove, may be null
				
 
    




 

	
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 repeat
                
 public static     

String

repeat
(




String



str,



int



repeat
)

                
	                
Repeat a String repeat times to form a
 new String.

  StringUtils.repeat(null, 2) = null
 StringUtils.repeat("", 0)   = ""
 StringUtils.repeat("", 2)   = ""
 StringUtils.repeat("a", 3)  = "aaa"
 StringUtils.repeat("ab", 2) = "abab"
 StringUtils.repeat("a", -2) = ""
 
 
	                
	                
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to repeat, may be null
				
	
                    

int

 
                    repeat
                    number of times to repeat str, negative treated as zero
				
 
    




 

	
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 replace
                
 public static     

String

replace
(




String



text,




String



repl,




String



with
)

                
	                
Replaces all occurrences of a String within another String.

 A null reference passed to this method is a no-op.

  StringUtils.replace(null, *, *)        = null
 StringUtils.replace("", *, *)          = ""
 StringUtils.replace("any", null, *)    = "any"
 StringUtils.replace("any", *, null)    = "any"
 StringUtils.replace("any", "", *)      = "any"
 StringUtils.replace("aba", "a", null)  = "aba"
 StringUtils.replace("aba", "a", "")    = "b"
 StringUtils.replace("aba", "a", "z")   = "zbz"
 
 
	                
	                
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    text
                    text to search and replace in, may be null
				
	
                    


String

 
                    repl
                    the String to search for, may be null
				
	
                    


String

 
                    with
                    the String to replace with, may be null
				
 
    




  
							See also
replace(String, String, String, int)
 


	
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 replace
                
 public static     

String

replace
(




String



text,




String



repl,




String



with,



int



max
)

                
	                
Replaces a String with another String inside a larger String,
 for the first max values of the search String.

 A null reference passed to this method is a no-op.

  StringUtils.replace(null, *, *, *)         = null
 StringUtils.replace("", *, *, *)           = ""
 StringUtils.replace("any", null, *, *)     = "any"
 StringUtils.replace("any", *, null, *)     = "any"
 StringUtils.replace("any", "", *, *)       = "any"
 StringUtils.replace("any", *, *, 0)        = "any"
 StringUtils.replace("abaa", "a", null, -1) = "abaa"
 StringUtils.replace("abaa", "a", "", -1)   = "b"
 StringUtils.replace("abaa", "a", "z", 0)   = "abaa"
 StringUtils.replace("abaa", "a", "z", 1)   = "zbaa"
 StringUtils.replace("abaa", "a", "z", 2)   = "zbza"
 StringUtils.replace("abaa", "a", "z", -1)  = "zbzz"
 
 
	                
	                
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    text
                    text to search and replace in, may be null
				
	
                    


String

 
                    repl
                    the String to search for, may be null
				
	
                    


String

 
                    with
                    the String to replace with, may be null
				
	
                    

int

 
                    max
                    maximum number of values to replace, or -1 if no maximum
				
 
    




 

	
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 replaceChars
                
 public static     

String

replaceChars
(




String



str,



char



searchChar,



char



replaceChar
)

                
	                
Replaces all occurrences of a character in a String with another.
 This is a null-safe version of  replace(char, char) .

 A null string input returns null.
 An empty ("") string input returns an empty string.

  StringUtils.replaceChars(null, *, *)        = null
 StringUtils.replaceChars("", *, *)          = ""
 StringUtils.replaceChars("abcba", 'b', 'y') = "aycya"
 StringUtils.replaceChars("abcba", 'z', 'y') = "abcba"
 
 
	                
	                
 
		                        Since: 2.0 
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    String to replace characters in, may be null
				
	
                    

char

 
                    searchChar
                    the character to search for, may be null
				
	
                    

char

 
                    replaceChar
                    the character to replace, may be null
				
 
    




 

	
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 replaceChars
                
 public static     

String

replaceChars
(




String



str,




String



searchChars,




String



replaceChars
)

                
	                
Replaces multiple characters in a String in one go.
 This method can also be used to delete characters.

 For example:

 replaceChars("hello", "ho", "jy") = jelly.

 A null string input returns null.
 An empty ("") string input returns an empty string.
 A null or empty set of search characters returns the input string.

 The length of the search characters should normally equal the length
 of the replace characters.
 If the search characters is longer, then the extra search characters
 are deleted.
 If the search characters is shorter, then the extra replace characters
 are ignored.

  StringUtils.replaceChars(null, *, *)           = null
 StringUtils.replaceChars("", *, *)             = ""
 StringUtils.replaceChars("abc", null, *)       = "abc"
 StringUtils.replaceChars("abc", "", *)         = "abc"
 StringUtils.replaceChars("abc", "b", null)     = "ac"
 StringUtils.replaceChars("abc", "b", "")       = "ac"
 StringUtils.replaceChars("abcba", "bc", "yz")  = "ayzya"
 StringUtils.replaceChars("abcba", "bc", "y")   = "ayya"
 StringUtils.replaceChars("abcba", "bc", "yzx") = "ayzya"
 
 
	                
	                
 
		                        Since: 2.0 
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    String to replace characters in, may be null
				
	
                    


String

 
                    searchChars
                    a set of characters to search for, may be null
				
	
                    


String

 
                    replaceChars
                    a set of characters to replace, may be null
				
 
    




 

	
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 replaceOnce
                
 public static     

String

replaceOnce
(




String



text,




String



repl,




String



with
)

                
	                
Replaces a String with another String inside a larger String, once.

 A null reference passed to this method is a no-op.

  StringUtils.replaceOnce(null, *, *)        = null
 StringUtils.replaceOnce("", *, *)          = ""
 StringUtils.replaceOnce("any", null, *)    = "any"
 StringUtils.replaceOnce("any", *, null)    = "any"
 StringUtils.replaceOnce("any", "", *)      = "any"
 StringUtils.replaceOnce("aba", "a", null)  = "aba"
 StringUtils.replaceOnce("aba", "a", "")    = "ba"
 StringUtils.replaceOnce("aba", "a", "z")   = "zba"
 
 
	                
	                
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    text
                    text to search and replace in, may be null
				
	
                    


String

 
                    repl
                    the String to search for, may be null
				
	
                    


String

 
                    with
                    the String to replace with, may be null
				
 
    




  
							See also
replace(String, String, String, int)
 


	
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 reverse
                
 public static     

String

reverse
(




String



str
)

                
	                
Reverses a String as per  reverse() .

 A null String returns null.

  StringUtils.reverse(null)  = null
 StringUtils.reverse("")    = ""
 StringUtils.reverse("bat") = "tab"
 
 
	                
	                
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to reverse, may be null
				
 
    




 

	
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 reverseDelimited
                
 public static     

String

reverseDelimited
(




String



str,



char



separatorChar
)

                
	                
Reverses a String that is delimited by a specific character.

 The Strings between the delimiters are not reversed.
 Thus java.lang.String becomes String.lang.java (if the delimiter
 is '.').

  StringUtils.reverseDelimited(null, *)      = null
 StringUtils.reverseDelimited("", *)        = ""
 StringUtils.reverseDelimited("a.b.c", 'x') = "a.b.c"
 StringUtils.reverseDelimited("a.b.c", ".") = "c.b.a"
 
 
	                
	                
 
		                        Since: 2.0 
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to reverse, may be null
				
	
                    

char

 
                    separatorChar
                    the separator character to use
				
 
    




 

	
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 reverseDelimitedString
                
 public static     

String

reverseDelimitedString
(




String



str,




String



separatorChars
)

                
	                
Reverses a String that is delimited by a specific character.

 The Strings between the delimiters are not reversed.
 Thus java.lang.String becomes String.lang.java (if the delimiter
 is ".").

  StringUtils.reverseDelimitedString(null, *)       = null
 StringUtils.reverseDelimitedString("",*)          = ""
 StringUtils.reverseDelimitedString("a.b.c", null) = "a.b.c"
 StringUtils.reverseDelimitedString("a.b.c", ".")  = "c.b.a"
 
 
	                
	                
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to reverse, may be null
				
	
                    


String

 
                    separatorChars
                    the separator characters to use, null treated as whitespace
				
 
    




 

	
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 right
                
 public static     

String

right
(




String



str,



int



len
)

                
	                
Gets the rightmost len characters of a String.

 If len characters are not available, or the String
 is null, the String will be returned without an
 an exception. An exception is thrown if len is negative.

  StringUtils.right(null, *)    = null
 StringUtils.right(*, -ve)     = ""
 StringUtils.right("", *)      = ""
 StringUtils.right("abc", 0)   = ""
 StringUtils.right("abc", 2)   = "bc"
 StringUtils.right("abc", 4)   = "abc"
 
 
	                
	                
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to get the rightmost characters from, may be null
				
	
                    

int

 
                    len
                    the length of the required String, must be zero or positive
				
 
    




 

	
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 rightPad
                
 public static     

String

rightPad
(




String



str,



int



size
)

                
	                
Right pad a String with spaces (' ').

 The String is padded to the size of size.

  StringUtils.rightPad(null, *)   = null
 StringUtils.rightPad("", 3)     = "   "
 StringUtils.rightPad("bat", 3)  = "bat"
 StringUtils.rightPad("bat", 5)  = "bat  "
 StringUtils.rightPad("bat", 1)  = "bat"
 StringUtils.rightPad("bat", -1) = "bat"
 
 
	                
	                
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to pad out, may be null
				
	
                    

int

 
                    size
                    the size to pad to
				
 
    




 

	
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 rightPad
                
 public static     

String

rightPad
(




String



str,



int



size,



char



padChar
)

                
	                
Right pad a String with a specified character.

 The String is padded to the size of size.

  StringUtils.rightPad(null, *, *)     = null
 StringUtils.rightPad("", 3, 'z')     = "zzz"
 StringUtils.rightPad("bat", 3, 'z')  = "bat"
 StringUtils.rightPad("bat", 5, 'z')  = "batzz"
 StringUtils.rightPad("bat", 1, 'z')  = "bat"
 StringUtils.rightPad("bat", -1, 'z') = "bat"
 
 
	                
	                
 
		                        Since: 2.0 
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to pad out, may be null
				
	
                    

int

 
                    size
                    the size to pad to
				
	
                    

char

 
                    padChar
                    the character to pad with
				
 
    




 

	
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 rightPad
                
 public static     

String

rightPad
(




String



str,



int



size,




String



padStr
)

                
	                
Right pad a String with a specified String.

 The String is padded to the size of size.

  StringUtils.rightPad(null, *, *)      = null
 StringUtils.rightPad("", 3, "z")      = "zzz"
 StringUtils.rightPad("bat", 3, "yz")  = "bat"
 StringUtils.rightPad("bat", 5, "yz")  = "batyz"
 StringUtils.rightPad("bat", 8, "yz")  = "batyzyzy"
 StringUtils.rightPad("bat", 1, "yz")  = "bat"
 StringUtils.rightPad("bat", -1, "yz") = "bat"
 StringUtils.rightPad("bat", 5, null)  = "bat  "
 StringUtils.rightPad("bat", 5, "")    = "bat  "
 
 
	                
	                
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to pad out, may be null
				
	
                    

int

 
                    size
                    the size to pad to
				
	
                    


String

 
                    padStr
                    the String to pad with, null or empty treated as single space
				
 
    




 

	
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 split
                
 public static     

String[]

split
(




String



str
)

                
	                
Splits the provided text into an array, using whitespace as the
 separator.
 Whitespace is defined by  isWhitespace(char) .

 The separator is not included in the returned String array.
 Adjacent separators are treated as one separator.
 For more control over the split use the StrTokenizer class.

 A null input String returns null.

  StringUtils.split(null)       = null
 StringUtils.split("")         = []
 StringUtils.split("abc def")  = ["abc", "def"]
 StringUtils.split("abc  def") = ["abc", "def"]
 StringUtils.split(" abc ")    = ["abc"]
 
 
	                
	                
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to parse, may be null
				
 
    




 

	
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 split
                
 public static     

String[]

split
(




String



str,



char



separatorChar
)

                
	                
Splits the provided text into an array, separator specified.
 This is an alternative to using StringTokenizer.

 The separator is not included in the returned String array.
 Adjacent separators are treated as one separator.
 For more control over the split use the StrTokenizer class.

 A null input String returns null.

  StringUtils.split(null, *)         = null
 StringUtils.split("", *)           = []
 StringUtils.split("a.b.c", '.')    = ["a", "b", "c"]
 StringUtils.split("a..b.c", '.')   = ["a", "b", "c"]
 StringUtils.split("a:b:c", '.')    = ["a:b:c"]
 StringUtils.split("a\tb\nc", null) = ["a", "b", "c"]
 StringUtils.split("a b c", ' ')    = ["a", "b", "c"]
 
 
	                
	                
 
		                        Since: 2.0 
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to parse, may be null
				
	
                    

char

 
                    separatorChar
                    the character used as the delimiter,
  null splits on whitespace
				
 
    




 

	
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 split
                
 public static     

String[]

split
(




String



str,




String



separatorChars
)

                
	                
Splits the provided text into an array, separators specified.
 This is an alternative to using StringTokenizer.

 The separator is not included in the returned String array.
 Adjacent separators are treated as one separator.
 For more control over the split use the StrTokenizer class.

 A null input String returns null.
 A null separatorChars splits on whitespace.

  StringUtils.split(null, *)         = null
 StringUtils.split("", *)           = []
 StringUtils.split("abc def", null) = ["abc", "def"]
 StringUtils.split("abc def", " ")  = ["abc", "def"]
 StringUtils.split("abc  def", " ") = ["abc", "def"]
 StringUtils.split("ab:cd:ef", ":") = ["ab", "cd", "ef"]
 
 
	                
	                
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to parse, may be null
				
	
                    


String

 
                    separatorChars
                    the characters used as the delimiters,
  null splits on whitespace
				
 
    




 

	
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 split
                
 public static     

String[]

split
(




String



str,




String



separatorChars,



int



max
)

                
	                
Splits the provided text into an array with a maximum length,
 separators specified.

 The separator is not included in the returned String array.
 Adjacent separators are treated as one separator.

 A null input String returns null.
 A null separatorChars splits on whitespace.

 If more than max delimited substrings are found, the last
 returned string includes all characters after the first max - 1
 returned strings (including separator characters).

  StringUtils.split(null, *, *)            = null
 StringUtils.split("", *, *)              = []
 StringUtils.split("ab de fg", null, 0)   = ["ab", "cd", "ef"]
 StringUtils.split("ab   de fg", null, 0) = ["ab", "cd", "ef"]
 StringUtils.split("ab:cd:ef", ":", 0)    = ["ab", "cd", "ef"]
 StringUtils.split("ab:cd:ef", ":", 2)    = ["ab", "cd:ef"]
 
 
	                
	                
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to parse, may be null
				
	
                    


String

 
                    separatorChars
                    the characters used as the delimiters,
  null splits on whitespace
				
	
                    

int

 
                    max
                    the maximum number of elements to include in the
  array. A zero or negative value implies no limit
				
 
    




 

	
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 splitByWholeSeparator
                
 public static     

String[]

splitByWholeSeparator
(




String



str,




String



separator
)

                
	                
Splits the provided text into an array, separator string specified.

 The separator(s) will not be included in the returned String array.
 Adjacent separators are treated as one separator.

 A null input String returns null.
 A null separator splits on whitespace.

  StringUtils.split(null, *)            = null
 StringUtils.split("", *)              = []
 StringUtils.split("ab de fg", null)   = ["ab", "de", "fg"]
 StringUtils.split("ab   de fg", null) = ["ab", "de", "fg"]
 StringUtils.split("ab:cd:ef", ":")    = ["ab", "cd", "ef"]
 StringUtils.split("abstemiouslyaeiouyabstemiously", "aeiouy")  = ["bst", "m", "sl", "bst", "m", "sl"]
 StringUtils.split("abstemiouslyaeiouyabstemiously", "aeiouy")  = ["abstemiously", "abstemiously"]
 
 
	                
	                
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to parse, may be null
				
	
                    


String

 
                    separator
                    String containing the String to be used as a delimiter,
  null splits on whitespace
				
 
    




 

	
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 splitByWholeSeparator
                
 public static     

String[]

splitByWholeSeparator
(




String



str,




String



separator,



int



max
)

                
	                
Splits the provided text into an array, separator string specified.
 Returns a maximum of max substrings.

 The separator(s) will not be included in the returned String array.
 Adjacent separators are treated as one separator.

 A null input String returns null.
 A null separator splits on whitespace.

  StringUtils.splitByWholeSeparator(null, *, *)               = null
 StringUtils.splitByWholeSeparator("", *, *)                 = []
 StringUtils.splitByWholeSeparator("ab de fg", null, 0)      = ["ab", "de", "fg"]
 StringUtils.splitByWholeSeparator("ab   de fg", null, 0)    = ["ab", "de", "fg"]
 StringUtils.splitByWholeSeparator("ab:cd:ef", ":", 2)       = ["ab", "cd"]
 StringUtils.splitByWholeSeparator("abstemiouslyaeiouyabstemiously", "aeiouy", 2) = ["bst", "m"]
 StringUtils.splitByWholeSeparator("abstemiouslyaeiouyabstemiously", "aeiouy", 2)  = ["abstemiously", "abstemiously"]
 
 
	                
	                
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to parse, may be null
				
	
                    


String

 
                    separator
                    String containing the String to be used as a delimiter,
  null splits on whitespace
				
	
                    

int

 
                    max
                    the maximum number of elements to include in the returned
  array. A zero or negative value implies no limit.
				
 
    




 

	
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 splitPreserveAllTokens
                
 public static     

String[]

splitPreserveAllTokens
(




String



str
)

                
	                
Splits the provided text into an array, using whitespace as the
 separator, preserving all tokens, including empty tokens created by 
 adjacent separators. This is an alternative to using StringTokenizer.
 Whitespace is defined by  isWhitespace(char) .

 The separator is not included in the returned String array.
 Adjacent separators are treated as separators for empty tokens.
 For more control over the split use the StrTokenizer class.

 A null input String returns null.

  StringUtils.splitPreserveAllTokens(null)       = null
 StringUtils.splitPreserveAllTokens("")         = []
 StringUtils.splitPreserveAllTokens("abc def")  = ["abc", "def"]
 StringUtils.splitPreserveAllTokens("abc  def") = ["abc", "", "def"]
 StringUtils.splitPreserveAllTokens(" abc ")    = ["", "abc", ""]
 
 
	                
	                
 
		                        Since: 2.1 
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to parse, may be null
				
 
    




 

	
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 splitPreserveAllTokens
                
 public static     

String[]

splitPreserveAllTokens
(




String



str,



char



separatorChar
)

                
	                
Splits the provided text into an array, separator specified,
 preserving all tokens, including empty tokens created by adjacent
 separators. This is an alternative to using StringTokenizer.

 The separator is not included in the returned String array.
 Adjacent separators are treated as separators for empty tokens.
 For more control over the split use the StrTokenizer class.

 A null input String returns null.

  StringUtils.splitPreserveAllTokens(null, *)         = null
 StringUtils.splitPreserveAllTokens("", *)           = []
 StringUtils.splitPreserveAllTokens("a.b.c", '.')    = ["a", "b", "c"]
 StringUtils.splitPreserveAllTokens("a..b.c", '.')   = ["a", "b", "c"]
 StringUtils.splitPreserveAllTokens("a:b:c", '.')    = ["a:b:c"]
 StringUtils.splitPreserveAllTokens("a\tb\nc", null) = ["a", "b", "c"]
 StringUtils.splitPreserveAllTokens("a b c", ' ')    = ["a", "b", "c"]
 StringUtils.splitPreserveAllTokens("a b c ", ' ')   = ["a", "b", "c", ""]
 StringUtils.splitPreserveAllTokens("a b c ", ' ')   = ["a", "b", "c", "", ""]
 StringUtils.splitPreserveAllTokens(" a b c", ' ')   = ["", a", "b", "c"]
 StringUtils.splitPreserveAllTokens("  a b c", ' ')  = ["", "", a", "b", "c"]
 StringUtils.splitPreserveAllTokens(" a b c ", ' ')  = ["", a", "b", "c", ""]
 
 
	                
	                
 
		                        Since: 2.1 
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to parse, may be null
				
	
                    

char

 
                    separatorChar
                    the character used as the delimiter,
  null splits on whitespace
				
 
    




 

	
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 splitPreserveAllTokens
                
 public static     

String[]

splitPreserveAllTokens
(




String



str,




String



separatorChars
)

                
	                
Splits the provided text into an array, separators specified, 
 preserving all tokens, including empty tokens created by adjacent
 separators. This is an alternative to using StringTokenizer.

 The separator is not included in the returned String array.
 Adjacent separators are treated as separators for empty tokens.
 For more control over the split use the StrTokenizer class.

 A null input String returns null.
 A null separatorChars splits on whitespace.

  StringUtils.splitPreserveAllTokens(null, *)           = null
 StringUtils.splitPreserveAllTokens("", *)             = []
 StringUtils.splitPreserveAllTokens("abc def", null)   = ["abc", "def"]
 StringUtils.splitPreserveAllTokens("abc def", " ")    = ["abc", "def"]
 StringUtils.splitPreserveAllTokens("abc  def", " ")   = ["abc", "", def"]
 StringUtils.splitPreserveAllTokens("ab:cd:ef", ":")   = ["ab", "cd", "ef"]
 StringUtils.splitPreserveAllTokens("ab:cd:ef:", ":")  = ["ab", "cd", "ef", ""]
 StringUtils.splitPreserveAllTokens("ab:cd:ef::", ":") = ["ab", "cd", "ef", "", ""]
 StringUtils.splitPreserveAllTokens("ab::cd:ef", ":")  = ["ab", "", cd", "ef"]
 StringUtils.splitPreserveAllTokens(":cd:ef", ":")     = ["", cd", "ef"]
 StringUtils.splitPreserveAllTokens("::cd:ef", ":")    = ["", "", cd", "ef"]
 StringUtils.splitPreserveAllTokens(":cd:ef:", ":")    = ["", cd", "ef", ""]
 
 
	                
	                
 
		                        Since: 2.1 
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to parse, may be null
				
	
                    


String

 
                    separatorChars
                    the characters used as the delimiters,
  null splits on whitespace
				
 
    




 

	
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 splitPreserveAllTokens
                
 public static     

String[]

splitPreserveAllTokens
(




String



str,




String



separatorChars,



int



max
)

                
	                
Splits the provided text into an array with a maximum length,
 separators specified, preserving all tokens, including empty tokens 
 created by adjacent separators.

 The separator is not included in the returned String array.
 Adjacent separators are treated as separators for empty tokens.
 Adjacent separators are treated as one separator.

 A null input String returns null.
 A null separatorChars splits on whitespace.

 If more than max delimited substrings are found, the last
 returned string includes all characters after the first max - 1
 returned strings (including separator characters).

  StringUtils.splitPreserveAllTokens(null, *, *)            = null
 StringUtils.splitPreserveAllTokens("", *, *)              = []
 StringUtils.splitPreserveAllTokens("ab de fg", null, 0)   = ["ab", "cd", "ef"]
 StringUtils.splitPreserveAllTokens("ab   de fg", null, 0) = ["ab", "cd", "ef"]
 StringUtils.splitPreserveAllTokens("ab:cd:ef", ":", 0)    = ["ab", "cd", "ef"]
 StringUtils.splitPreserveAllTokens("ab:cd:ef", ":", 2)    = ["ab", "cd:ef"]
 StringUtils.splitPreserveAllTokens("ab   de fg", null, 2) = ["ab", "  de fg"]
 StringUtils.splitPreserveAllTokens("ab   de fg", null, 3) = ["ab", "", " de fg"]
 StringUtils.splitPreserveAllTokens("ab   de fg", null, 4) = ["ab", "", "", "de fg"]
 
 
	                
	                
 
		                        Since: 2.1 
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to parse, may be null
				
	
                    


String

 
                    separatorChars
                    the characters used as the delimiters,
  null splits on whitespace
				
	
                    

int

 
                    max
                    the maximum number of elements to include in the
  array. A zero or negative value implies no limit
				
 
    




 

	
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 strip
                
 public static     

String

strip
(




String



str
)

                
	                
Strips whitespace from the start and end of a String.

 This is similar to  trim(String)  but removes whitespace.
 Whitespace is defined by  isWhitespace(char) .

 A null input String returns null.

  StringUtils.strip(null)     = null
 StringUtils.strip("")       = ""
 StringUtils.strip("   ")    = ""
 StringUtils.strip("abc")    = "abc"
 StringUtils.strip("  abc")  = "abc"
 StringUtils.strip("abc  ")  = "abc"
 StringUtils.strip(" abc ")  = "abc"
 StringUtils.strip(" ab c ") = "ab c"
 
 
	                
	                
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to remove whitespace from, may be null
				
 
    




 

	
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 strip
                
 public static     

String

strip
(




String



str,




String



stripChars
)

                
	                
Strips any of a set of characters from the start and end of a String.
 This is similar to  trim()  but allows the characters
 to be stripped to be controlled.

 A null input String returns null.
 An empty string ("") input returns the empty string.

 If the stripChars String is null, whitespace is
 stripped as defined by  isWhitespace(char) .
 Alternatively use  strip(String) .

  StringUtils.strip(null, *)          = null
 StringUtils.strip("", *)            = ""
 StringUtils.strip("abc", null)      = "abc"
 StringUtils.strip("  abc", null)    = "abc"
 StringUtils.strip("abc  ", null)    = "abc"
 StringUtils.strip(" abc ", null)    = "abc"
 StringUtils.strip("  abcyx", "xyz") = "  abc"
 
 
	                
	                
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to remove characters from, may be null
				
	
                    


String

 
                    stripChars
                    the characters to remove, null treated as whitespace
				
 
    




 

	
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 stripAll
                
 public static     

String[]

stripAll
(




String


[]
strs
)

                
	                
Strips whitespace from the start and end of every String in an array.
 Whitespace is defined by  isWhitespace(char) .

 A new array is returned each time, except for length zero.
 A null array will return null.
 An empty array will return itself.
 A null array entry will be ignored.

  StringUtils.stripAll(null)             = null
 StringUtils.stripAll([])               = []
 StringUtils.stripAll(["abc", "  abc"]) = ["abc", "abc"]
 StringUtils.stripAll(["abc  ", null])  = ["abc", null]
 
 
	                
	                
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String
[]
 
                    strs
                    the array to remove whitespace from, may be null
				
 
    




 

	
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 stripAll
                
 public static     

String[]

stripAll
(




String


[]
strs,




String



stripChars
)

                
	                
Strips any of a set of characters from the start and end of every
 String in an array.
 Whitespace is defined by  isWhitespace(char) .

 A new array is returned each time, except for length zero.
 A null array will return null.
 An empty array will return itself.
 A null array entry will be ignored.
 A null stripChars will strip whitespace as defined by
  isWhitespace(char) .

  StringUtils.stripAll(null, *)                = null
 StringUtils.stripAll([], *)                  = []
 StringUtils.stripAll(["abc", "  abc"], null) = ["abc", "abc"]
 StringUtils.stripAll(["abc  ", null], null)  = ["abc", null]
 StringUtils.stripAll(["abc  ", null], "yz")  = ["abc  ", null]
 StringUtils.stripAll(["yabcz", null], "yz")  = ["abc", null]
 
 
	                
	                
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String
[]
 
                    strs
                    the array to remove characters from, may be null
				
	
                    


String

 
                    stripChars
                    the characters to remove, null treated as whitespace
				
 
    




 

	
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 stripEnd
                
 public static     

String

stripEnd
(




String



str,




String



stripChars
)

                
	                
Strips any of a set of characters from the end of a String.

 A null input String returns null.
 An empty string ("") input returns the empty string.

 If the stripChars String is null, whitespace is
 stripped as defined by  isWhitespace(char) .

  StringUtils.stripEnd(null, *)          = null
 StringUtils.stripEnd("", *)            = ""
 StringUtils.stripEnd("abc", "")        = "abc"
 StringUtils.stripEnd("abc", null)      = "abc"
 StringUtils.stripEnd("  abc", null)    = "  abc"
 StringUtils.stripEnd("abc  ", null)    = "abc"
 StringUtils.stripEnd(" abc ", null)    = " abc"
 StringUtils.stripEnd("  abcyx", "xyz") = "  abc"
 
 
	                
	                
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to remove characters from, may be null
				
	
                    


String

 
                    stripChars
                    the characters to remove, null treated as whitespace
				
 
    




 

	
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 stripStart
                
 public static     

String

stripStart
(




String



str,




String



stripChars
)

                
	                
Strips any of a set of characters from the start of a String.

 A null input String returns null.
 An empty string ("") input returns the empty string.

 If the stripChars String is null, whitespace is
 stripped as defined by  isWhitespace(char) .

  StringUtils.stripStart(null, *)          = null
 StringUtils.stripStart("", *)            = ""
 StringUtils.stripStart("abc", "")        = "abc"
 StringUtils.stripStart("abc", null)      = "abc"
 StringUtils.stripStart("  abc", null)    = "abc"
 StringUtils.stripStart("abc  ", null)    = "abc  "
 StringUtils.stripStart(" abc ", null)    = "abc "
 StringUtils.stripStart("yxabc  ", "xyz") = "abc  "
 
 
	                
	                
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to remove characters from, may be null
				
	
                    


String

 
                    stripChars
                    the characters to remove, null treated as whitespace
				
 
    




 

	
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 stripToEmpty
                
 public static     

String

stripToEmpty
(




String



str
)

                
	                
Strips whitespace from the start and end of a String  returning
 an empty String if null input.

 This is similar to  trimToEmpty(String)  but removes whitespace.
 Whitespace is defined by  isWhitespace(char) .

  StringUtils.strip(null)     = ""
 StringUtils.strip("")       = ""
 StringUtils.strip("   ")    = ""
 StringUtils.strip("abc")    = "abc"
 StringUtils.strip("  abc")  = "abc"
 StringUtils.strip("abc  ")  = "abc"
 StringUtils.strip(" abc ")  = "abc"
 StringUtils.strip(" ab c ") = "ab c"
 
 
	                
	                
 
		                        Since: 2.0 
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to be stripped, may be null
				
 
    




 

	
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 stripToNull
                
 public static     

String

stripToNull
(




String



str
)

                
	                
Strips whitespace from the start and end of a String  returning
 null if the String is empty ("") after the strip.

 This is similar to  trimToNull(String)  but removes whitespace.
 Whitespace is defined by  isWhitespace(char) .

  StringUtils.strip(null)     = null
 StringUtils.strip("")       = null
 StringUtils.strip("   ")    = null
 StringUtils.strip("abc")    = "abc"
 StringUtils.strip("  abc")  = "abc"
 StringUtils.strip("abc  ")  = "abc"
 StringUtils.strip(" abc ")  = "abc"
 StringUtils.strip(" ab c ") = "ab c"
 
 
	                
	                
 
		                        Since: 2.0 
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to be stripped, may be null
				
 
    




 

	
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 substring
                
 public static     

String

substring
(




String



str,



int



start
)

                
	                
Gets a substring from the specified String avoiding exceptions.

 A negative start position can be used to start n
 characters from the end of the String.

 A null String will return null.
 An empty ("") String will return "".

  StringUtils.substring(null, *)   = null
 StringUtils.substring("", *)     = ""
 StringUtils.substring("abc", 0)  = "abc"
 StringUtils.substring("abc", 2)  = "c"
 StringUtils.substring("abc", 4)  = ""
 StringUtils.substring("abc", -2) = "bc"
 StringUtils.substring("abc", -4) = "abc"
 
 
	                
	                
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to get the substring from, may be null
				
	
                    

int

 
                    start
                    the position to start from, negative means
  count back from the end of the String by this many characters
				
 
    




 

	
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 substring
                
 public static     

String

substring
(




String



str,



int



start,



int



end
)

                
	                
Gets a substring from the specified String avoiding exceptions.

 A negative start position can be used to start/end n
 characters from the end of the String.

 The returned substring starts with the character in the start
 position and ends before the end position. All position counting is
 zero-based -- i.e., to start at the beginning of the string use
 start = 0. Negative start and end positions can be used to
 specify offsets relative to the end of the String.

 If start is not strictly to the left of end, ""
 is returned.

  StringUtils.substring(null, *, *)    = null
 StringUtils.substring("", * ,  *)    = "";
 StringUtils.substring("abc", 0, 2)   = "ab"
 StringUtils.substring("abc", 2, 0)   = ""
 StringUtils.substring("abc", 2, 4)   = "c"
 StringUtils.substring("abc", 4, 6)   = ""
 StringUtils.substring("abc", 2, 2)   = ""
 StringUtils.substring("abc", -2, -1) = "b"
 StringUtils.substring("abc", -4, 2)  = "ab"
 
 
	                
	                
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to get the substring from, may be null
				
	
                    

int

 
                    start
                    the position to start from, negative means
  count back from the end of the String by this many characters
				
	
                    

int

 
                    end
                    the position to end at (exclusive), negative means
  count back from the end of the String by this many characters
				
 
    




 

	
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 substringAfter
                
 public static     

String

substringAfter
(




String



str,




String



separator
)

                
	                
Gets the substring after the first occurrence of a separator.
 The separator is not returned.

 A null string input will return null.
 An empty ("") string input will return the empty string.
 A null separator will return the empty string if the
 input string is not null.

  StringUtils.substringAfter(null, *)      = null
 StringUtils.substringAfter("", *)        = ""
 StringUtils.substringAfter(*, null)      = ""
 StringUtils.substringAfter("abc", "a")   = "bc"
 StringUtils.substringAfter("abcba", "b") = "cba"
 StringUtils.substringAfter("abc", "c")   = ""
 StringUtils.substringAfter("abc", "d")   = ""
 StringUtils.substringAfter("abc", "")    = "abc"
 
 
	                
	                
 
		                        Since: 2.0 
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to get a substring from, may be null
				
	
                    


String

 
                    separator
                    the String to search for, may be null
				
 
    




 

	
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 substringAfterLast
                
 public static     

String

substringAfterLast
(




String



str,




String



separator
)

                
	                
Gets the substring after the last occurrence of a separator.
 The separator is not returned.

 A null string input will return null.
 An empty ("") string input will return the empty string.
 An empty or null separator will return the empty string if
 the input string is not null.

  StringUtils.substringAfterLast(null, *)      = null
 StringUtils.substringAfterLast("", *)        = ""
 StringUtils.substringAfterLast(*, "")        = ""
 StringUtils.substringAfterLast(*, null)      = ""
 StringUtils.substringAfterLast("abc", "a")   = "bc"
 StringUtils.substringAfterLast("abcba", "b") = "a"
 StringUtils.substringAfterLast("abc", "c")   = ""
 StringUtils.substringAfterLast("a", "a")     = ""
 StringUtils.substringAfterLast("a", "z")     = ""
 
 
	                
	                
 
		                        Since: 2.0 
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to get a substring from, may be null
				
	
                    


String

 
                    separator
                    the String to search for, may be null
				
 
    




 

	
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 substringBefore
                
 public static     

String

substringBefore
(




String



str,




String



separator
)

                
	                
Gets the substring before the first occurrence of a separator.
 The separator is not returned.

 A null string input will return null.
 An empty ("") string input will return the empty string.
 A null separator will return the input string.

  StringUtils.substringBefore(null, *)      = null
 StringUtils.substringBefore("", *)        = ""
 StringUtils.substringBefore("abc", "a")   = ""
 StringUtils.substringBefore("abcba", "b") = "a"
 StringUtils.substringBefore("abc", "c")   = "ab"
 StringUtils.substringBefore("abc", "d")   = "abc"
 StringUtils.substringBefore("abc", "")    = ""
 StringUtils.substringBefore("abc", null)  = "abc"
 
 
	                
	                
 
		                        Since: 2.0 
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to get a substring from, may be null
				
	
                    


String

 
                    separator
                    the String to search for, may be null
				
 
    




 

	
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 substringBeforeLast
                
 public static     

String

substringBeforeLast
(




String



str,




String



separator
)

                
	                
Gets the substring before the last occurrence of a separator.
 The separator is not returned.

 A null string input will return null.
 An empty ("") string input will return the empty string.
 An empty or null separator will return the input string.

  StringUtils.substringBeforeLast(null, *)      = null
 StringUtils.substringBeforeLast("", *)        = ""
 StringUtils.substringBeforeLast("abcba", "b") = "abc"
 StringUtils.substringBeforeLast("abc", "c")   = "ab"
 StringUtils.substringBeforeLast("a", "a")     = ""
 StringUtils.substringBeforeLast("a", "z")     = "a"
 StringUtils.substringBeforeLast("a", null)    = "a"
 StringUtils.substringBeforeLast("a", "")      = "a"
 
 
	                
	                
 
		                        Since: 2.0 
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to get a substring from, may be null
				
	
                    


String

 
                    separator
                    the String to search for, may be null
				
 
    




 

	
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 substringBetween
                
 public static     

String

substringBetween
(




String



str,




String



tag
)

                
	                
Gets the String that is nested in between two instances of the
 same String.

 A null input String returns null.
 A null tag returns null.

  StringUtils.substringBetween(null, *)            = null
 StringUtils.substringBetween("", "")             = ""
 StringUtils.substringBetween("", "tag")          = null
 StringUtils.substringBetween("tagabctag", null)  = null
 StringUtils.substringBetween("tagabctag", "")    = ""
 StringUtils.substringBetween("tagabctag", "tag") = "abc"
 
 
	                
	                
 
		                        Since: 2.0 
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String containing the substring, may be null
				
	
                    


String

 
                    tag
                    the String before and after the substring, may be null
				
 
    




 

	
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 substringBetween
                
 public static     

String

substringBetween
(




String



str,




String



open,




String



close
)

                
	                
Gets the String that is nested in between two Strings.
 Only the first match is returned.

 A null input String returns null.
 A null open/close returns null (no match).
 An empty ("") open/close returns an empty string.

  StringUtils.substringBetween(null, *, *)          = null
 StringUtils.substringBetween("", "", "")          = ""
 StringUtils.substringBetween("", "", "tag")       = null
 StringUtils.substringBetween("", "tag", "tag")    = null
 StringUtils.substringBetween("yabcz", null, null) = null
 StringUtils.substringBetween("yabcz", "", "")     = ""
 StringUtils.substringBetween("yabcz", "y", "z")   = "abc"
 StringUtils.substringBetween("yabczyabcz", "y", "z")   = "abc"
 
 
	                
	                
 
		                        Since: 2.0 
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String containing the substring, may be null
				
	
                    


String

 
                    open
                    the String before the substring, may be null
				
	
                    


String

 
                    close
                    the String after the substring, may be null
				
 
    




 

	
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 swapCase
                
 public static     

String

swapCase
(




String



str
)

                
	                
Swaps the case of a String changing upper and title case to
 lower case, and lower case to upper case.

 
  Upper case character converts to Lower case
  Title case character converts to Lower case
  Lower case character converts to Upper case
 

 For a word based algorithm, see  swapCase(String) .
 A null input String returns null.

  StringUtils.swapCase(null)                 = null
 StringUtils.swapCase("")                   = ""
 StringUtils.swapCase("The dog has a BONE") = "tHE DOG HAS A bone"
 

 NOTE: This method changed in Lang version 2.0.
 It no longer performs a word based algorithm.
 If you only use ASCII, you will notice no change.
 That functionality is available in WordUtils.
 
	                
	                
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to swap case, may be null
				
 
    




 

	
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 trim
                
 public static     

String

trim
(




String



str
)

                
	                
Removes control characters (char <= 32) from both
 ends of this String, handling null by returning
 null.

 The String is trimmed using  trim() .
 Trim removes start and end characters <= 32.
 To strip whitespace use  strip(String) .

 To trim your choice of characters, use the
  strip(String, String)  methods.

  StringUtils.trim(null)          = null
 StringUtils.trim("")            = ""
 StringUtils.trim("     ")       = ""
 StringUtils.trim("abc")         = "abc"
 StringUtils.trim("    abc    ") = "abc"
 
 
	                
	                
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to be trimmed, may be null
				
 
    




 

	
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 trimToEmpty
                
 public static     

String

trimToEmpty
(




String



str
)

                
	                
Removes control characters (char <= 32) from both
 ends of this String returning an empty String ("") if the String
 is empty ("") after the trim or if it is null.

 
The String is trimmed using  trim() .
 Trim removes start and end characters <= 32.
 To strip whitespace use  stripToEmpty(String) .

  StringUtils.trimToEmpty(null)          = ""
 StringUtils.trimToEmpty("")            = ""
 StringUtils.trimToEmpty("     ")       = ""
 StringUtils.trimToEmpty("abc")         = "abc"
 StringUtils.trimToEmpty("    abc    ") = "abc"
 
 
	                
	                
 
		                        Since: 2.0 
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to be trimmed, may be null
				
 
    




 

	
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 trimToNull
                
 public static     

String

trimToNull
(




String



str
)

                
	                
Removes control characters (char <= 32) from both
 ends of this String returning null if the String is
 empty ("") after the trim or if it is null.

 
The String is trimmed using  trim() .
 Trim removes start and end characters <= 32.
 To strip whitespace use  stripToNull(String) .

  StringUtils.trimToNull(null)          = null
 StringUtils.trimToNull("")            = null
 StringUtils.trimToNull("     ")       = null
 StringUtils.trimToNull("abc")         = "abc"
 StringUtils.trimToNull("    abc    ") = "abc"
 
 
	                
	                
 
		                        Since: 2.0 
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to be trimmed, may be null
				
 
    




 

	
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 uncapitalise
                
 public static     

String

uncapitalise
(




String



str
)

                
	                
Uncapitalizes a String changing the first letter to title case as
 per  toLowerCase(char) . No other letters are changed.
 
	                
	                
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to uncapitalize, may be null
				
 
    




 

	
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 uncapitalize
                
 public static     

String

uncapitalize
(




String



str
)

                
	                
Uncapitalizes a String changing the first letter to title case as
 per  toLowerCase(char) . No other letters are changed.

 For a word based algorithm, see  uncapitalize(String) .
 A null input String returns null.

  StringUtils.uncapitalize(null)  = null
 StringUtils.uncapitalize("")    = ""
 StringUtils.uncapitalize("Cat") = "cat"
 StringUtils.uncapitalize("CAT") = "cAT"
 
 
	                
	                
 
		                        Since: 2.0 
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to uncapitalize, may be null
				
 
    




  
							See also
uncapitalize(String)
capitalize(String)
 


	
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 upperCase
                
 public static     

String

upperCase
(




String



str
)

                
	                
Converts a String to upper case as per  toUpperCase() .

 A null input String returns null.

  StringUtils.upperCase(null)  = null
 StringUtils.upperCase("")    = ""
 StringUtils.upperCase("aBc") = "ABC"
 
 
	                
	                
 




	Parameters
    	
            
                Type Name Description
            
	
                    


String

 
                    str
                    the String to upper case, may be null
				
 
    




 

	
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Type	Name	Description
String	str	the String to pad out, may be null
int	size	the size to pad to

Type	Name	Description
String	str	the String to get the characters from, may be null
int	pos	the position to start from, negative treated as zero
int	len	the length of the required String, must be zero or positive

Type	Name	Description
String	str	the String to do overlaying in, may be null
String	overlay	the String to overlay, may be null
int	start	the position to start overlaying at
int	end	the position to stop overlaying before

Type	Name	Description
String	text	the String to do overlaying in, may be null
String	overlay	the String to overlay, may be null
int	start	the position to start overlaying at, must be valid
int	end	the position to stop overlaying before, must be valid

Type	Name	Description
String	str	the source String to search, may be null
String	remove	the String to search for and remove, may be null

Type	Name	Description
String	str	the String to repeat, may be null
int	repeat	number of times to repeat str, negative treated as zero

Type	Name	Description
String	text	text to search and replace in, may be null
String	repl	the String to search for, may be null
String	with	the String to replace with, may be null

Type	Name	Description
String	str	String to replace characters in, may be null
char	searchChar	the character to search for, may be null
char	replaceChar	the character to replace, may be null

Type	Name	Description
String	str	the String to reverse, may be null
char	separatorChar	the separator character to use

Type	Name	Description
String	str	the String to get the rightmost characters from, may be null
int	len	the length of the required String, must be zero or positive

Type	Name	Description
String	str	the String to parse, may be null
char	separatorChar	the character used as the delimiter, `null` splits on whitespace

Type	Name	Description
String	str	the String to parse, may be `null`
char	separatorChar	the character used as the delimiter, `null` splits on whitespace

Type	Name	Description
String	str	the String to remove characters from, may be null
String	stripChars	the characters to remove, null treated as whitespace

Type	Name	Description
String []	strs	the array to remove characters from, may be null
String	stripChars	the characters to remove, null treated as whitespace

Type	Name	Description
String	str	the String to get the substring from, may be null
int	start	the position to start from, negative means count back from the end of the String by this many characters

Type	Name	Description
String	str	the String to get a substring from, may be null
String	separator	the String to search for, may be null

Type	Name	Description
String	str	the String containing the substring, may be null
String	tag	the String before and after the substring, may be null