This class can be implemented by application developers, although this is not
necessary, as BeanNameUrlHandlerMapping
are included in the framework. The former is the default if no
HandlerMapping bean is registered in the application context.
HandlerMapping implementations can support mapped interceptors but do not
have to. A handler will always be wrapped in a HandlerExecutionChain
instance, optionally accompanied by some HandlerInterceptor instances.
The DispatcherServlet will first call each HandlerInterceptor's
preHandle method in the given order, finally invoking the handler
itself if all preHandle methods have returned true.
The ability to parameterize this mapping is a powerful and unusual
capability of this MVC framework. For example, it is possible to write
a custom mapping based on session state, cookie state or many other
variables. No other MVC framework seems to be equally flexible.
Note: Implementations can implement the Ordered
interface to be able to specify a sorting order and thus a priority for getting
applied by DispatcherServlet. Non-Ordered instances get treated as lowest priority.