PlatformTransactionManager implementation for a single JDBC DataSource. Able to work in any environment with any JDBC driver, as long as the setup uses a JDBC 2.0 Standard Extensions / JDBC 3.0 javax.sql.DataSource as its Connection factory mechanism. Binds a JDBC Connection from the specified DataSource to the thread, potentially allowing for one thread Connection per DataSource.

Application code is required to retrieve the JDBC Connection via DataSourceUtils.getConnection(DataSource) instead of J2EE's standard DataSource.getConnection(). This is recommended anyway, as it throws unchecked org.springframework.dao exceptions instead of checked SQLException. All framework classes like JdbcTemplate use this strategy implicitly. If not used with this transaction manager, the lookup strategy behaves exactly like the common one - it can thus be used in any case.

Alternatively, you can also allow application code to work with the standard J2EE lookup pattern DataSource.getConnection(), for example for legacy code that is not aware of Spring at all. In that case, define a TransactionAwareDataSourceProxy for your target DataSource, and pass that proxy DataSource to your DAOs, which will automatically participate in Spring-managed transactions through it. Note that DataSourceTransactionManager still needs to be wired with the target DataSource, driving transactions for it.

Supports custom isolation levels, and timeouts that get applied as appropriate JDBC statement timeouts. To support the latter, application code must either use JdbcTemplate, call DataSourceUtils.applyTransactionTimeout for each created statement, or go through a TransactionAwareDataSourceProxy which will create timeout-aware Connections and Statements.

Consider defining a LazyConnectionDataSourceProxy for your target DataSource, pointing both this transaction manager and your DAOs to it. This will lead to optimized handling of "empty" transactions, that is, transactions without any statements executed. LazyConnectionDataSourceProxy will not fetch a JDBC Connection from the target DataSource until the first statement execution, lazily applying the specified transaction settings to the target Conection.

On JDBC 3.0, this transaction manager supports nested transactions via JDBC 3.0 Savepoints. The "nestedTransactionAllowed" flag defaults to true, as nested transactions work without restrictions on JDBC drivers that support Savepoints (such as the Oracle JDBC driver).

This implementation can be used as a replacement for JtaTransactionManager in the single resource case, as it does not require a container that supports JTA: typically, in combination with a locally defined JDBC DataSource (e.g. a Jakarta Commons DBCP connection pool). Switching between this local strategy and a JTA environment is just a matter of configuration, if you stick to the required connection lookup pattern. Note that JTA does not support custom isolation levels!