T - the result type
@FunctionalInterface public interface ConnectionCallback<T>
This is particularly useful for delegating to existing data access code
that expects a Connection to work on and throws SQLException. For newly
written code, it is strongly recommended to use JdbcTemplate's more specific
operations, for example a
@Nullable T doInConnection(Connection con) throws SQLException, DataAccessException
JdbcTemplate.execute with an active JDBC
Connection. Does not need to care about activating or closing the
Connection, or handling transactions.
If called without a thread-bound JDBC transaction (initiated by DataSourceTransactionManager), the code will simply get executed on the JDBC connection with its transactional semantics. If JdbcTemplate is configured to use a JTA-aware DataSource, the JDBC Connection and thus the callback code will be transactional if a JTA transaction is active.
Allows for returning a result object created within the callback, i.e.
a domain object or a collection of domain objects. Note that there's special
support for single step actions: see
etc. A thrown RuntimeException is treated as application exception:
it gets propagated to the caller of the template.
con - active JDBC Connection
null if none
SQLException - if thrown by a JDBC method, to be auto-converted
to a DataAccessException by an SQLExceptionTranslator
DataAccessException - in case of custom exceptions