[Springframework-developer] potential JdbcTemplate bug

[Trevor C. <pr...@se...>]

I'm currently rewriting some of the tests for the jdbc package, and I have
encountered a potential problem.  Specifically, in the JdbcTemplate
"doWithResultSetFromPreparedQuery" method, exception handling does not
appear to always work.  Recently changes were made which placed various
"close" calls in a catch (SQLException) block.  However, if a Spring
exception is thrown (I noticed this by running a SqlFunction which returned
more than 1 row, thus throwing an "InvalidDataAccessApiUsageException") the
"SQLException" catch is NOT called, and the method exits without closing
resultset/preparedstatements, etc.  Note that while I noticed this in the
single method, this behaviour permeates the JdbcTemplate.

The current ("paraphrased") code is:

<code>
try {
	... various code ...
	SQLWarning warning = ps.getWarnings();
	rs.close();
	ps.close();
	throwExceptionOnWarningIfNotIgnoringWarnings(warning);
} catch (SQLException ex) {
	if (rs != null) {
		try {
			rs.close();
		} catch (SQLException ignore) {}
	}
	if (ps != null) {
		try {
			ps.close();
		} catch (SQLException ignore) {}
	}
	throw getExceptionTranslator().translate("JdbcTemplate.query(psc) with
PreparedStatementCreator [" + psc + "]", null, ex);
} finally {
	DataSourceUtils.closeConnectionIfNecessary(con, this.dataSource);
}
</code>

I propose changing it to:

<code>
try {
	... various code ...
	SQLWarning warning = ps.getWarnings();
	throwExceptionOnWarningIfNotIgnoringWarnings(warning);
} catch (SQLException ex) {
	throw getExceptionTranslator().translate("JdbcTemplate.query(psc) with
PreparedStatementCreator [" + psc + "]", null, ex);
} finally {
	if (rs != null) {
		try {
			rs.close();
		} catch (SQLException ignore) {}
	}
	if (ps != null) {
		try {
			ps.close();
		} catch (SQLException ignore) {}
	}
	DataSourceUtils.closeConnectionIfNecessary(con, this.dataSource);
}
</code>

I believe this will ensure resources are closed regardless of
success/failure, and still allow Spring exceptions and "translated"
SQLExceptions to propogate as designed.  If anyone sees any holes in this
(specifically Rod/Thomas who I believe have done the most work on the jdbc
packages) please let me know.  Otherwise (and barring exceptions) I will
make the changes and commit them with the updated tests tomorrow.

Trevor D. Cook