Re: More Finally
In article <e56dncE-fNgX-ybbRVnyjwA@bt.com>,
RedGrittyBrick <RedGrittyBrick@SpamWeary.foo> wrote:
Given this code ...
Connection connection = DriverManager.getConnection(driver, id, pw);
Statement statement = connection.createStatement();
ResultSet resultSet = statement.executeQuery(sql);
while (resultSet.next()) {
String name = resultSet.getString(1);
String phone = resultSet.getString(2);
System.out.println(name + ": " + phone);
}
resultSet.close();
statement.close();
connection.close();
Sun's examples[1] put those statements into a single try block with no
finally clause and don't really attempt to release local or server
resources.
In the dirt-simple, example case, resources are released when the object is
garbage collected. In almost any real code, that's not good enough.
So far as I can see, to have the resource releasing code in a finally
block would require at three nested try/catch/finally structures - one
for each resource we want to close if it is open.
The pattern I normally see is:
Connecton connection = null;
try {
connection = Something.getConnection();
... do work ...
} finally {
if (connection != null) try { connection.close(); }
catch (SQLException ignore) { }
}
AFAIK, closing the connection closes all resources opened through that
connection, including resources used by Statement and ResultSet objects.
If you wanted to use the Connection for multiple Statements, and be sure to
close each of them between uses, you'd need to nest try/finally.
--
Mark Rafn dagon@dagon.net <http://www.dagon.net/>