Good practices: JDBC Connection [duplicate]

Answer 1

best paectise is : use single Connection object for all queries if those queires are part of same method and for each query close the PreparedStatement, after its been used.

Answer 2

Use a Connection pool. So you do not keep creating.

Answer 3

Connection pooling

Use a connection pool. Each transaction in your app will get a connection from this pool, execute all the things needed, rollback or commit and close the connection (it will return the conn to the pool).

You could give you Query object a reference to the pool and open will get the connection and close will close it (returning it in fact).

Prepared Statement

Try to reuse your prepared statement for similar queries. That way the DB will reuse the previous query plan and it will be faster. It has a lot of sense if you are executing a lot of queries of the same form.

How?

• Maintain last PS open
• If you close the connection or whatever, close it
• if you query for the same query string than the previous reuse the PS you saved
• if it's not the same query string... close it and create a new one

Answer 4

You have to close the PreparedStatement after you're done with it and before you create a new one on the same connection. I have had serious problems because I did not close PreparedStatements. It turned out that on the database server there were resources allocated that are only freed after an explicit call of PreparedStatement.close().

As bdares commented, the Connection should be opened and closed as infrequently as possible.