Getting and Using Pooled Connections
by, 04-27-2012 at 08:06 PM (728 Views)
A connection pool is a cache of database connection objects. The objects represent physical database connections that can be used by an application to connect to a database. At run time, the application requests a connection from the pool. If the pool contains a connection that can satisfy the request, it returns the connection to the application. If no connections are found, a new connection is created and returned to the application. The application uses the connection to perform some work on the database and then returns the object back to the pool. The connection is then available for the next connection request.
Connection pools promote the reuse of connection objects and reduce the number of times that connection objects are created. Connection pools significantly improve performance for database-intensive applications because creating connection objects is costly both in terms of time and resources.
Now that these DataSource and ConnectionPoolDataSource objects are deployed, a programmer can use the DataSource object to get a pooled connection. The code for getting a pooled connection is just like the code for getting a nonpooled connection, as shown in the following two lines:
Java Code:ctx = new InitialContext(); ds = (DataSource)ctx.lookup("jdbc/testDB");