How can i get connection from connection pool tomcat 8

Question

I am learning how to work with Servlet api and trying to develop my first web application. And I have a problem with JDBC connection. I understand how I can connect to my DB, but I want to get connection from connection pool. I dont understand how I can work with it. Can you give me advice or link to example application to see how it works?

Answer 1

GenericObjectPool class can be used to create pool of arbitrary objects. You can create pool as below.

public DataSource setUpPool() throws Exception {

Class.forName(JDBC_DRIVER);
// Creates an Instance of GenericObjectPool That Holds Our Pool of Connections Object!
        gPool = new GenericObjectPool();
        gPool.setMaxActive(5);
// Creates a ConnectionFactory Object Which Will Be Use by the Pool to Create the Connection Object!

ConnectionFactory cf = new DriverManagerConnectionFactory(JDBC_DB_URL, JDBC_USER, JDBC_PASS);

// Creates a PoolableConnectionFactory That Will Wraps the Connection Object Created by the ConnectionFactory to Add Object Pooling Functionality!


PoolableConnectionFactory pcf = new PoolableConnectionFactory(cf, gPool, null, null, false, true);

return new PoolingDataSource(gPool);
}

Get connection from pool using above method:

ConnectionPool jdbcObj = new ConnectionPool();
Connection connObj = null;
DataSource dataSource = jdbcObj.setUpPool();
connObj = dataSource.getConnection();