JDBC -- Connection Pool

Connection Pool: create many connection objects in advance, and put the connection into the cache(list). The client will get the connection from the cache, return the connectio to the cache after using it. This way could improve the access effeciency of data base.

Simulate the connection pool:

package com.pp.pool;

import java.sql.Connection;
import java.util.ArrayList;
import java.util.List;

import com.pp.util.JdbcUtil;

/*
 * Simulate the completion of connetion pool
 */
public class SimpleConnectionPool {
    private static List<Connection> pool = new ArrayList<Connection>();

    static {
        for (int i = 0; i < 10; i++) {
            Connection conn = JdbcUtil.getConnection();
            pool.add(conn);
        }

    }

    // get the connection object from cache pool
    public synchronized static Connection getConnection() {
        if (pool.size() > 0) {
            Connection conn = pool.remove(0);
            return conn;
        } else {
            throw new RuntimeException("Server is busy!");
        }
    }

    // return the connection
    public static void releas(Connection conn) {
        pool.add(conn);
    }
}