<?xml version="1.0" encoding="UTF-8"?>

<Context>

    <!-- Specify a JDBC datasource -->

    <Resource name="jdbc/库名" auth="Container" type="javax.sql.DataSource"

              maxActive="100" maxIdle="30" maxWait="10000"

              username="javauser" password="javadude" driverClassName="com.mysql.jdbc.Driver"

              url="jdbc:mysql://localhost:3306/库名"/>

</Context>

<web-app xmlns="http://java.sun.com/xml/ns/j2ee"

    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

    xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee

http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"

    version="2.4">

  <description>MySQL Test App</description>

  <resource-ref>

      <description>DB Connection</description>

      <res-ref-name>jdbc/数据库名</res-ref-name>

      <res-type>javax.sql.DataSource</res-type>

      <res-auth>Container</res-auth>

  </resource-ref>

</web-app>

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.SQLException;

import javax.naming.Context;

import javax.naming.InitialContext;

import javax.naming.NamingException;

import javax.sql.DataSource;

public class ConnectionManager

{

    private static DataSource dataSource;

    private static Connection conn;

    public static Connection getConnection() throws InstantiationException, IllegalAccessException

    {

        try

        {

           /*System.out.println("Connecting to database");

            String url = "jdbc:mysql://localhost:3306/";

            String dbName ="test"; //  name of Database.

            String uname = "root";

            String pwd = "";

            Class.forName("com.mysql.jdbc.Driver");

            */

             Context initContext  = new InitialContext();

             Context envContext  = (Context)initContext.lookup("java:/comp/env");

             dataSource = (DataSource)envContext.lookup("jdbc/库名");

            try

            {

               //conn = DriverManager.getConnection(url+dbName,uname,pwd);

               conn = dataSource.getConnection();

            }

            catch (SQLException ex)

            {

                ex.printStackTrace();

            }

        }

        catch (NamingException e) {

			// TODO Auto-generated catch block

			e.printStackTrace();

		}

        return conn;

    }

}