Tomcat下使用c3p0配置jndi数据源

下载c3p0包：

下载地址：https://sourceforge.net/projects/c3p0/files/?source=navbar

解压后得到包：c3p0-0.9.2.jar，mchange-commons-java-0.2.11.jar

下载mysql包：

下载地址：http://download.csdn.net/download/u010802461/9579306

解压后得到包：mysql-connector-java-5.1.39-bin.jar(笔者这里没有是因为我将包放到Tomcat服务器的lib文件夹下)

将包都拷贝到项目lib下，注意外部mysql必须开启

在META-INF中新建context.xml

并且在context.xml中添加代码

<?xml version="1.0" encoding="UTF-8"?>
<Context>
    <!-- 使用C3P0配置针对MySQL数据库的JNDI数据源 -->
   <Resource
        name="jdbc/mysql"
        auth="Container"
        factory="org.apache.naming.factory.BeanFactory"
        type="com.mchange.v2.c3p0.ComboPooledDataSource"
        driverClass="com.mysql.jdbc.Driver"
        idleConnectionTestPeriod="60"
        maxPoolSize="50"
        minPoolSize="2"
        acquireIncrement="2"
        user="root"
        password="root"
        jdbcUrl="jdbc:mysql://localhost:3306/mysql?useUnicode=true&amp;characterEncoding=utf-8"/>
</Context>

context.xml的代码

在Web.xml配置文件中写代码

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">
  <display-name>Test1</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>
  <resource-ref>
    <res-ref-name>jdbc/mysql</res-ref-name>
    <res-type>javax.sql.DataSource</res-type>
    <res-auth>Container</res-auth>
  </resource-ref>
</web-app>

Web.xml代码

测试代码是否正常运行

package com.c3p0.jndi;

import java.io.IOException;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.sql.DataSource;

@WebServlet("/Testc3p0")
public class Testc3p0 extends HttpServlet {
    private static final long serialVersionUID = 1L;
    public Testc3p0() {
        super();
    }
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        ResultSet rs = null;
        try {
            //此类是执行命名操作的初始上下文。用于解析该 URL
            InitialContext ctx = new InitialContext();
            //lookup检索配置。
            DataSource ds = (DataSource)ctx.lookup("java:comp/env/jdbc/mysql");
            //获取连接
            Connection con = ds.getConnection();
            /*Statement stmt = con.createStatement();
            rs = stmt.executeQuery("select count(*) as ant from user");
            while(rs.next()){
                if(rs!=null){
                    System.out.println(rs.getInt("ant"));
                }
            }*/
            System.out.println(ds.getConnection());
        } catch (NamingException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        doGet(request, response);
    }

}