配置和使用服务器Tomcat连接池

<?xml version='1.0' encoding='utf-8'?>

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  this work for additional information regarding copyright ownership.

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<!-- The contents of this file will be loaded for each web application -->

<Context reloadable="true">

    <!-- Default set of monitored resources -->

    <WatchedResource>WEB-INF/web.xml</WatchedResource>

    <!-- Uncomment this to disable session persistence across Tomcat restarts -->

    <!--

    <Manager pathname="" />

    -->

    <!-- Uncomment this to enable Comet connection tacking (provides events

         on session expiration as well as webapp lifecycle) -->

    <!--

    <Valve className="org.apache.catalina.valves.CometConnectionManagerValve" />

    -->

    <Resource name="jdbc/DBWater" auth="Container"

    	Type="javax.sql.DataSource"

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

    	username="root" password="root"

    	driverClassName="com.mysql.jdbc.Driver"

    	url="jdbc:mysql://localhost:3306/testmysql"

    />

</Context>

//引入包

package com.cjg.test;

import java.sql.Connection;

import java.sql.ResultSet;

import javax.naming.InitialContext;

import javax.sql.DataSource;

import java.sql.Statement;

public class DBWater {

	//定义三个对象name 、number、sex

	String name;

	int number;

	boolean sex;

	public String getName() {

		return name;

	}

	public int getNumber() {

		return number;

	}

	public boolean isSex() {

		return sex;

	}

    //初始化一些对象

	public void init() {

        try {

            //创建InitialContext对象

        	InitialContext initc  = new InitialContext();

            if (initc == null)

                throw new Exception("No Context");

            /*

             * 在下面的字符串"java:comp/env/jdbc/DBWater"中，*"java:comp/env/"是不变的，

             * 而"jdbc/DBWater"配置文件数据源名称

             */

            DataSource ds = (DataSource)initc.lookup("java:comp/env/jdbc/DBWater");

            if (ds != null) {

                Connection conn = ds.getConnection();                    //得到连接对象

                if (conn != null) {

                	Statement stmt=conn.createStatement();      //创建陈述对象

                    //得到运行结果

                    ResultSet rst=stmt.executeQuery("select   *   from   student");

                    //遍历运行结果

                    while (rst.next()) {

                        number=rst.getInt(1);

                        name=rst.getString(2);

                    }

                    conn.close();                                         //关闭连接对象

                }

            }

        } catch (Exception e) {

            e.printStackTrace();

        }

    }

}

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

<web-app version="2.5"

	xmlns="http://java.sun.com/xml/ns/javaee"

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

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

	http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">

  <welcome-file-list>

    <welcome-file>index.jsp</welcome-file>

  </welcome-file-list>

   <resource-ref>

   <!-- 描述信息 -->

    <description>Connection Pool</description>

    <!-- 数据源名字 -->

    <res-ref-name>jdbc/DBWater</res-ref-name>

    <!-- 数据源的类型 -->

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

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

    <res-sharing-scope>Shareable</res-sharing-scope>

 </resource-ref>

 </web-app>