Ajax实现自动刷新页面.doc

所有开发环境：Eclipse4.2 mySQL5.5Tomcat6.0(先把数据库驱动程序加到tomcatlib下)建立的数据库中的表dbname=”person” table=”stuscore”表如下：前提先建好数据库person 建表代码：# Host: localhost (Version: 5.5.20)# Date: 2012-10-16 07:04:12# Generator: MySQL-Front 5.2 (Build 3.32)/*!40101 SET OLD_CHARACTER_SET_CLIENT=CHARACTER_SET_CLIENT */;/*!40101 SET OLD_CHARACTER_SET_RESULTS=CHARACTER_SET_RESULTS */;/*!40101 SET OLD_COLLATION_CONNECTION=COLLATION_CONNECTION */;/*!40101 SET NAMES utf8 */;/*!40101 SET OLD_SQL_MODE=SQL_MODE */;/*!40101 SET SQL_MODE=STRICT_TRANS_TABLES,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION */;/*!40111 SET OLD_SQL_NOTES=SQL_NOTES */;/*!40103 SET SQL_NOTES=ON */;/*!40014 SET OLD_UNIQUE_CHECKS=UNIQUE_CHECKS */;/*!40014 SET UNIQUE_CHECKS=0 */;/*!40014 SET OLD_FOREIGN_KEY_CHECKS=FOREIGN_KEY_CHECKS */;/*!40014 SET FOREIGN_KEY_CHECKS=0 */;# Source for table stuscore#DROP TABLE IF EXISTS stuscore;CREATE TABLE stuscore ( Id int(11) NOT NULL AUTO_INCREMENT, name varchar(255) DEFAULT NULL, grade varchar(255) DEFAULT NULL, score varchar(255) DEFAULT NULL, state int(255) DEFAULT NULL, PRIMARY KEY (Id) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8;# Data for table stuscore#/*!40000 ALTER TABLE stuscore DISABLE KEYS */;INSERT INTO stuscore VALUES (1,杜淳,200401,94.50000,1),(2,马苏,200401,96.70000,1),(3,李晨,200401,95.40000,1),(4,立方,200402,89.70000,1);/*!40000 ALTER TABLE stuscore ENABLE KEYS */;/*!40014 SET FOREIGN_KEY_CHECKS=OLD_FOREIGN_KEY_CHECKS */;/*!40014 SET UNIQUE_CHECKS=OLD_UNIQUE_CHECKS */;/*!40111 SET SQL_NOTES=OLD_SQL_NOTES */;/*!40101 SET SQL_MODE=OLD_SQL_MODE */;/*!40101 SET CHARACTER_SET_CLIENT=OLD_CHARACTER_SET_CLIENT */;/*!40101 SET CHARACTER_SET_RESULTS=OLD_CHARACTER_SET_RESULTS */;/*!40101 SET COLLATION_CONNECTION=OLD_COLLATION_CONNECTION */;本次工程结构如下：其中AutoRefresh.jsp的代码如下：Insert title herevar XMLHttpReq;function createXMLHttpRequest() if(window.XMLHttpRequest) XMLHttpReq=new XMLHttpRequest(); else if(window.ActiveXObject) try XMLHttpReq=new ActiveXObject(Msxml2.XMLHTTP); catch(e)tryXMLHttpReq=new ActiveXObject(Microsoft.XMLHTTP);catch(e) function sendRequest()createXMLHttpRequest();var url=auto;XMLHttpReq.open(GET,url,true);XMLHttpReq.onreadystatechange=processResponse;XMLHttpReq.send(null);function processResponse()if(XMLHttpReq.readyState=4)if(XMLHttpReq.status=200)DisplayHot();setTimeout(sendRequest(),1000);elsewindow.alert(您所请求的页面有异常);function DisplayHot()var num=XMLHttpReq.responseXML.getElementsByTagName(num)0.firstChild.nodeValue;document.getElementById(name).innerHTML=你的新信息数目为;document.getElementById(num).innerHTML=num;消息提示建立servlet程序：AutoRefreshAction.java代码:package com.cong;import java.io.IOException;import java.io.PrintWriter;import java.sql.Connection;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;/import org.apache.tomcat.dbcp.dbcp.ConnectionFactory;/* * Servlet implementation class AutoRefreshAction */public class AutoRefreshAction extends HttpServlet private static final long serialVersionUID = 1L; /* * see HttpServlet#HttpServlet() */ public AutoRefreshAction() super(); / TODO Auto-generated constructor stub /* * see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) */protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException / TODO Auto-generated method stubresponse.setContentType(text/xml;charset=utf-8);response.setHeader(Cache-Control, no-cache);PrintWriter out=response.getWriter();out.println();ConnectionFactory factory=new ConnectionFactory();Connection con=factory.getConnection();Statement st=null; ResultSet rs=null;String strSql=null;strSql=select count(*) from stuscore where state=0 order by id desc;tryst=con.createStatement();rs=st.executeQuery(strSql);if(rs.next()out.println(+rs.getString(1)+);catch(SQLException e)e.printStackTrace();out.println();out.close();/* * see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) */protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException / TODO Auto-generated method stubConnectionFactory.java代码：package com.cong;import java.sql.Connection;import java.sql.DriverManager;public class ConnectionFactory public final static String url=jdbc:mysql:/localhost:3306/person;public final static String user=root;public final static String password=congli;Connection getConnection() try Class.forName(com.mysql.jdbc.Driver); return (Connection) DriverManager.getConnection(url,user,password); c