Ajax异步请求,servlet产生随机数据,Html页面无刷新显示。
运行环境：jdk1.5+tomcat 5.5
一、ajaxServlet.java
- package com;
- import java.io.IOException;
- import java.io.PrintWriter;
- import javax.servlet.ServletException;
- import javax.servlet.http.HttpServlet;
- import javax.servlet.http.HttpServletRequest;
- import javax.servlet.http.HttpServletResponse;
- import java.util.Random;
- public class ajaxServlet extends HttpServlet{
- private static final String CONTENT_TYPE="text/xml; charset=gb2312";
- public void init() throws ServletException{}
- public void doGet(HttpServletRequest request,HttpServletResponse response)
- throws ServletException,IOException{
- response.setContentType(CONTENT_TYPE);
- response.setHeader("Cache-Control","no-cache");
- response.setHeader("Pragma","no-cache");
- response.setDateHeader("Expires",0);
- PrintWriter out=response.getWriter();
- String action=request.getParameter("action");
- if(("send").equals(action)){
- Random random = new Random();
- String AA=Integer.toString(Math.abs(random.nextInt()));
- String BB=Integer.toString(Math.abs(random.nextInt()));
- String CC=Integer.toString(Math.abs(random.nextInt()));
- String DD=Integer.toString(Math.abs(random.nextInt()));
- StringBuffer sb=new StringBuffer();
- sb.append(AA); sb.append("@@@");
- sb.append(BB); sb.append("@@@");
- sb.append(CC); sb.append("@@@");
- sb.append(DD);
- out.write(sb.toString());
- out.close();
- } }}
二、testajax.html
- ﹤html﹥
- ﹤head﹥
- ﹤title﹥AJAX.html﹤/title﹥
- ﹤/head﹥
- ﹤script type="text/javascript"﹥
- function getResult(){
- var url = "/Tajax/AajaxServlet?action=send";
- if (window.XMLHttpRequest) {
- req = new XMLHttpRequest();
- }else if (window.ActiveXObject){
- req = new ActiveXObject("Microsoft.XMLHTTP");
- }
- if(req){
- req.open("GET",url, true);
- req.onreadystatechange = complete;
- req.send(null);
- }
- }
/*分析返回的文本文档*/
- function complete(){
- if (req.readyState == 4) {
- if (req.status == 200) {
- // alert(req.responseText);
- var strResult = unescape(req.responseText);
- var arrResult = strResult.split("@@@");
- RemoveRow(); //删除以前的数据.
- num1 = arrResult[0]; //字段num1的值
- num2 = arrResult[1]; //字段num2的值
- num3 = arrResult[2];
- num4 = arrResult[3];
- row1= tb.insertRow();
- cell1 = row1.insertCell();
- cell1.innerText = num1;
- cell2 = row1.insertCell();
- cell2.innerText = num2;
- row2= tb.insertRow();
- cell3 = row2.insertCell();
- cell3.innerText = num3;
- cell4 = row2.insertCell();
- cell4.innerText = num4;
- } else {
- alert('There was a problem with the request.');
- }
- }
- }
- function RemoveRow(){//保留***行表头,其余数据均删除.
- var iRows = tb.rows.length;
- for(var i=0;i﹤ iRows-1;i++){
- tb.deleteRow(1);
- }
- }
- function MyShow(){//2秒自动刷新一次,2秒取得一次数据.
- timer = window.setInterval("getResult()",2000);
- }
- ﹤/script﹥
- ﹤body onload="MyShow()"﹥
- ﹤table width="47%" height="23" border="0" cellpadding="1" cellspacing="0" id="tb"﹥
- ﹤tr﹥﹤td﹥代码﹤/td﹥
- ﹤td﹥价格﹤/td﹥
- ﹤/tr﹥
- ﹤/table﹥
- ﹤form﹥
- ﹤p﹥输入股票代码:
- ﹤input type="text" size="14" name="phone" id="phone"/﹥
- ﹤/p﹥
- ﹤p﹥你交易的数量:﹤/p﹥
- ﹤p﹥﹤textarea name="order" rows="6" cols="50" id="order"﹥﹤/textarea﹥﹤/p﹥
- ﹤p﹥﹤input type="submit" value="提交" id="submit" /﹥﹤/p﹥
- ﹤/form﹥
- ﹤/body﹥
三、web.xml
- ﹤?xml version="1.0" encoding="ISO-8859-1"?﹥
- ﹤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"﹥
- ﹤display-name﹥Welcome to Tomcat﹤/display-name﹥
- ﹤description﹥
- Welcome to Tomcat
- ﹤/description﹥
- ﹤servlet﹥
- ﹤servlet-name﹥AajaxServlet﹤/servlet-name﹥
- ﹤servlet-class﹥com.ajaxServlet﹤/servlet-class﹥
- ﹤/servlet﹥
- ﹤servlet-mapping﹥
- ﹤servlet-name﹥AajaxServlet﹤/servlet-name﹥
- ﹤url-pattern﹥/AajaxServlet﹤/url-pattern﹥
- ﹤/servlet-mapping﹥
- ﹤/web-app﹥
运行图：
Ajax Servlet实例在网络编程的应用就介绍到这里，是不是有点意思呢？Ajax Servlet实例在网络编程的应用是很广泛的，要在实际中积累和多应用。
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