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java网络编程-Ajax+servlet实例

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(){//保留第一行表头,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>

posted on 2008-08-18 11:49 gdufo 阅读(299) 评论(0)  编辑  收藏 所属分类: JAVA 基础

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