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Ajax 与 Servlet

2008-03-28 10:56 579 查看

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>

</head>

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>

</tr>

</table>

<form>

<p>输入股票代码:

</p>

<p>你交易的数量:</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>

Welcome to Tomcat

</description>

<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>

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