java网络编程－Ajax servlet实例
文章作者 100test 发表时间 2007:03:14 16:27:29
来源 100Test.Com百考试题网
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
AJAX.html
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.0deleteRow(1).
}
}
function MyShow(){//2秒自动刷新一次,2秒取得一次数据.
timer = window.setInterval("getResult()",2000).
}
onload="MyShow()">
width="47%" height="23" border="0" cellpadding="1" cellspacing="0" id="tb">
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