Ajax+Servlet无刷新验证用户名

来源：互联网发布：python时间函数毫秒编辑：程序博客网时间：2024/05/16 17:39

页面端(login.jsp):

<%@ page language="java" import="java.util.*" pageEncoding="gb2312"%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

<html>

<head>

<TITLE>Ajax验证用户名是否存在例子</TITLE>

//设一个变量

var XMLHttpReq=false;

//创建一个XMLHttpRequest对象

function createXMLHttpRequest(){

if(window.XMLHttpRequest){ //Mozilla

XMLHttpReq=new XMLHttpRequest();

}

else if(window.ActiveXObject){

try{

XMLHttpReq=new ActiveXObject("Msxml2.XMLHTTP");

}catch(e){

try{

XMLHttpReq=new ActiveXObject("Microsoft.XMLHTTP");

}catch(e){}

}

//发送请求函数

function send(url){

createXMLHttpRequest();

XMLHttpReq.open("get",url,true);

XMLHttpReq.onreadystatechange=proce; //指定响应的函数

XMLHttpReq.send(null); //发送请求

}

function proce(){

if(XMLHttpReq.readyState==4){ //对象状态

if(XMLHttpReq.status==200){//信息已成功返回，开始处理信息

var root=XMLHttpReq.responseXML;

var res=root.getElementsByTagName("content")[0].firstChild.data;

window.alert(res);

//var xmlReturn = XMLHttpReq.responseText;

//window.alert(xmlReturn);

}else{

window.alert("所请求的页面有异常");

}

//身份验证

function check(){

var name=document.getElementById("name").value;

if(name==""){

alert("请输入姓名!");

return false;

}

else{

//send('login?name='+name);

document.getElementById("load").style.display='';

send('login.do?name='+name);

document.getElementById("load").style.display='none';

}

</script>

</head>

<body>

<table>

<div id=load style="display:none; position:absolute;right:0px;top:0px;background:#FF5B5B;border:1px solid">正在验证用户名,请稍后……</div><p>

</td>

</tr>

</table>

</form>

</body>

</html>

js 代码

AjaxServlet.java

java 代码

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;

public class AjaxServlet extends HttpServlet {

Logger log = Logger.getLogger(this.getClass());

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException,IOException {

response.setContentType("text/xml; charset=GBK");

PrintWriter out = response.getWriter();

out.print(2);

}

//Process the HTTP Post request

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

doGet(request, response);

}

//Process the HTTP Put request

public void doPut(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

}

//Process the HTTP Delete request

public void doDelete(HttpServletRequest request,

HttpServletResponse response) throws ServletException, IOException {

}

//Clean up resources

public void destroy() {

}