第一个Ajax注册验证

发布时间：2020-12-16 01:56:37 所属栏目：百科来源：网络整理

导读：一、jsp页面 %@ page language="java" import="java.util.*" pageEncoding="UTF-8"% % String path = request.getContextPath(); String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; % html head

一、jsp页面

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<html>
<head>
<base href="<%=basePath%>">
<title>注册界面</title>
<style type="text/css">
.msg{ font-size:12px;}
</style>
</head>

<script language="javascript">
var flag=false;
var xmlhttp;
function createXHR(){
var xmlhttp;
if(window.XMLHttpRequest){
xmlhttp=new XMLHttpRequest();
}else{
xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
return xmlhttp;
}

function checkNameExists(){
var name=document.getElementById("name").value;
xmlhttp=createXHR();
xmlhttp.onreadystatechange=callback;
xmlhttp.open("get","RegistCheckNameServlet?name="+name);
xmlhttp.send(null);
}

function callback(){
if(xmlhttp.readyState==4){
var txt=xmlhttp.responseText;
if(txt=="false"){
document.getElementById("nameInfo").innerHTML="<font color='green'>恭喜你,该用户名可以使用!</font>";
flag=true;
}else{
document.getElementById("nameInfo").innerHTML="<font color='red'>该用户名已经被占用!</font>";
/*document.getElementById("name").value="";
document.getElementById("name").focus();*/
}
}
}
function checkForm(){
return flag;
}
</script>

<body>
<center>
<h1>注册界面</h1>
<form action="RegistServlet" method="post" onsubmit="return checkForm()">
请输入用户名 :<input type="text" name="name" id="name" onblur="checkNameExists()"/><span id="nameInfo" class="msg"></span><br/>
 请输入密码   :<input type="text" name="pwd" /><br/>
请再次确认密码:<input type="text" name="pwd" /><br/>
<input type="submit" value="提交" />
</form>
</center>
</body>
</html>

二、RegistCheckNameServlet

public class RegistCheckNameServlet extends HttpServlet{ protected void service(HttpServletRequest request,HttpServletResponse response) throws ServletException,IOException { String name = new String(request.getParameter("name").getBytes("iso-8859-1"),"utf-8"); PrintWriter out = response.getWriter(); String flag = "false"; UserDao ud = new UserDaoImpl(); if (ud.findUserByName(name)) { flag = "true"; } out.print(flag); out.close(); } }

（编辑：李大同）

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