使用ajax验证用户名是否重复

来源：互联网发布：java多线程基础编辑：程序博客网时间：2024/06/09 19:27

ajaxTest.jsp

<%@page contentType="text/html"%><%@page pageEncoding="UTF-8"%><!DOCTYPE html><html>    <head>        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">        <title>JSP Page</title>    </head>    <body>    输入用户名：<input type="text" />光标移除检查是否重复    <hr />    <div>显示结果</div>    <script type="text/javascript">    document.getElementsByTagName("input")[0].onblur=function()    {    //alert("aaa");    //取得用户输入的用户名    var username=this.value;    //alert(username)    username=encodeURI(username);    var xhr=createXHR();    //准备以get方式发送请求    xhr.onreadystatechange=function()    {    if(xhr.readyState==4)    {    if(xhr.status==200)    {    var msg=xhr.responseText;    var divlele=document.getElementsByTagName("div")[0];    divlele.innerHTML=msg;    }    }    }    xhr.open("GET","servlet/getServlet?time="+new Date().getTime()+"&username="+username);    xhr.send(null);    }    function createXHR()    {    var xhr=null;    try{    xhr=new ActiveXObject("microsoft.xmlhttp");    }    catch(e)    {    try    {    xhr=new XMLHttpRequest();    }    catch(e)    {    window.alert("浏览器不支持");    }    }    return xhr;    }        </script>     </body></html>

Servlet控制：

package servlet;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 getServlet extends HttpServlet {public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {System.out.println("getservlet:doget");String username = request.getParameter("username");byte[] buf = username.getBytes("UTF-8");username = new String(buf, "UTF-8");String msg = null;if (username.equals("sa")) {msg = "<font color='red'>该用户已经存在</font>";} else {msg = "<font color='green'>可以注册</font>";}response.setContentType("text/html;charset=UTF-8");response.getWriter().write(msg);}}

运行：

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