ajax实现注册页面动态验证用户名是否已注册，不必提交即可验证

来源：互联网发布：阿里云 centos 中文编辑：程序博客网时间：2024/06/05 01:01

今天学了一下ajax，感觉很爽啊。ajax真是很强大、

我首先就把我之前一直没解决的问题：如何在前台动态验证用户名是否已注册，而不必提交刷新之后再验证，上代码：

首先，jsp页面：

[java] view plaincopyprint?

<%@ page language="java" import="java.util.*" pageEncoding="GB18030"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'index.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
<input type="text" name="text1" id="text1id" onblur="Ajaxtest1();"><br>
<input type="text" name="text2" id="text2id" /><br>
<%-- <input type="button" value="button" onclick="Ajaxtest1();"><br>--%>
<div id="div1"></div>
</body>
</html>

<%@ page language="java" import="java.util.*" pageEncoding="GB18030"%><%String path = request.getContextPath();String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html>  <head>    <base href="<%=basePath%>">        <title>My JSP 'index.jsp' starting page</title><meta http-equiv="pragma" content="no-cache"><meta http-equiv="cache-control" content="no-cache"><meta http-equiv="expires" content="0">    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"><meta http-equiv="description" content="This is my page"><!--<link rel="stylesheet" type="text/css" href="styles.css">-->  </head>    <body>   <input type="text" name="text1" id="text1id"  onblur="Ajaxtest1();"><br>   <input type="text" name="text2" id="text2id" /><br><%--      <input type="button" value="button" onclick="Ajaxtest1();"><br>--%>   <div id="div1"></div>  </body></html>

这个其实只是两个文本框，输入用、

下面是js代码。验证用的、

[html] view plaincopyprint?

<script type="text/javascript">
var xmlhttprequest=null;
function Ajaxtest1(){
if(window.ActiveXObject){//IE浏览器
xmlhttprequest=new ActiveXObject("Microsoft.XMLHTTP");
}
else if(window.XMLHttpRequest){
xmlhttprequest=new XMLHttpRequest();
}
if(null!=xmlhttprequest){
var text1=document.getElementById("text1id").value;
var text2=document.getElementById("text2id").value;
xmlhttprequest.open("GET", "testajax1?t1="+text1+"&t2="+text2, true);
xmlhttprequest.onreadystatechange=ajaxcallback;
//var tt=document.getElementById("text1").innerHTML;
xmlhttprequest.send(null);
}
}
function ajaxcallback(){
if(xmlhttprequest.readyState==4){
if(xmlhttprequest.status==200){
var text=xmlhttprequest.responseText;
document.getElementById("div1").innerHTML=text;
}
}
}
</script>

<script type="text/javascript">var xmlhttprequest=null;function Ajaxtest1(){if(window.ActiveXObject){//IE浏览器xmlhttprequest=new ActiveXObject("Microsoft.XMLHTTP");}else if(window.XMLHttpRequest){xmlhttprequest=new XMLHttpRequest();}if(null!=xmlhttprequest){var text1=document.getElementById("text1id").value;var text2=document.getElementById("text2id").value;xmlhttprequest.open("GET", "testajax1?t1="+text1+"&t2="+text2, true);xmlhttprequest.onreadystatechange=ajaxcallback;//var tt=document.getElementById("text1").innerHTML;xmlhttprequest.send(null);}}function ajaxcallback(){if(xmlhttprequest.readyState==4){if(xmlhttprequest.status==200){var text=xmlhttprequest.responseText;document.getElementById("div1").innerHTML=text;}}}</script>

这个没什么可说的，唯一注意的一点就是xmlhttprequest.open("GET", "testajax1?t1="+text1+"&t2="+text2, true);

这里面的testajax1是servlet，注意这个地址需和web.xml保持一致。

接下来是testajax1.java

[java] view plaincopyprint?

package com.guang.ajax;
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 com.guang.sqlhelp.sqlhelp;
import java.sql.*;
public class testajax1 extends HttpServlet {
public testajax1() {
super();
}
int i=0;
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("gbk");
response.setContentType("text/html;charset=gbk");
PrintWriter out = response.getWriter();
//System.out.println("doGet"+i);
i++;
String t1=request.getParameter("t1");
//System.out.println(t1);
//out.println("Hello World");
sqlhelp sp=new sqlhelp();
Connection conn=sp.getconn();
Statement sta=sp.getsta2(conn);
String sql="select * from baseinfo where usernum='"+t1+"'";
ResultSet set=sp.getset(sta, sql);
int j=0;
if(set!=null){
try {
set.last();
} catch (SQLException e) {
e.printStackTrace();
}
try {
j=set.getRow();
} catch (SQLException e) {
e.printStackTrace();
}
if(j==1){
out.println("此学号已被注册，请换一个！！");
}
else{
out.println("恭喜您，这个可以注册！");
}
out.close();
}
}
}

0 0