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使用JavaScript与Servlet实现客户端与服务器端验证

2014-08-26 11:04 495 查看

下面写一个注册页面

register.jsp，主要用JS进行验证

Js代码

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>

<html>

<head>

<script type="text/javascript">

function validate(){

//通过id来取值

var username = document.getElementById("username1");

var password = document.getElementById("password1");

var repassword = document.getElementById("repassword1");

/*通过名称来取值，不过返回的是数组，只取数组中的第一个值

var username = document.getElementsByName("username")[0];

var password = document.getElementsByName("password")[0];

var repassword = document.getElementsByName("repassword")[0];*/

/*或通过getElementsByTagName来取值，同样，它返回的也是一个数组

var inputs = document.getElementsByTagName("input");

for(var i =0;i<inputs.length;i++){

alert(inputs[i].value);

}*/

//用户名不能为空

if(username.value == ""){

alert("username can't be null!");

return false;

}

//密码长度不能少于6

if(password.value.length < 6 || repassword.value.length < 6 ){

alert("password'length can't less than 6");

return false;

}

//密码不相同

if(password.value != repassword.value){

alert("password not same!");

return false;

}

}

</script>

</head>

<body>



<form action="ValidateServlet">

username:<input type="text" name="username" id="username1"><br>

password:<input type="password" name="password" id="password1"><br>

repassword:<input type="password" name="repassword" id="repassword1"><br>

<input type="submit" value="submit">

</form>

</body>

</html>

ValidateServlet.java 在后台进行验证

Java代码

package com.kingdee.servlet;

import java.io.IOException;

import java.util.ArrayList;

import java.util.List;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

public class ValidateServlet extends HttpServlet {

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

String username = request.getParameter("username");

String password = request.getParameter("password");

String repassword = request.getParameter("repassword");

List<String> list = new ArrayList<String>();

if(username == null || "".equals(username)){

list.add("username can't be null");

}

if(password.length() <6 || repassword.length() <6){

list.add("password can't less than 6");

}

if(!password.equals(repassword)){

list.add("password not same");

}

if(list.isEmpty()){

request.setAttribute("username", username);

request.setAttribute("password", password);

request.setAttribute("repassword", repassword);

request.getRequestDispatcher("success.jsp").forward(request, response);

}else{

request.setAttribute("error", list);

request.getRequestDispatcher("error.jsp").forward(request, response);;

}

}

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

super.doPost(request, response);

}

}

success.jsp

Html代码

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>

<html>

<body>

<%

String username = (String)request.getAttribute("username");

String password = (String)request.getAttribute("password");

String repassword = (String)request.getAttribute("repassword");

%>

username:<%=username %><br>

password:<%=password %><br>

repassword:<%=repassword %>

</body>

</html>

error.jsp

Html代码

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>

<html>

<body>

<%

List<String> list = (List<String>)request.getAttribute("error");

%>

<h1>Register Failed!</h1>

<%

for(String str:list){

out.println(str+"<br>");

}

%>

</body>

</html>

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