Web开发8：使用JavaScript与Servlet实现客户端与服务器端验证
下面写一个注册页面
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?register.jsp，主要用JS进行验证
<%@ 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6if(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" onsubmit="return validate()"> --> <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
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
<%@ 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
<%@ 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>?