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" 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>
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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); } }
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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>
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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>
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