jsp的session完成登陆功能

浏览数：30 / 时间：2015年06月09日

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 1 <%@ page language="java" import="java.util.*" contentType="text/html; charset=utf-8"%>
 2 <%
 3 String path = request.getContextPath();
 4 String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
 5 %>
 6 
 7 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
 8 <html>
 9   <head>
10     <base href="<%=basePath%>">
11     
12     <title>用户登录</title>
13     
14     <meta http-equiv="pragma" content="no-cache">
15     <meta http-equiv="cache-control" content="no-cache">
16     <meta http-equiv="expires" content="0">    
17     <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
18     <meta http-equiv="description" content="This is my page">
19     <!--
20     <link rel="stylesheet" type="text/css" href="styles.css">
21     -->
22 
23   </head>
24   
25   <body>
26     <h1>用户登录</h1>
27     <form action="check" method="post">
28         <table border="1" width="250px">
29             <tr><td>用户名:</td><td><input type="text" name="userId" /></td></tr>
30             <tr><td>密码:</td><td><input type="password" name="passwd" /></td></tr>
31             <tr><td></td><td><input type="submit" value="提交" /></td></tr>
32         </table>
33     </form>
34   </body>
35 </html>

welcom.jsp

 1 <%@ page language="java" import="java.util.*" contentType="text/html; charset=utf-8"%>
 2 <%
 3 String path = request.getContextPath();
 4 String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
 5 %>
 6 
 7 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
 8 <html>
 9   <head>
10     <base href="<%=basePath%>">
11     
12     <title>My JSP ‘welcome.jsp‘ starting page</title>
13     
14     <meta http-equiv="pragma" content="no-cache">
15     <meta http-equiv="cache-control" content="no-cache">
16     <meta http-equiv="expires" content="0">    
17     <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
18     <meta http-equiv="description" content="This is my page">    
19   </head>
20      <%
21         String user=(String) session.getAttribute("user");
22         if(user==null){
23         %>
24         <jsp:forward page="login.jsp" />
25         <%} %>
26   <body>
27  热烈欢迎您:<%=user %>
28   </body>
29 </html>

web.xml

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <web-app version="2.5" 
 3     xmlns="http://java.sun.com/xml/ns/javaee" 
 4     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
 5     xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
 6     http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
 7   <display-name></display-name>    
 8   <welcome-file-list>
 9     <welcome-file>index.jsp</welcome-file>
10   </welcome-file-list>
11   <servlet>
12       <servlet-name>CheckUser</servlet-name>
13       <servlet-class>servlet.CheckUser</servlet-class>
14   </servlet>
15   <servlet-mapping>
16       <servlet-name>CheckUser</servlet-name>
17       <url-pattern>/check</url-pattern>
18   </servlet-mapping>
19   
20 </web-app>

CheckUser.java

 1 package servlet;
 2 
 3 import java.io.IOException;
 4 
 5 import javax.servlet.RequestDispatcher;
 6 import javax.servlet.ServletException;
 7 import javax.servlet.http.HttpServlet;
 8 import javax.servlet.http.HttpServletRequest;
 9 import javax.servlet.http.HttpServletResponse;
10 import javax.servlet.http.HttpSession;
11 
12 public class CheckUser extends HttpServlet {
13     @Override
14     protected void doPost(HttpServletRequest request,
15             HttpServletResponse response) throws ServletException, IOException {
16             request.setCharacterEncoding("UTF-8");
17             String userId=request.getParameter("userId");
18             String passwd=request.getParameter("passwd");
19             
20             if(userId!=null&&passwd!=null&&userId.equals("gys")&&passwd.equals("gys")){
21                 HttpSession session=request.getSession();
22                 session.setAttribute("user", userId);
23                 RequestDispatcher dispatcher=request.getRequestDispatcher("/welcome.jsp");
24                 dispatcher.forward(request, response);
25             }
26             else{
27                 RequestDispatcher dispatcher=request.getRequestDispatcher("/login.jsp");
28                 dispatcher.forward(request, response);
29             }
30     }
31 }