login.jsp: 1 <%@ page language="java" import="java.util.*" contentType="text/html; charset=utf-8"%> 2 <% 3 String path = request.getContextPath(); 4 S
login.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>用戶登錄</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>用戶登錄</h1> 27 <form action="check" method="post"> 28 <table border="1" width="250px"> 29 <tr><td>用戶名:</td><td><input type="text" name="userId" /></td></tr> 30 <tr><td>密碼:</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 熱烈歡迎您:<%=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 }
