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 }