login.jsp:
<%@ page language="java" import="java.util.*" contentType="text/html; charset=utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>" rel="external nofollow" rel="external nofollow" > <title>用户登录</title> <meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css" rel="external nofollow" >
--> </head> <body>
<h1>用户登录</h1>
<form action="check" method="post">
<table border="1" width="250px">
<tr><td>用户名:</td><td><input type="text" name="userId" /></td></tr>
<tr><td>密码:</td><td><input type="password" name="passwd" /></td></tr>
<tr><td></td><td><input type="submit" value="提交" /></td></tr>
</table>
</form>
</body>
</html>
welcom.jsp
<%@ page language="java" import="java.util.*" contentType="text/html; charset=utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>" rel="external nofollow" rel="external nofollow" > <title>My JSP 'welcome.jsp' starting page</title> <meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
</head>
<%
String user=(String) session.getAttribute("user");
if(user==null){
%>
<jsp:forward page="login.jsp" />
<%} %>
<body>
热烈欢迎您:<%=user %>
</body>
</html>
web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5"
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<display-name></display-name>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
<servlet>
<servlet-name>CheckUser</servlet-name>
<servlet-class>servlet.CheckUser</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>CheckUser</servlet-name>
<url-pattern>/check</url-pattern>
</servlet-mapping> </web-app>
CheckUser.java
package servlet; import java.io.IOException; import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession; public class CheckUser extends HttpServlet {
@Override
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");
String userId=request.getParameter("userId");
String passwd=request.getParameter("passwd"); if(userId!=null&&passwd!=null&&userId.equals("gys")&&passwd.equals("gys")){
HttpSession session=request.getSession();
session.setAttribute("user", userId);
RequestDispatcher dispatcher=request.getRequestDispatcher("/welcome.jsp");
dispatcher.forward(request, response);
}
else{
RequestDispatcher dispatcher=request.getRequestDispatcher("/login.jsp");
dispatcher.forward(request, response);
}
}
}
