chklogin.jsp: 
<%@ page language="java" pageEncoding="GBK" import="news.admin.*"%> <!DOCTYPE HTML PUBLIC "-//w3c//dtd html 4.0 transitional//en"> <html> <head> <title>Lomboz JSP</title> </head> <body bgcolor="#FFFFFF"> <%     String username = request.getParameter("username");     String password = request.getParameter("password");     CheckManagers checkManagers = new CheckManagers(); 
        //查询数据库,验证用户名和密码     if (!checkManagers.checkLogin(username, password)) {         %>         username or password may be incorrect. Please go back.<br>         <a href="index.jsp">Return to admin entrance</a>         <%     } else { 
        //用登陆名标示Session。         session.setAttribute("UNIQUE_CHECK_STRING", username);         response.sendRedirect("main.jsp");     } %> </body> </html> 
  
session-guard.jsp: 
<%@ page language="java" pageEncoding="GBK" %> <%     String uniqueCheckString = (String)session.getAttribute("UNIQUE_CHECK_STRING");     if (uniqueCheckString == null) { 
        //销毁当前Session         session.invalidate(); 
        //重定向到WEB应用的首页。转到首页后,服务器会自动创建一个新的Session。这个新的Session不含登陆名标示,无法访问受限页面。         response.sendRedirect(request.getContextPath() + "/index.jsp");     } %>
  
main.jsp: 
//在任何需要保护的JSP页面中加入这一行: 
<%@ include file="/admin/session-guard.jsp" %>  
 
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