网站用户登录验证：Servlet+JSP VS Struts书剑恩仇录

package com.redking.servlet;    

import java.io.IOException;    
import java.io.PrintWriter;    

import javax.servlet.ServletException;    
import javax.servlet.http.HttpServlet;    
import javax.servlet.http.HttpServletRequest;    
import javax.servlet.http.HttpServletResponse;    
import javax.servlet.http.HttpSession;    

import com.redking.dao.UserDao;    
import com.redking.dao.impl.UserDaoImpl;    
import com.redking.vo.User;    

public  class LoginServlet  extends HttpServlet {    

         /**    
         * Constructor of the object.    
         */    
         public LoginServlet() {    
                 super();    
        }    

         /**    
         * Destruction of the servlet. <br>    
         */    
         public  void destroy() {    
                 super.destroy();  // Just puts "destroy" string in log    
                 // Put your code here    
        }    

         /**    
         * The doGet method of the servlet. <br>    
         *    
         * This method is called when a form has its tag value method equals to get.    
         *    
         * @param request the request send by the client to the server    
         * @param response the response send by the server to the client    
         * @throws ServletException if an error occurred    
         * @throws IOException if an error occurred    
         */    
         public  void doGet(HttpServletRequest request, HttpServletResponse response)    
                         throws ServletException, IOException {    

                doPost(request,response);    
        }    

         /**    
         * The doPost method of the servlet. <br>    
         *    
         * This method is called when a form has its tag value method equals to post.    
         *    
         * @param request the request send by the client to the server    
         * @param response the response send by the server to the client    
         * @throws ServletException if an error occurred    
         * @throws IOException if an error occurred    
         */    
         public  void doPost(HttpServletRequest request, HttpServletResponse response)    
                         throws ServletException, IOException {    

                String username = request.getParameter( "username");    
                String password = request.getParameter( "password");    
                 /*    
                if(username!=null&&username.equals("redking")){    
                        request.setAttribute("username", username);    
                        request.getRequestDispatcher("/pages/successfull.jsp").forward(request, response);    
                }else{    
                        request.getRequestDispatcher("/pages/failure.jsp").forward(request, response);    
                }    
                */    
                UserDao dao =  new UserDaoImpl();    
                User u = dao.login(username, password);    
                HttpSession session = request.getSession();    
                 if(u!= null){    
                        session.setAttribute( "user", u);    
                        request.getRequestDispatcher( "/pages/successfull.jsp").forward(request, response);    
                } else{    
                        request.getRequestDispatcher( "/pages/failure.jsp").forward(request, response);    
                }    
        }    

         /**    
         * Initialization of the servlet. <br>    
         *    
         * @throws ServletException if an error occurs    
         */    
         public  void init()  throws ServletException {    
                 // Put your code here    
        }    

} 

package com.redking.util;    

public  interface SQLConstants {    
         public  static  final String USER_LOGIN_SQL =  " select id,username,password from UserTbl " +  " where username= ? and password = ? ";    
}