controllerservlet.java

java三层架构（MVC)实现的在线图书销售系统。其中应用到工厂

package accp.yyw.control;

import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;
import accp.yyw.model.command.*;
/**
 * <p>Title: BookShop</p>
 * <p>Description: </p>
 * <p>Copyright: Copyright (c) 2005</p>
 * <p>Company: accp</p>
 * @author yyw
 * @version 1.0
 */


public class ControllerServlet extends HttpServlet {

          RequestAction requestaction = null;
          SessionAction sessionaction = null;

          public void init(ServletConfig config) throws ServletException {

                  super.init(config);

                  requestaction = new RequestAction();
                  sessionaction = new SessionAction();
          }

          public void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {

            processRequest(request,response);
          }

          public void doPost(HttpServletRequest request,HttpServletResponse response)throws ServletException, IOException {

            processRequest(request,response);
          }

          public void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException,IOException {

                  HttpSession session = request.getSession();

                  String dispatcher = null;

                  if(session.getAttribute("exister")==null){

                    //dispatcher = processRequestAction(request,response);
                    dispatcher = processSessionAction(request,response);
                  }
                  else{

                    dispatcher = processSessionAction(request,response);
                  }

                  if(dispatcher==null){

                          dispatcher = processSessionAction(request,response);
                  }

                  RequestDispatcher requestdispatcher = request.getRequestDispatcher(dispatcher);
            requestdispatcher.forward(request,response);
          }

          public String processRequestAction(HttpServletRequest request, HttpServletResponse response) throws ServletException,IOException {

                  String cmd = request.getParameter("cmd");

                  String dispatcher = null;

                  if(cmd!=null&&cmd.equals("bookshop")){dispatcher = requestaction.nullAction(request);}
                  if(cmd==null){dispatcher = requestaction.nullAction(request);}

                   return dispatcher;
          }

          public String processSessionAction(HttpServletRequest request, HttpServletResponse response) throws ServletException,IOException {

                   String cmd = request.getParameter("cmd");

                   String dispatcher = null;

                   if(cmd==null||cmd.endsWith("null")){dispatcher = sessionaction.nullAction(request);}

                   if(cmd!=null&&cmd.equals("insertmember")){dispatcher = sessionaction.insertmember(request);}

                  return dispatcher;
          }

          public void destroy() {

          }
}