session 购物车

package session;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

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 SessionDemo4 extends HttpServlet {

   protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
       String id = request.getParameter("id");
       Book book = (Book)Db.getAll().get(id);

       HttpSession session = request.getSession();
       //当前网站名，不能够手动指定而是，通过下面的方法获得
//       request.getContextPath();

       //从Session的到用户用于保存所有书的集合（购物车）
       List list = (List) session.getAttribute("list");
       if(list == null){
           list = new ArrayList();
           session.setAttribute("list", list);
       }
       list.add(book);

       //重定向到购物车显示页面
       response.sendRedirect(request.getContextPath()+"/ListCarServlet");
   }

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
}

巴特西

session 购物车

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