package com.tarena.shoppingcart.action;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.HttpSession;import java.util.*;import com.tarena.shoppingcart.entity.*;import com.tarena.shoppingcart.dao.ShoppingCartHibernateImpl;import org.apache.struts.action.*;public class ListProductAction extends Action {	public ActionForward execute(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws Exception {		ActionForward forward=null;		ShoppingCartHibernateImpl service=new ShoppingCartHibernateImpl();		try{			List list=(List)service.listProducts();			Cart cart=new Cart();			if(list!=null){				//疑問：根本就沒有分配Session,哪來的？				HttpSession session=request.getSession(false);				if(session.getAttribute("cart")==null){					session.setAttribute("cart",cart);				}				session.setAttribute("products",list);				forward=mapping.findForward("list");			}		}catch(Exception e){			e.printStackTrace();			forward=mapping.findForward("error");		}		return forward;	}}