listproductaction.java

这是一个购物车的源码

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){
				//疑问：根本就没有分配Session,哪来的？
				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;
	}
}