addfoodtocart.java

订餐系统

package Biz;

import java.util.*;

import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import Entities.*;

public class AddFoodToCart implements BizInterface{

	public String execute(HttpServletRequest request,HttpServletResponse response)
	{
		
		String path = "viewCart.jsp";
		HttpSession session = request.getSession(false);
		
		//如果session不存在，则转向show.jsp
		
		if(session == null)
		{
			path = "show.jsp";
		}
		
		FoodBean food = (FoodBean) session.getAttribute("foodToAdd");
		
		//取出购物车中添加的餐品
		Map cart = (Map) session.getAttribute("cart");
		
		//如果购物车中不存在，则创建购物车
		if(cart == null)
		{
			cart = new HashMap();
			//将购物车存入session之中
			session.setAttribute("cart",cart);
		}
		//判断餐品是否在购物车中
		CartItemBean cartItem = (CartItemBean) cart.get(food.getFoodID());
		//如果餐品在购物车中，则更新其数量
		//否则，创建一个条目到Map中
		if(cartItem != null)
		{
			cartItem.setQuantity(cartItem.getQuantity()+1);
		}
		else
		{
			//如果购物车中不存在欲添加的书籍，就添加该书籍，并设置数量为1
			cart.put(food.getFoodID(),new CartItemBean(food,1));
		}
	
		return path;
	}
}