addfoodtocart.java

贯穿案例JSP+JavaBean+Servlet网上订餐系统.希望大家下载下来研究

package com.restrant.servlet;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import com.restrant.entity.CartItemBean;
import com.restrant.entity.FoodBean;

public class AddFoodToCart extends HttpServlet {

	/**
	 * Constructor of the object.
	 */
	public AddFoodToCart() {
		super();
	}

	/**
	 * Destruction of the servlet. <br>
	 */
	public void destroy() {
		super.destroy(); // Just puts "destroy" string in log
		// Put your code here
	}

	/**
	 * The doGet method of the servlet. <br>
	 *
	 * This method is called when a form has its tag value method equals to get.
	 * 
	 * @param request the request send by the client to the server
	 * @param response the response send by the server to the client
	 * @throws ServletException if an error occurred
	 * @throws IOException if an error occurred
	 */
	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		response.setContentType("text/html");
		request.setCharacterEncoding("GBK");
		HttpSession session =request.getSession(false);
		String id=request.getParameter("id");
		if(id!=null){
			int foodid=Integer.parseInt(id);
			List<FoodBean> foodList = (List<FoodBean>) session
			.getAttribute("FoodList");

			for (int i = 0; i < foodList.size(); i++) {
				FoodBean currentfood = (FoodBean) foodList.get(i);
				if (currentfood.getFoodId() == foodid) {
					session.setAttribute("foodToAdd", currentfood);
				break;	
				}}
		}
		Map cart=(Map)session.getAttribute("cart");
		FoodBean food=(FoodBean)session.getAttribute("foodToAdd");
		RequestDispatcher dispatcher;
		if(cart==null){
			cart=new HashMap();
			session.setAttribute("cart", cart);
			
		}
		CartItemBean cartItem=(CartItemBean)cart.get(food.getFoodId());
	if(cartItem!=null){
		cartItem.setQuantity(cartItem.getQuantity()+1);
	}else{
		cart.put(food.getFoodId(), new CartItemBean(food,1));

		
//		dispatcher=request.getRequestDispatcher("/ch01/shopcart.jsp");
//		dispatcher.forward(request, response);
	}response.sendRedirect("/restrant/ch01/shopcart.jsp");
	}

	/**
	 * The doPost method of the servlet. <br>
	 *
	 * This method is called when a form has its tag value method equals to post.
	 * 
	 * @param request the request send by the client to the server
	 * @param response the response send by the server to the client
	 * @throws ServletException if an error occurred
	 * @throws IOException if an error occurred
	 */
	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

	doGet(request,response);
	}

	/**
	 * Initialization of the servlet. <br>
	 *
	 * @throws ServletException if an error occurs
	 */
	public void init() throws ServletException {
		// Put your code here
	}

}