addbooktocart.java

主要是用net开发的 用mvc模式 有酒店管理

/*
 * y2javaee.sg.ch04.AddBookToCart.java
 * Y2javaee的ch04示例，演示购物车
 */
package com.apache.servlet;

import java.io.IOException;
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.apache.pojo.BookBean;
import com.apache.pojo.CartItemBean;

public class AddBookToCart extends HttpServlet {

	private static final long serialVersionUID = 1L;

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

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

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

	
	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		response.setContentType("text/html;charset=gbk");
		request.setCharacterEncoding("gbk");
		HttpSession session=request.getSession(false);
		RequestDispatcher dispatcher;

		// 如果session不存在，转向books.jsp
		if (session == null) {
			dispatcher = request.getRequestDispatcher("books.jsp");
			dispatcher.forward(request, response);
		}
		// 取出购物车和添加的书籍
		Map cart = (Map) session.getAttribute("cart");
		BookBean book = (BookBean) session.getAttribute("bookToAdd");
			// 如果购物车不存在，创建购物车
		if (cart == null) {
			cart = new HashMap();
			// 将购物车存入session之中
			session.setAttribute("cart", cart);
		}
		// 判断书籍是否在购物车中
		
		CartItemBean cartItem = (CartItemBean)cart.get(book.getISBN());
		
                
		// 如果书籍在购物车中，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
			cart.put(book.getISBN(), new CartItemBean(book, 1));
    //将所有书籍放入session中
      session.setAttribute("books",cart.values().toArray());
      System.out.println(cart.values().toArray().length);
		
      // 转向viewCart.jsp显示购物车
		dispatcher = request.getRequestDispatcher("/viewCart.jsp");
		
		dispatcher.forward(request, response);
		

	}

	public void init() throws ServletException {
		// Put your code here
	}

}