addbooktocart.java

jsp/servlet/javaBean应用：网上购书系统

package servlet;

import java.io.*;

import javax.servlet.*;
import javax.servlet.http.*;

import java.util.*;
import bean.*;

public class AddBookToCart extends HttpServlet {

	/**
	 * 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
	}

	/**
	 * The doGet method of the servlet. <br>
	 *购物车
	 * 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");
		PrintWriter out = response.getWriter();
		request.setCharacterEncoding("GBK");
		
		HttpSession session=request.getSession(false);
		if(session==null){
			request.getRequestDispatcher("../chJsp/books.jsp").forward(request, response);
			return;
		}
		BookBean bookbean=(BookBean)session.getAttribute("bookToAdd");
		
		Map cart=(Map)session.getAttribute("cart");
		if(cart==null){
			cart=new HashMap();
			session.setAttribute("cart",cart);
		}
		
		CartItemBean cartItem=(CartItemBean)cart.get(bookbean.getIsbn());
		if(cartItem!=null){
			cartItem.setQuantity(cartItem.getQuantity()+1);
		}else{
			cart.put(bookbean.getIsbn(),new CartItemBean(bookbean,1));
			request.getRequestDispatcher("../chJsp/viewCart.jsp").forward(request, response);
		}
		out.flush();
		out.close();
	}

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

}