简易的购物车（增删改查）

package com.servlet; import java.io.IOException; import java.util.ArrayList; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; import com.bean.Book; import com.dao.BookDao; /** * Servlet implementation class ShoppingCart */ @WebServlet("/ShoppingCart") public class ShoppingCart extends HttpServlet { private static final long serialVersionUID = 1L; /** * @see HttpServlet#HttpServlet() */ public ShoppingCart() { super(); // TODO Auto-generated constructor stub } /** * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) */ protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub // response.getWriter().append("Served at: ").append(request.getContextPath()); /*String bookId = request.getParameter("bookId"); //获取session对象 HttpSession session = request.getSession(); //获取session中存储的购物车信息参数（bookList） ArrayList<Book> list = (ArrayList<Book>) session.getAttribute("bookList"); //判断购物车是否为空 if(null == list) { list = new ArrayList<>(); } Book book = new Book(); book.setBookId(Integer.parseInt(bookId.toString().trim())); list.add(book); //更新session中的购物车参数 session.setAttribute("bookList", list); System.out.println("&&&&&&&&&商品列表：" + list.toString() + "&&&&&&&&&&&&&"); //页面跳转会商品列表界面 response.sendRedirect("main.jsp"); */ /*HttpSession session = request.getSession(); ArrayList<Book> list = (ArrayList<Book>) session.getAttribute("bookList"); if(null == list) { list = new ArrayList<>(); } Book book = new Book(); book.setBookId(Integer.parseInt(bookId.toString().trim())); list.add(book); session.setAttribute("bookList", list);*/ String bookId = request.getParameter("bookId"); String bookName = request.getParameter("bookName"); String bookPrice = request.getParameter("bookPrice"); // HttpSession session = request.getSession(); // String bookId = (String)session.getAttribute("bookId"); int bookIdd = Integer.valueOf(bookId); // String bookName = (String)session.getAttribute("bookName"); // String bookPrice = (String)session.getAttribute("bookPrice"); double price = Double.parseDouble(bookPrice); BookDao bookdao = new BookDao(); boolean f1 = bookdao.add(bookIdd, bookName, price); if(f1) { request.getRequestDispatcher("MainServlet").forward(request, response); }else { request.setAttribute("errorMsg1", "添加失败"); } } /** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub doGet(request, response); } }