package cnitcastsessionServlet;import cnitcastsessionentityCake;import cnitcastsessionentityCakeDB;import javaio;import javautilCollection;import javaxservletannotationWebServlet;import javaxservletSe

的功能实现：

package cn.itcast.session.Servlet; import cn.itcast.session.entity.Cake; import cn.itcast.session.entity.CakeDB; import java.io.; import java.util.Collection; import javax.servlet.annotation.WebServlet; import javax.servlet.ServletException; import javax.servlet.http.; @WebServlet(name = "ListCakeServlet",urlPatterns="/ListCakeServlet") public class ListCakeServlet extends HttpServlet { private static final long serialVersionUID = 1L; public void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { resp.setContentType("text/html;charset=utf-8"); PrintWriter out = resp.getWriter(); Collection cakes = CakeDB.getAll(); out.write("本站提供的蛋糕有：
"); for (Cake cake : cakes) { String url = "PurchaseServlet?id=" + cake.getId(); out.write(cake.getName() + "点击购买
"); } HttpSession session = req.getSession(); Collection cart = (Collection) session.getAttribute("cart"); if (cart != null && cart.size() > 0) { out.write("
您已经选购了以下商品：
"); for (Cake cake : cart) { out.write(cake.getName() + "
"); } } }