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网站设计规划高中信息技术,wordpress4.7.2卡,网站优化自己可以做吗,上街做网站查看全文#xff1a;https://www.longkui.site/program/java/idea2020sevletsession3/7204/ 【任务目标】 通过所学Session知识以及购物车的访问流程#xff0c;以购买蛋糕为例#xff0c;模拟实现购物车功能。 1.创建实体类 先创建一个文件夹#xff0c;名称为cn.itcast…查看全文https://www.longkui.site/program/java/idea2020sevletsession3/7204/【任务目标】通过所学Session知识以及购物车的访问流程以购买蛋糕为例模拟实现购物车功能。1.创建实体类先创建一个文件夹名称为cn.itcast.session.entity然后右击 entity文件夹选择New—Java Class名字为Cake代码参考如下package cn.itcast.session.entity;public class Cake{private static final long serialVersionUID1L;private Stringid;private String name;publicCake(){}public Cake(String id, String name){this.idid;this.namename;}public StringgetId(){returnid;}public void setId(Stringid){this.idid;}public StringgetName(){returnname;}public void setName(String name){this.namename;}}然后再在entity文件下创建一个数据库模拟类CakeDB代码参考如下package cn.itcast.session.entity;importjava.util.Collection;importjava.util.LinkedHashMap;importjava.util.Map;public class CakeDB{private static MapString, Cakecakenew LinkedHashMapString, Cake();static{cake.put(1, new Cake(1,A类蛋糕));cake.put(2, new Cake(2,B类蛋糕));cake.put(3, new Cake(3,C类蛋糕));cake.put(4, new Cake(4,D类蛋糕));cake.put(5, new Cake(5,E类蛋糕));}// 获得所有的蛋糕 public static CollectionCakegetAll(){returncake.values();}// 根据指定的id获蛋糕 public static Cake getCake(Stringid){returncake.get(id);}}创建完后如下2.创建Servlet类首先创建第一个Servlet类用于展示所有可购买蛋糕的列表通过点击 ”点击购买“按钮便可以将指定蛋糕添加到购物车中。先新建一个文件夹右击session文件夹选择New—package名称为 servlet然后右击 servlet选择New—Create New Servlet名字为ListCakeServlet代码参考如下package cn.itcast.session.servlet;importcn.itcast.session.entity.Cake;importcn.itcast.session.entity.CakeDB;importjava.io.*;importjava.util.Collection;importjavax.servlet.ServletException;importjavax.servlet.annotation.WebServlet;importjavax.servlet.http.*;WebServlet(nameListCakeServlet,urlPatterns/ListCakeServlet)public class ListCakeServlet extends HttpServlet{private static final long serialVersionUID1L;public void doGet(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException{resp.setContentType(text/html; charsetutf-8);PrintWriter outresp.getWriter();CollectionCakecakesCakeDB.getAll();out.write(本站提供的蛋糕有br);for(Cake cake:cakes){String urlPurchaseServlet?id cake.getId();out.write(cake.getName()a href url 点击购买/abr);}}}再创建一个servlet名字为PurchaseServletpackage cn.itcast.session.servlet;importcn.itcast.session.entity.Cake;importcn.itcast.session.entity.CakeDB;importjava.io.IOException;importjava.util.*;importjavax.servlet.ServletException;importjavax.servlet.annotation.WebServlet;importjavax.servlet.http.*;WebServlet(namePurchaseServlet,urlPatterns/PurchaseServlet)public class PurchaseServlet extends HttpServlet{private static final long serialVersionUID1L;public void doGet(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException{// 获得用户购买的商品 Stringidreq.getParameter(id);if(idnull){// 如果id为null重定向到ListBookServlet页面 String urlListBookServlet;resp.sendRedirect(url);return;}Cake bookCakeDB.getCake(id);// 创建或者获得用户的Session对象 HttpSession sessionreq.getSession();// 从Session对象中获得用户的购物车 ListCakecart(List)session.getAttribute(cart);if(cartnull){// 首次购买为用户创建一个购物车(List集合模拟购物车)cartnew ArrayListCake();// 将购物城存入Session对象 session.setAttribute(cart, cart);}// 将商品放入购物车 cart.add(book);// 创建Cookie存放Session的标识号 Cookie cookienew Cookie(JSESSIONID, session.getId());cookie.setMaxAge(60*30);cookie.setPath(/Servlet);resp.addCookie(cookie);// 重定向到购物车页面 String urlCartServlet;resp.sendRedirect(url);}}最后创建一个Servlet名字为CartServletpackage cn.itcast.session.servlet;importcn.itcast.session.entity.Cake;importjava.io.*;importjava.util.List;importjavax.servlet.ServletException;importjavax.servlet.annotation.WebServlet;importjavax.servlet.http.*;WebServlet(nameCartServlet,urlPatterns/CartServlet)public class CartServlet extends HttpServlet{public void doGet(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException{resp.setContentType(text/html;charsetutf-8);PrintWriter outresp.getWriter();// 变量cart引用用户的购物车 ListCakecartnull;// 变量pruFlag标记用户是否买过商品 boolean purFlagtrue;// 获得用户的session HttpSession sessionreq.getSession(false);// 如果session为nullpurFlag置为falseif(sessionnull){purFlagfalse;}else{// 获得用户购物车 cart(List)session.getAttribute(cart);// 如果用的购物车为nullpurFlag置为falseif(cartnull){purFlagfalse;}}/* * 如果purFlag为false表明用户没有购买蛋糕 重定向到ListServlet页面 */if(!purFlag){out.write(对不起您还没有购买任何商品br);}else{// 否则显示用户购买蛋糕的信息 out.write(您购买的蛋糕有br);double price0;for(Cake cake:cart){out.write(cake.getName()br);}}}}创建完后如下3.测试效果先访问蛋糕列表http://localhost:8080/Servlet01_war_exploded/ListCakeServlet后续查看全文https://www.longkui.site/program/java/idea2020sevletsession3/7204/