java|java session 保存买过的商品信息 javasession保存买过的商品信息

上代码
商品的信息

/** *所有商品的信息 */ public class ShappingLists extends HttpServlet {protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html; charset=UTF-8"); PrintWriter out = response.getWriter(); request.getSession(); //创建session out.write("本网站有如下书： "); //展示数据 Set set = DB.getAll().entrySet(); for(Map.Entry me : set){ Book book = me.getValue(); String url = "/Demo2/BuyProductsServlet?id=" + book.getId(); //给url带上sessionId防止浏览器禁用cookies url = response.encodeURL(url); out.println(book.getName()+ "购买 "); } }protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {doGet(request, response); }}

点击了后进入的存session的界面（过度的界面）

/** * 购买商品的具体界面 */ public class BuyProductsServlet extends HttpServlet { protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {String id = request.getParameter("id"); Book book = (Book) DB.getAll().get(id); //得到用户想买的书HttpSession session = request.getSession(); List list = (List) session.getAttribute(ShappingListServlet.session_key); //得到用户用于保存所有书的容器 if(list==null){ list = new ArrayList(); session.setAttribute(ShappingListServlet.session_key, list); } list.add(book); //服务器跳转的方法 //request.getRequestDispatcher("/servlet/ListCartServlet").forward(request, response); //浏览器的跳转 String url = response.encodeRedirectURL("/Demo2/ShappingListServlet"); System.out.println(url); response.sendRedirect(url); } protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); }}

展示够买过的商品信息

/** *利用 session 显示购买过的商品 */ public class ShappingListServlet extends HttpServlet {/** * session 是服务端的技术当用户点击了购买商品后在本地记录下该商品的信息。挑战到购买界面后进行展示商品的信息 * * 注意一个会话只会保存一份serssion但是 ie8除外，ie8不管是打开几个浏览器都是保存的一个serssion */public static final String session_key="list"; protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html; charset=UTF-8"); PrintWriter out = response.getWriter(); //显示用户购买过的商品 out.write("你购买过的商品有: "); HttpSession session=request.getSession(); List list=(List) session.getAttribute(session_key); if(list==null||list.size()==0) { out.write("您还没有买过什么商品呢"); return; }for (Book book : list) { out.write("商品有"+book.getName()+" "); }}protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); }//模拟数据库 public static class DB { //有序的 map public static LinkedHashMap map=new LinkedHashMap(); static { //静态代码块用于初始化 map的信息 map.put("1", new Book("1","javaweb开发","老张","一本好书")); map.put("2", new Book("2","spring开发","老黎","一本好书")); map.put("3", new Book("3","hibernate开发","老佟","一本好书")); map.put("4", new Book("4","struts开发","老毕","一本好书")); map.put("5", new Book("5","ajax开发","老张","一本好书")); }public static Map getAll(){ return map; } }//商品的信息 public static class Book { private String id; private String name; private String author; //作者 private String description; //描述public Book() { super(); // TODO Auto-generated constructor stub } public Book(String id, String name, String author, String description) { super(); this.id = id; this.name = name; this.author = author; this.description = description; } public String getId() { return id; } public void setId(String id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getAuthor() { return author; } public void setAuthor(String author) { this.author = author; } public String getDescription() { return description; } public void setDescription(String description) { this.description = description; } } }

【java|java session 保存买过的商品信息】星期六过去了晚安了