关掉浏览器之后再打开，还能使购物车中的内容存在
HttpSession session = request.getSession();
String sessionid = session.getId();
Cookie cookie = new Cookie("JSESSIONID",sessionid);
cookie.setPath("/ShoppingWithSession");
cookie.setMaxAge(30*60);
response.addCookie(cookie);
session.setAttribute("name","洗衣机");