1）创建Cookie：
Cookie cookie = new Cookie(String cookieName,String cookieValue);
示例：
Cookie cookie = new Cookie("username"，"zhangsan");
设置Cookie在客户端的持久化时间：cookie.setMaxAge(10*60);
3）设置Cookie的携带路径：
cookie.setPath("/");
response.addCookie(Cookie cookie);
1．获得Session对象
HttpSession session = request.getSession();
session.setAttribute(String name,Object obj);
session.getAttribute(String name);
session.removeAttribute(String name);