session可以通过request.getSession();来获取

application可以通过this.getServletContext() 或 request.getSession.getServletContext()来获取

1 public class ServletTest extends HttpServlet {2     public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {3         HttpSession session =  request.getSession();4         ServletContext application = this.getServletContext();5     }6 }