Servlet中怎么取得session和application

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletContext;//和其它的不在一个包
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

public class X extends HttpServlet {

 public void doGet(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException {
            HttpSession session=request.getSession();//得到session
         ServletContext    application =super.getServletContext();//GenericServlet提供的方法，得到application
 }

 

java.lang.Object  javax.servlet.GenericServlet     javax.servlet.http.HttpServlet