Servlet中怎麼取得session和application

import java.io.IOException; import java.io.PrintWriter;   import javax.servlet.ServletContext;//和其它的不在一個包 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  }