4. 获取ServletContext:            * ServletContext getServletContext()

package cn.itcast.web.request;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@WebServlet("/requestDemo10")
public class RequestDemo10 extends HttpServlet {

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {    ServletContext servletContext = request.getServletContext();    System.out.println(servletContext);}protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {    this.doPost(request,response);}

}