package com.learn;

import javax.servlet.ServletContext;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import java.io.*;

/**
 * Created by Administrator on 2017/09/23.
 */
public class MyServletContextListener implements ServletContextListener {
 @Override
 public void contextInitialized(ServletContextEvent sce) {

  System.out.println("Webapp initital.......");
  ServletContext servletContext = sce.getServletContext();
  InputStreamReader inputStreamReader = new InputStreamReader(servletContext.getResourceAsStream("/count/count.txt"));
  BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
  try {
   int icount = Integer.parseInt(bufferedReader.readLine());
   icount++;
   servletContext.setAttribute("count",icount);
   System.out.println("Webapp initital success");
  } catch (IOException e) {
   e.printStackTrace();
  }

 }

 @Override
 public void contextDestroyed(ServletContextEvent sce) {

  System.out.println("webApp destroyed ........");
  ServletContext servletContext = sce.getServletContext();

  Integer count = (Integer) servletContext.getAttribute("count");
  if(count != null){
   count ++;
   String filePath = servletContext.getRealPath("/count");
   filePath = filePath+"/count.txt";
   try {
    PrintWriter printWriter = new PrintWriter(filePath);
    printWriter.write(count);
    printWriter.close();
    System.out.println("webApp desdroyed success ");
   } catch (FileNotFoundException e) {
    e.printStackTrace();
   }
  }
 }
}

package com.learn;

import javax.servlet.http.HttpSession;
import javax.servlet.http.HttpSessionEvent;
import javax.servlet.http.HttpSessionListener;

/**
 * Created by Administrator on 2017/09/23.
 */
public class MySessionListener implements HttpSessionListener{
 @Override
 public void sessionCreated(HttpSessionEvent se) {

  HttpSession session = se.getSession();
  System.out.println("新建session，sessionId："+session.getId());

 }

 @Override
 public void sessionDestroyed(HttpSessionEvent se) {
  HttpSession session = se.getSession();
  System.out.println("销毁session，sessionId："+session.getId());
 }
}

package com.learn;

import javax.servlet.ServletRequestEvent;
import javax.servlet.ServletRequestListener;
import javax.servlet.http.HttpServletRequest;

/**
 * Created by Administrator on 2017/09/23.
 */
public class MyRequestListener implements ServletRequestListener {
 @Override
 public void requestDestroyed(ServletRequestEvent sre) {


  HttpServletRequest request = (HttpServletRequest) sre.getServletRequest();
  Long date = System.currentTimeMillis()-(Long) (request.getAttribute("dateCreated"));
  System.out.println("消耗时间："+date);
 }

 @Override
 public void requestInitialized(ServletRequestEvent sre) {
  HttpServletRequest request = (HttpServletRequest) sre.getServletRequest();
  String uri = request.getRequestURI();
  uri = request.getQueryString() == null ? uri : (uri + "?" + request.getQueryString());

  request.setAttribute("dateCreated", System.currentTimeMillis());
  System.out.println("IP:"+request.getRemoteAddr()+"URI:"+uri);

 }
}

<listener>
  <listener-class>com.learn.MyServletContextListener</listener-class>
</listener>

<listener>
  <listener-class>com.learn.MySessionListener</listener-class>
</listener>

<listener>
 <listener-class>com.learn.MyRequestListener</listener-class>
</listener>