<listener>
    <listener-class>com.test.listener.Listener</listener-class>
  </listener>

import com.test.timmer.TimmerTest;

import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import java.util.Calendar;
import java.util.Timer;

public class Listener implements ServletContextListener {

  public void contextInitialized(ServletContextEvent sce) {
    System.out.println("啟動監(jiān)聽。。。。。。。。。。。。。。。。。");
    //定時器
    Timer timer = new Timer();
    //定時任務對象
    TimmerTest task = new TimmerTest();
    //指定到23:59:59
    Calendar calendar = Calendar.getInstance();
    calendar.set(Calendar.HOUR_OF_DAY,23);
    calendar.set(Calendar.MINUTE,59);
    calendar.set(Calendar.SECOND,59);
    //每天的23:59:59秒執(zhí)行任務，下次執(zhí)行延遲時長為24小時
    timer.schedule(task, calendar.getTime(), 24*60*60*1000);

  }

  public void contextDestroyed(ServletContextEvent sce) {

  }
}

package com.test.timmer;

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.TimerTask;

public class TimmerTest extends TimerTask {

  public void run() {
    Date dt = new Date();
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy年MM月dd日 HH時mm分ss秒");
    System.out.println(sdf.format(new Date())+",執(zhí)行定時任務");
  }
}