java定时任务的实现方法

import java.util.Timer;

import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;

public class SmsListener implements ServletContextListener{
    private Timer timer=null;

    public void contextDestroyed(ServletContextEvent sce) {
        timer.cancel();
    }

    public void contextInitialized(ServletContextEvent sce) {
        timer=new Timer(true);
　　　　　//设置任务计划，启动和间隔时间
        timer.schedule(new NoteReplyTask(), 0, 86400000);
    }

}

public class MyTask extends TimerTask {

  public void run() {
    // System.out.println("call at " + (new Date()));
    // TODO 此处添加具体任务代码
  }

}