java 定时操作

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.TimerTask;
public class TimerDemo extends TimerTask{
    public void run(){
        SimpleDateFormat sdf=null;
        sdf=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss:SSS");
        System.out.println(sdf.format(new Date()));
    }
}

import java.util.Timer;
public class TestTask {
    public static void main(String[] args) {
        Timer t=new Timer();
        TimerDemo td=new TimerDemo();
        t.schedule(td, 1000,2000);
    }
}