java ScheduledExecutorService执行周期任务

1.schedule 
     schedule(Runnable command, long delay, TimeUnit unit)，schedule方法被用来延迟指定时间后执行某个指定任务。

public class Job implements Runnable {
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");

    public void run() {
        try {
            Thread.sleep(5000);
        } catch (InterruptedException ex) {
            ex.printStackTrace();
        }
        System.out.println("do something  at:" + sdf.format(new Date()));
    }
}

public class ScheduledExecutorServiceTest {

    public static void main(String[] args) {
        ScheduledExecutorService schedule = Executors.newScheduledThreadPool(5);
        final SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
        System.out.println(" begin to do something at:" + sdf.format(new Date()));
        schedule.schedule(new Job(),1, TimeUnit.SECONDS);
    }
}

 输出如下：

  begin to do something at:2012-08-03 09:31:36
  do something  at:2012-08-03 09:31:42

 

2.scheduleWithFixedDelay 

         scheduleWithFixedDelay(Runnable command, long initialDelay, long delay,TimeUnit unit)

        scheduleWithFixedDelay()：安排所提交的Runnable任务在每次执行完后，等待delay所指定的时间后重复执行
         创建并执行一个在给定初始延迟后首次启用的定期操作，随后，在每一次执行终止和下一次执行开始之间都存在给定的延迟，如果任务的执行时间超过了廷迟时间（delay），下一个任务则会在
（当前任务执行所需时间+delay）后执行。

public class ScheduledExecutorServiceTest {
        public static void main(String[] args) {
            ScheduledExecutorService schedule = Executors.newScheduledThreadPool(5);
            final SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
            System.out.println(" begin to do something at:" + sdf.format(new Date()));
            schedule.scheduleWithFixedDelay(new Job(), 1, 2, TimeUnit.SECONDS);
        }
    }

 输出如下：

    begin to do something at:2012-08-03 09:36:53
    do something at:2012-08-03 09:36:59
    do something at:2012-08-03 09:37:06
    do something at:2012-08-03 09:37:13

 

3.scheduleAtFixedRate 
         scheduleAtFixedRate(Runnable command, long initialDelay, long period, TimeUnitunit)

         scheduleAtFixedRate()：安排所提交的Runnable任务按指定的间隔重复执行
         创建并执行一个在给定初始延迟后首次启用的定期操作，后续操作具有给定的周期；也就是将在 initialDelay 后开始执行，然后在initialDelay+period 后执行，接着在 initialDelay + 2 * period 后执行，依此类推。
如果任务的执行时间小于period，将会按上述规律执行。否则，则会按 任务的实际执行时间进行周期执行。

public class ScheduledExecutorServiceTest {

    public static void main(String[] args) {
        ScheduledExecutorService schedule = Executors.newScheduledThreadPool(2);
        final SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
        System.out.println(" begin to do something at:" + sdf.format(new Date()));
        schedule.scheduleAtFixedRate(new Job(), 1,2, TimeUnit.SECONDS);
    }

 结果输出：

    begin to do something at:2012-08-04 08:53:30
    do something at:2012-08-04 08:53:36
    do something at:2012-08-04 08:53:41
    do something at:2012-08-04 08:53:46
    do something at:2012-08-04 08:53:51

 

Demo:

int a = 0;
	int b = 0;
	ScheduledExecutorService mExecutorService;
	ScheduledFuture mFuture1, mFuture2;

	private void executScheduledExecutorService() {
		mExecutorService = Executors.newScheduledThreadPool(1);
		mFuture1 = mExecutorService.scheduleAtFixedRate(new EchoServer(), 1000, 1000, TimeUnit.MILLISECONDS);

		mExecutorService.schedule(new Runnable() {

			@Override
			public void run() {
				// TODO Auto-generated method stub
				Log.i("W", "shut down.");
				mExecutorService.shutdownNow();
			}
		}, 40, TimeUnit.SECONDS);

	}

	class EchoServer implements Runnable {
		@Override
		public void run() {
			// TODO Auto-generated method stub
			a++;
			Log.i("W", "a = " + a);
			if (a == 10) {
				mFuture1.cancel(false);
			}
			if (a == 2) {
				mFuture2 = mExecutorService.scheduleAtFixedRate(new EchorServer(), 1000, 2000, TimeUnit.MILLISECONDS);
			}
		}
	}

	class EchorServer implements Runnable {

		@Override
		public void run() {
			// TODO Auto-generated method stub
			b++;
			Log.i("W", "b = " + b);
			if (b == 15) {
				mFuture2.cancel(false);
			}
		}
	}

 

 

 

转载：http://kim-miao.iteye.com/blog/1618713