java - 定期执行线程并在满足条件或时间结束后停止它

Question

我想定期执行一个线程来检查某个文件是否准备好上传，并在准备好后立即上传，然后立即停止线程。另外，如果已经过去很长一段时间，我想停止线程，无论文件尚未准备好，但不能在 run 方法本身内部执行此操作。

    final ScheduledFuture<?> fileUploadedFuture = scheduler.scheduleAtFixedRate(() -> {
        try {
            if (fileReady("xyz.txt")) {
                uploadFile("xyz.txt")
                //cancel fileUploadedFuture and fileUploadedFutureCanceller
            }
        } catch (Exception e) {
            throw new ServiceException(e);
        }
    }, 0, delay, TimeUnit.SECONDS);

    final ScheduledFuture<?> fileUploadedFutureCanceller = scheduler.schedule(() -> {
        fileUploadedFuture.cancel(true);
    }, 60, TimeUnit.SECONDS);
}

Answer 1

使用 ScheduledThreadPoolExecutor 怎么样？

public class TestExecutor {
    private static ScheduledThreadPoolExecutor exec = new ScheduledThreadPoolExecutor(1);

    private static class PushFile implements Runnable {
        @Override
        public void run() {
            if (new File("test.txt").exists()) {
                System.out.println("found it!");
                exec.shutdown();
            } else {
                System.out.println("waiting");
            }
        }

    }

    private static class ShutMeDown implements Runnable {
        @Override
        public void run() {
            System.out.println("timeout");
            exec.shutdown();
        }
    }

    public static void main(String[] args) {
        exec.scheduleWithFixedDelay(new PushFile(), 0, 1, TimeUnit.SECONDS);
        exec.scheduleWithFixedDelay(new ShutMeDown(), 10, 1, TimeUnit.SECONDS);
    }
}