定時調度器主要是負責一些定時任務的調度，

public class CronTaskPool {

    /**
     * 執行任務的線程池
     */
    private Executor executor;

    /**
     * 調度任務的線程池
     */
    private ScheduledExecutorService scheduled;

    private CronTaskPool() {
    }

    public static CronTaskPool newCornTaskPool(int poolSize, String poolName) {
        CronTaskPool taskPool = new CronTaskPool();
        taskPool.executor = ThreadPools.newFixedThreadPool(poolName, poolSize);
        taskPool.scheduled = ThreadPools.newSingleThreadScheduledExecutor("scheduled-" + poolName);
        return taskPool;
    }

    /**
     * 收到任務后計算距離下一次執行的時間，提交至ScheduledExecutorService中
     */
    public void submit(CronTask cronTask) {
        scheduled.schedule(() -> safeExec(cronTask), getNextDelay(cronTask.getCron()),
            TimeUnit.MILLISECONDS);
    }

    /**
     * 將Cron中的任務提交至Executor執行，生成下一個任務
     */
    private void safeExec(CronTask cronTask) {
        try {
            executor.execute(cronTask.getRunnable());
            submit(cronTask);
        } catch (Exception e) {

        }
    }

    /**
     * 計算當前時間距離下次執行的間隔
     */
    private long getNextDelay(CronSequenceGenerator corn) {
        return corn.next(new Date()).getTime() - System.currentTimeMillis();
    }

    private static void safeSleep(int seconds) {
        try {
            Thread.sleep(1000L * seconds);
        } catch (Throwable t) {

        }
    }

    public static void main(String[] args) {
        CronTaskPool taskPool = CronTaskPool.newCornTaskPool(1, "test");
        taskPool.submit(new CronTask() {
            @Override
            public Runnable getRunnable() {
                return () -> System.out.println(System.currentTimeMillis());
            }

            @Override
            public CronSequenceGenerator getCron() {
                return new CronSequenceGenerator("*/5 * * * * ?");
            }
        });

        safeSleep(100);
    }
}

public interface CronTask {

    /**
     * 要被定時調度的任務
     */
    Runnable getRunnable();

    /**
     * 任務調度的頻率，該類存在于org.springframework.scheduling.support.CronSequenceGenerator
     * 接受一個cron表達式
     */
    CronSequenceGenerator getCron();
}