java scheduledexecutor 每小时,java – ScheduledExecutorService任务的运行时间...

我定期运行任务并为间隔提供灵活性,下一个超时在每个任务结束时计算,从Instant.now()转换为毫秒,并使用ScheduledExecutorService#schedule进行调度.

这段代码通常工作正常(左边的蓝色曲线),但其他日子则不太好.

在我看来,事情有时会在启动时变坏(机器每晚重启),虽然程序应该并且确实纠正自己,但ScheduledExecutorService#schedule不能恢复,并且计划任务一直运行得很晚.似乎完整的JVM重启是唯一的解决方案.

我最初的想法是,这是一个错误,根据机器启动的时间,事情可能会出错.但是以下日志输出表明该问题与我对ScheduledExecutorService#schedule的使用有关：

// Log time in GMT+2, other times are in GMT

// The following lines are written following system startup (all times are correct)

08 juin 00:08:49.993 [main] WARN com.pgscada.webdyn.Webdyn - Scheduling next webdyn service time. Currently 2018-06-07T22:08:49.993Z, last connection null

08 juin 00:08:50.586 [main] INFO com.pgscada.webdyn.Webdyn - The next data sample at 2018-06-07T22:10:00Z and the next FTP connection at 2018-06-07T22:30:00Z

08 juin 00:08:50.586 [main] WARN com.pgscada.webdyn.Webdyn - Completed webdyn schedule in 9ms, next execution at 2018-06-07T22:10:00Z (in 69414 ms) will run as data-sample

// So we are expecting the next execution to occur at 00:10:00 (or in 69.4 seconds)

// Except that it runs at 00:11:21

08 juin 00:11:21.206 [pool-1-thread-4] INFO com.pgscada.webdyn.Webdyn - Executing Webdyn service, isDataSample=true, isFtpConnection=false, nextTimeout=2018-06-07T22:10:00Z, lastFtpConnection=null

// But thats OK because it should correct itself

08 juin 00:13:04.151 [pool-1-thread-4] WARN com.pgscada.webdyn.Webdyn - Scheduling next webdyn service time. Currently 2018-06-07T22:10:00Z, last connection null

08 juin 00:13:04.167 [pool-1-thread-4] INFO com.pgscada.webdyn.Webdyn - The next data sample at 2018-06-07T22:20:00Z and the next FTP connection at 2018-06-07T22:30:00Z

08 juin 00:13:04.167 [pool-1-thread-4] WARN com.pgscada.webdyn.Webdyn - Completed webdyn schedule in 0ms, next execution at 2018-06-07T22:20:00Z (in 415833 ms) will run as data-sample

// So now we are expecting the next execution to occur at 00:20:00 (or in 415.8 seconds)

// But it runs at 00:28:06

08 juin 00:28:06.145 [pool-1-thread-4] INFO com.pgscada.webdyn.Webdyn - Executing Webdyn service, isDataSample=true, isFtpConnection=false, nextTimeout=2018-06-07T22:20:00Z, lastFtpConnection=null

以下是调度功能的实际生产代码.

ScheduledExecutorService EXECUTORS = Executors.newScheduledThreadPool(10);

private void scheduleNextTimeout(Instant currentTime, Instant lastFtpConnection) {

try {

log.info("Scheduling next webdyn service time. Currently {}, last connection {}", currentTime, lastFtpConnection);

// Parse config files first

getConfigIni().parse();

long time = System.nanoTime();

final Instant earliestPossibleTimeout = Instant.now().plusSeconds(5);

Instant nextDataSample = nextTimeout(currentTime);

if (nextDataSample.isBefore(earliestPossibleTimeout)) {

final Instant oldTime = nextDataSample;

nextDataSample = nextTimeout(earliestPossibleTimeout);

log.warn("Next data sample was calculated to a time in the past '{}', resetting to a future time: {}", oldTime, nextDataSample);

}

Instant nextFtp = nextFtpConnection(currentTime, lastFtpConnection);

if (nextFtp.isBefore(earliestPossibleTimeout)) {

final Instant oldTime = nextFtp;

nextFtp = nextFtpConnection(earliestPossibleTimeout, lastFtpConnection);

log.warn("Next FTP connection was calculated to a time in the past '{}', resetting to a future time: {}", oldTime, nextFtp);

}

final boolean isFtpConnection = !nextDataSample.isBefore(nextFtp);

final boolean isDataSample = !isFtpConnection || nextDataSample.equals(nextFtp);

log.info("The next data sample at {} and the next FTP connection at {}", nextDataSample, nextFtp);

final Instant nextTimeout = nextDataSample.isBefore(nextFtp) ? nextDataSample : nextFtp;

final long millis = Duration.between(Instant.now(), nextTimeout).toMillis();

EXECUTORS.schedule(() -> {

log.info("Executing Webdyn service, isDataSample={}, isFtpConnection={}, nextTimeout={}, lastFtpConnection={}",

isDataSample, isFtpConnection, nextTimeout, lastFtpConnection);

long tme = System.nanoTime();

try {

connect(isDataSample, isFtpConnection, nextTimeout, lastFtpConnection);

log.warn("Completed webdyn service in {}s", (System.nanoTime() - tme) / 1000000);

} catch (final Throwable ex) {

log.error("Failed webdyn service after {}ms : {}", (System.nanoTime() - tme) / 1000000, ex.getMessage(), ex);

} finally {

scheduleNextTimeout(nextTimeout, isFtpConnection ? nextTimeout : lastFtpConnection);

}

}, millis, TimeUnit.MILLISECONDS);

log.warn("Completed webdyn schedule in {}ms, next execution at {} (in {} ms) will run as {}",

(System.nanoTime() - time) / 1000000, nextTimeout, millis, isFtpConnection ? "ftp-connection" : "data-sample");

} catch (final Throwable ex) {

log.error("Fatal error in webdyn schedule : {}", ex.getMessage(), ex);

}

}