我可以在@Scheduled 中添加上下文吗？

Question

这是我的代码：

 @Scheduled(cron = "30 3 * * * *")
    public void myCron() {
        //we don't care what we do here
    }

我想知道是否可以在我的@Scheduled自动添加跟踪 ID（或其他信息）。

每次@Scheduled触发时 id 都会不同。

我想这样做是为了避免重复代码，例如：

@Scheduled(cron = "10 3 * * * *")
public void myCron() {
    MDC.put("myId", UUID.randomUUID().toString());
    //we don't care what we do here
}
@Scheduled(cron = "30 3 * * * *")
public void mySecondCron() {
    MDC.put("myId", UUID.randomUUID().toString());
    //we don't care what we do here
}

我厌倦了实现SchedulingConfigurer但是SchedulingConfigurer#configureTasks太晚了，因为任务（可运行）已经创建了

谢谢

Answer 1

您可以尝试实现自定义TaskScheduler并在SchedulingConfigurer.configureTasks. ConcurrentTaskScheduler可以视为一个例子。不幸的是，这个类不是为继承而精心设计的，否则decorateTask方法将受到保护。因此，您需要覆盖所有方法以使用您的逻辑添加一个额外的 Runnable 装饰器。像这样的东西：

@Configuration
@EnableScheduling
public class ScheduledConfig implements SchedulingConfigurer {

    public static class MyTaskScheduler extends ConcurrentTaskScheduler {

        public MyTaskScheduler() {
        }

        public MyTaskScheduler(ScheduledExecutorService scheduledExecutor) {
            super(scheduledExecutor);
        }

        public MyTaskScheduler(Executor concurrentExecutor, ScheduledExecutorService scheduledExecutor) {
            super(concurrentExecutor, scheduledExecutor);
        }

        // TODO override other methods

        @Override
        public ScheduledFuture<?> schedule(Runnable task, Trigger trigger) {
            return super.schedule(decorateTask(task), trigger);
        }

        private Runnable decorateTask(Runnable task) {
            // not 100% sure about safety of this cast
            return new MyRunnable((ScheduledMethodRunnable) task);
        }

        private static class MyRunnable implements Runnable {

            private final ScheduledMethodRunnable runnable;
            private final AtomicLong counter = new AtomicLong();

            public MyRunnable(ScheduledMethodRunnable runnable) {
                this.runnable = runnable;
            }

            @Override
            public void run() {
                System.out.println(runnable.getMethod().toGenericString() + " " + counter.incrementAndGet());
                runnable.run();
            }
        }
    }

    @Override
    public void configureTasks(ScheduledTaskRegistrar taskRegistrar) {
        TaskScheduler taskScheduler = new MyTaskScheduler(Executors.newScheduledThreadPool(10));
        taskRegistrar.setTaskScheduler(taskScheduler);
    }

    @Scheduled(cron = "0/1 * * * * *")
    public void test() {
        System.out.println("Running task in thread " + Thread.currentThread().getId());
    }
}