在自己的线程中运行每个Spring Scheduler [英] Running each Spring Scheduler in its own thread

问题描述

我有多个带有@Scheduled批注的组件，而且我发现即使一次调度它们同时运行，Spring一次也只能启动一个组件.

I have multiple components with @Scheduled annotations, and I see that Spring only starts one at a time, even if they are scheduled to run on the same time.

我的用例如下.我希望每个@Scheduled注释都可以在其自己的线程中运行，但每个线程只能运行一次.

My use case is as follows. I want each @Scheduled annotation to run in its own thread, but only once for each thread.

使用两个调度程序提供此伪代码:

Given this pseudo code with two schedulers:

@Scheduled(cron = "0 * * * * *") //run every minute
public void methodA() {
   log.info("Running method A");
   executeLongRunningJob("Finished method A");
}

@Scheduled(cron = "0 * * * * *") //run every minute
public void methodB() {
   log.info("Running method B");
   executeLongRunningJob("Finished method B");       
}

private void executeLongRunningJob(String msg) {
    Thread.sleep(70 seconds);
    System.out.println(msg);
}

请注意，该任务花费的时间比计划的调度程序要运行的时间更长.这很关键.我不希望调度程序在完成运行之前再次启动.

开箱即用地运行此代码将为我提供以下输出:

Running this code out of the box gives me this output:

Running method A
Finished method A
Running method B
Finished method B
Running method A
Finished method A
Running method B
Finished method B
... and so on

显然，它在单个线程中同时运行两个调度程序.

So obviously its running both schedulers in a single thread.

当我在昂贵的方法上放置@Async时，几乎可以得到正确的行为，除了昂贵的方法在启动新的调度程序之前尚未完成.

When I put @Async on my expensive method, then I almost get the correct behavior, except the expensive method is not finished before a new scheduler is started.

Running method A
Running method B
Running method A
Running method B
Finished method A
Finished method B
... and so on

---

我想要的是此输出:

---

What I would like is this output:

Running method A  
Running method B
Finished method A 
Finished method B 
Running method A 
Running method B 
Finished method A 
Finished method B
... and so on

我该怎么做? 我希望每个Scheduler能够同时运行，但是要等到它完成后才能再次运行. 请记住，我有两个以上的调度程序在相同的时间运行，有时甚至在不同的时间运行.

How can I accomplish this? I want each Scheduler to run concurrently, but wait until it is finished before allowed to run again. Remember I have more than two Schedulers running in same and sometimes different times.

推荐答案

您是对的-默认情况下，调度程序使用大小为1的线程池，因此将按顺序处理每个任务.您可以通过配置 TaskScheduler 具有所需池大小的bean.考虑以下示例:

You're right - by default scheduler uses a thread pool with size 1, so every task is being processed sequentially. You can it by configuring TaskScheduler bean with desired pool size. Consider following example:

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.scheduling.TaskScheduler;
import org.springframework.scheduling.annotation.EnableScheduling;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.scheduling.concurrent.ThreadPoolTaskScheduler;

import java.util.Date;

@SpringBootApplication
@EnableScheduling
public class Application {

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }

    @Bean
    public TaskScheduler taskScheduler() {
        final ThreadPoolTaskScheduler scheduler = new ThreadPoolTaskScheduler();
        scheduler.setPoolSize(10);
        return scheduler;
    }


    @Scheduled(fixedDelay = 2 * 1000L, initialDelay = 3 * 1000L)
    public void scheduled1() throws InterruptedException {
        System.out.println(new Date() + " " + Thread.currentThread().getName() + ": scheduled1");
        Thread.sleep(1000);
    }

    @Scheduled(fixedDelay = 3 * 1000L, initialDelay = 3 * 1000L)
    public void scheduled2() throws InterruptedException {
        System.out.println(new Date() + " " + Thread.currentThread().getName() + ": scheduled2");
        Thread.sleep(1000);
    }
}

它将在单独的线程中运行每个计划的任务，例如:

It will run every scheduled task in a separate thread, for example:

Tue Jul 18 20:21:50 CEST 2017 taskScheduler-1: scheduled2
Tue Jul 18 20:21:50 CEST 2017 taskScheduler-2: scheduled1
Tue Jul 18 20:21:53 CEST 2017 taskScheduler-1: scheduled1
Tue Jul 18 20:21:54 CEST 2017 taskScheduler-3: scheduled2
Tue Jul 18 20:21:56 CEST 2017 taskScheduler-2: scheduled1
Tue Jul 18 20:21:58 CEST 2017 taskScheduler-4: scheduled2
Tue Jul 18 20:21:59 CEST 2017 taskScheduler-1: scheduled1

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