java - spring-boot @scheduled 没有在不同的线程中运行？

Question

我正在配置计划任务以在不同线程中运行。下面是配置代码

@Configuration
@EnableScheduling
public class SchedulerConfig implements SchedulingConfigurer {
    private final int POOL_SIZE = 10;

    @Override
    public void configureTasks(ScheduledTaskRegistrar scheduledTaskRegistrar) {
        ThreadPoolTaskScheduler threadPoolTaskScheduler = new ThreadPoolTaskScheduler();
        threadPoolTaskScheduler.setPoolSize(POOL_SIZE);
        threadPoolTaskScheduler.setThreadNamePrefix("my-sched-pool-");
        threadPoolTaskScheduler.initialize();
        scheduledTaskRegistrar.setTaskScheduler(threadPoolTaskScheduler);
    }
}

这是使用它的代码

@Scheduled(fixedRateString = "2000" )
    public void testaMethod() {

         log.debug("here is the message");
        try {
            Thread.sleep(10000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

    }

我正在让线程 hibernate 10 秒，固定速率为 2 秒。所以我希望在日志中看到不同的线程但我只看到一个

日志在这里

{"thread":"my-sched-pool-1","level":"DEBUG","description":"here is the message"}
{"thread":"my-sched-pool-1","level":"DEBUG","description":"here is the message"}
{"thread":"my-sched-pool-1","level":"DEBUG","description":"here is the message"}
{"thread":"my-sched-pool-1","level":"DEBUG","description":"here is the message"}

Answer 1

@Scheduled(fixedRateString = "2000")不保证testaMethod每2秒执行一次，如果时间成本超过2s，比如 Thread.sleep(10000)，新任务会被放入一个队列中。只有当旧任务执行完毕后，调度程序才会从队列中取出新任务并执行它。由于新任务现在是调度程序中的唯一任务，因此无需创建新的 Thread 即可运行它。

要解决这个问题，你可以组合@Async and @Scheduled

调度器配置

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.scheduling.TaskScheduler;
import org.springframework.scheduling.annotation.EnableScheduling;
import org.springframework.scheduling.annotation.SchedulingConfigurer;
import org.springframework.scheduling.concurrent.ThreadPoolTaskScheduler;
import org.springframework.scheduling.config.ScheduledTaskRegistrar;

@Configuration
@EnableScheduling
public class SchedulerConfig implements SchedulingConfigurer {
    private final int POOL_SIZE = 10;

    @Override
    public void configureTasks(ScheduledTaskRegistrar scheduledTaskRegistrar) {
        scheduledTaskRegistrar.setTaskScheduler(poolScheduler());
    }

    @Bean
    public TaskScheduler poolScheduler() {
        ThreadPoolTaskScheduler scheduler = new ThreadPoolTaskScheduler();
        scheduler.setThreadNamePrefix("poolScheduler");
        scheduler.setPoolSize(POOL_SIZE);
        return scheduler;
    }

}

调度任务

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Component;

@Component
public class SchedulerTask {

    @Autowired
    private AsyncTask asyncTask;

    @Scheduled(fixedRateString = "2000" )
    public void testaMethod() {
        asyncTask.asyncMethod();
    }
}

异步任务

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.scheduling.annotation.Async;
import org.springframework.scheduling.annotation.EnableAsync;
import org.springframework.stereotype.Component;

@Component
@EnableAsync
public class AsyncTask {

    private Log log = LogFactory.getLog(AsyncTask.class);

    @Async
    public void asyncMethod() {
        log.debug("here is the message");
        try {
            Thread.sleep(10000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}

测试结果

11:20:54.682 [poolScheduler1] DEBUG com.test.AsyncTask - here is the message
11:20:56.668 [poolScheduler3] DEBUG com.test.AsyncTask - here is the message
11:20:58.668 [poolScheduler2] DEBUG com.test.AsyncTask - here is the message
11:21:00.669 [poolScheduler6] DEBUG com.test.AsyncTask - here is the message
11:21:02.669 [poolScheduler7] DEBUG com.test.AsyncTask - here is the message
11:21:04.669 [poolScheduler4] DEBUG com.test.AsyncTask - here is the message