[英]Run multiple instances of the SAME cron job in Spring
I want to be able to run the SAME scheduled job in Spring. 我希望能够在Spring中运行SAME预定作业。 After searching on the Internet, I figured out how to run multiple different jobs at the same time.
在互联网上搜索后,我想出了如何同时运行多个不同的工作。
I have a @Service annotated class which has only one method, annotated with @Scheduled. 我有一个@Service注释类,它只有一个方法,用@Scheduled注释。 I want to have multiple instances of this job running at the same time.
我希望同时运行此作业的多个实例。
I am not using Quartz or Spring Batch( I have seen a lot of examples with Spring Batch). 我没有使用Quartz或Spring Batch(我已经看过很多Spring Batch的例子)。
The documentation doesn't clearly say if this can be achieved. 文档没有明确说明是否可以实现。
Yes, it can be easily achieved, but not with @Scheduled
annotation. 是的,它很容易实现,但不能使用
@Scheduled
注释。 How? 怎么样? Let me first explain how Spring works.
我先来解释一下Spring的工作原理。
Spring from every method annotated with @Scheduled
creates a new Runnable
object and then schedules it for execution to the TaskScheduler
( ThreadPoolTaskScheduler
to be precise). 每个使用
@Scheduled
注释的方法的Spring都会创建一个新的Runnable
对象,然后将其调度执行到TaskScheduler
(确切地说是ThreadPoolTaskScheduler
)。 To see the exact code look at ScheduledAnnotationBeanPostProcessor.processScheduled()
. 要查看确切的代码,请查看
ScheduledAnnotationBeanPostProcessor.processScheduled()
。
So to fulfill your requirement: have multiple instances of the same job, but without using Quartz or Spring Batch we need to abandon @Scheduled
annotation and do something a bit different than what the ScheduledAnnotationBeanPostProcessor
does by default. 因此,为了满足您的要求:拥有相同作业的多个实例,但是如果不使用Quartz或Spring Batch,我们需要放弃
@Scheduled
注释,并执行与ScheduledAnnotationBeanPostProcessor
默认情况相同的操作。
@Configuration
public class SpringConfig {
@Autowired
private TaskScheduler scheduler;
@Autowired
private YourServiceAnnotatedClass service;
@PostConstruct
public void startJobs() {
int numOfJobInstances = 3;
List<ImportantJob> jobs = IntStream.range(0, numOfJobInstances)
.mapToObj(i -> new ImportantJob("job" + i, service))
.collect(Collectors.toList());
jobs.forEach(this::schedule);
}
private void schedule(ImportantJob job) {
scheduler.schedule(job, new CronTrigger("*/5 * * * * *"));
// Above CronTrigger with 5 seconds was used, but feel free to use other variants, e.g.
// scheduler.scheduleAtFixedRate()
// scheduler.scheduleWithFixedDelay()
}
@Bean(destroyMethod = "shutdown")
public TaskScheduler taskScheduler() {
ThreadPoolTaskScheduler taskScheduler = new ThreadPoolTaskScheduler();
taskScheduler.setPoolSize(3); // Adjust it to your needs
return taskScheduler;
}
}
class ImportantJob implements Runnable {
private final String name;
private final YourServiceAnnotatedClass service;
public ImportantJob(String name, YourServiceAnnotatedClass service) {
this.name = name;
this.service = service;
}
@Override
public void run() {
service.doSth();
}
}
As you can see, although @Scheduled
is useful and simple, it is not very flexible. 正如您所看到的,尽管
@Scheduled
非常有用且简单,但它不是很灵活。 But with some effort you can gain much more control over scheduled tasks. 但通过一些努力,您可以更好地控制计划任务。
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