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martinezhenry
martinezhenry

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Spring Boot Async

#beginners #programming #springboot

Today we talk about how to use the annotation @Async of Spring Boot to create method asynchronous in our applications.

Using asynchronous methods allows you to execute tasks that require much time to finish without waiting.

Environment

  • Java 11
  • Spring Boot 7.0.1
  • Maven 3.8.6

Preparing a Method

In this example, we used a method called processDelay that executes a random delay time from 0 to 1500 milliseconds. This method looks like this:

public void processDelay() throws InterruptedException {
      long delay = ThreadLocalRandom.current().nextLong(0, 1500 + 1);
      log.info("processing delay: {}", delay);
      Thread.sleep(delay);
      log.info("delay time processed");

}
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The sentence Thread.sleep(delay); is the apply the delay time and the sentence long delay = ThreadLocalRandom.current().nextLong(0, 1500 + 1); get a random long number from 0 to 1500 to indicate the first one the time to wait.

Using @Async

With this annotation we can convert a simple method into an asynchronous method, in our example we will convert processDelay method to an asynchronous one, we only need to add the annotation @Async at the top of our method, like this:

@Async
public void processDelay() throws InterruptedException {
    long delay = ThreadLocalRandom.current().nextLong(0, 1500 + 1);
    log.info("processing delay: {}", delay);
    Thread.sleep(delay);
    log.info("delay time processed");
}
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Enabling Async

To can use @Async annotation also we need to active the Spring Boot features async, for do that, we need to add the annotation @EnableAsync, this one should be added to a class, I prefer to include it on the main class.

Example:

@SpringBootApplication
@EnableAsync
public class AsyncApplication {
    public static void main(String[] args) {
        SpringApplication.run(AsyncApplication.class, args);
    }
}
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Testing

To validate the async method we will use a @RestController to call our method and pass it how many executions to apply the method, this is our controller example:

@RestController
@Slf4j
public class DelayController implements IDelayController {

    private final IAsyncProcessorService asyncProcessorService;

    public DelayController(IAsyncProcessorService asyncProcessorService){
        this.asyncProcessorService = asyncProcessorService;
    }

    @Override
    @GetMapping(value = "delay/{executions}")
    public void processDelayTime(@PathVariable(value = "executions") int executions) throws InterruptedException {
        log.info("Tries: {}", executions);
        for(int i = 0; i < executions; i++) {
            this.asyncProcessorService.processDelay();
        }
    }
}
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now, if we run the application and request our controller, we can see how the method is executed as a background task.

022-11-07 22:14:08.958  INFO 35748 --- [nio-8080-exec-2] c.h.l.c.implementations.DelayController  : Tries: 2
2022-11-07 22:14:08.968  INFO 35748 --- [         task-2] c.h.l.s.i.AsyncProcessorService          : processing delay: 957
2022-11-07 22:14:08.968  INFO 35748 --- [         task-1] c.h.l.s.i.AsyncProcessorService          : processing delay: 263
2022-11-07 22:14:09.249  INFO 35748 --- [         task-1] c.h.l.s.i.AsyncProcessorService          : delay time processed
2022-11-07 22:14:09.926  INFO 35748 --- [         task-2] c.h.l.s.i.AsyncProcessorService          : delay time processed
2022-11-07 22:14:15.184  INFO 35748 --- [nio-8080-exec-3] c.h.l.c.implementations.DelayController  : Tries: 2
2022-11-07 22:14:15.185  INFO 35748 --- [         task-3] c.h.l.s.i.AsyncProcessorService          : processing delay: 403
2022-11-07 22:14:15.185  INFO 35748 --- [         task-4] c.h.l.s.i.AsyncProcessorService          : processing delay: 736
2022-11-07 22:14:15.591  INFO 35748 --- [         task-3] c.h.l.s.i.AsyncProcessorService          : delay time processed
2022-11-07 22:14:15.924  INFO 35748 --- [         task-4] c.h.l.s.i.AsyncProcessorService          : delay time processed
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The response is very fast, indicating that the controller is not waiting for the delay, other evidence that the method is executing asynchronously.

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Conclusion

In this post, we can see how to use the Spring Boot @Async annotation to execute methods in background tasks without that we need to wait until the execution finishes.

References

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