Call a method after Spring Boot app starts

Question

I have a Java Spring Boot application which has a Scheduler which calls a async task from a Service The task takes a few minutes (usually 3-5mins) to complete.

The same async method from the Service can also be called trough a UI Application, by calling the API from the Spring Boot Controller.

Code:

Scheduler

@Component
public class ScheduledTasks {
  @Autowired
  private MyService myService;

  @Scheduled(cron = "0 0 */1 * * ?")
  public void scheduleAsyncTask() {
    myService.doAsync();
  }
}

Service

@Service
public class MyService {
  @Async("threadTaskExecutor")
  public void doAsync() {
    //Do Stuff
  }
}

Controller

@CrossOrigin
@RestController
@RequestMapping("/mysrv")
public class MyController {
  @Autowired
  private MyService myService;

  @CrossOrigin
  @RequestMapping(value = "/", method = RequestMethod.POST)
  public void postAsyncUpdate() {
    myService.doAsync();
  }
}

The scheduler runs the async task every hour, but a user can also run it manually from the UI.

But, I do not want the async method to run again if it is already in the middle of execution.

In order to do that, I have created a table in DB which contains a flag which goes on when the method is running and then it is turned off after the method completes.

Something like this in my service class:

@Autowired
private MyDbRepo myDbRepo;

@Async("threadTaskExecutor")
public void doAsync() {
  if (!myDbRepo.isRunning()) {
    myDbRepo.setIsRunning(true);
    //Do Stuff
    myDbRepo.setIsRunning(false);
  } else {
    LOG.info("The Async task is already running");
  }
}

Now, the problem is that the flag sometimes gets stuck due to various reasons (app restarting, some other application error etc.)

So, I want to reset the flag in DB each time the spring boot application is deployed and whenever is restarts.

How can I do that? Is there some way to run a method just after the Spring Boot Application starts, from where I can call a method from my Repo to un set the flags in the database?

Answer 1

Check for the @PostConstruct for e.g here https://www.baeldung.com/running-setup-logic-on-startup-in-spring

Answer 2

If you want to do some stuff after whole application booted and ready use below sample from

import org.springframework.boot.context.event.ApplicationReadyEvent;
import org.springframework.context.ApplicationListener;
import org.springframework.stereotype.Component;

@Component
public class ApplicationStartup 
implements ApplicationListener<ApplicationReadyEvent> {

  /**
   * This event is executed as late as conceivably possible to indicate that 
   * the application is ready to service requests.
   */
  @Override
  public void onApplicationEvent(final ApplicationReadyEvent event) {

    // here your code ...

    return;
  }

} // class

If it is enough to hook after a single bean creating use @PostConstruct as suggested by @loan M