run process in background using spring boot

Question

How can I run some process in background using Spring Boot? This is an example of what I need:

@SpringBootApplication
public class SpringMySqlApplication {

    @Autowired
    AppUsersRepo appRepo;

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

        while (true) {
            Date date = new Date();
            System.out.println(date.toString());
            try {
                TimeUnit.SECONDS.sleep(3);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
}

Answer 1

You can use Async behaviour. When you call the method and the current thread does wait for it to be finished.

Create a configurable class like this.

@Configuration
@EnableAsync
public class AsyncConfiguration {

    @Bean(name = "threadPoolTaskExecutor")
    public Executor threadPoolTaskExecutor() {
        return new ThreadPoolTaskExecutor();
    }
}

And then used in a method:

@Async("threadPoolTaskExecutor")
public void someAsyncMethod(...) {}

Have a look at spring documentation for more info

Answer 2

You could just use the @Scheduled-Annotation.

@Scheduled(fixedRate = 5000)
public void reportCurrentTime() {
     log.info("The time is now " + System.currentTimeMillis()));
}

https://spring.io/guides/gs/scheduling-tasks/:

The Scheduled annotation defines when a particular method runs. NOTE: This example uses fixedRate, which specifies the interval between method invocations measured from the start time of each invocation.