@Transactional on @PostConstruct method

Question

I want to read text data fixtures (CSV files) at the start on my application and put it in my database.

For that, I have created a PopulationService with an initialization method (@PostConstruct annotation).

I also want them to be executed in a single transaction, and hence I added @Transactional on the same method.

However, the @Transactional seems to be ignored : The transaction is started / stopped at my low level DAO methods.

Do I need to manage the transaction manually then ?

Answer 1

Quote from legacy (closed) Spring forum:

In the @PostConstruct (as with the afterPropertiesSet from the InitializingBean interface) there is no way to ensure that all the post processing is already done, so (indeed) there can be no Transactions. The only way to ensure that that is working is by using a TransactionTemplate.

So if you would like something in your @PostConstruct to be executed within transaction you have to do something like this:

@Service("something")
public class Something {
    
    @Autowired
    @Qualifier("transactionManager")
    protected PlatformTransactionManager txManager;

    @PostConstruct
    private void init(){
        TransactionTemplate tmpl = new TransactionTemplate(txManager);
        tmpl.execute(new TransactionCallbackWithoutResult() {
            @Override
            protected void doInTransactionWithoutResult(TransactionStatus status) {
                //PUT YOUR CALL TO SERVICE HERE
            }
        });
   }
}

Answer 2

I think @PostConstruct only ensures the preprocessing/injection of your current class is finished. It does not mean that the initialization of the whole application context is finished.

However you can use the spring event system to receive an event when the initialization of the application context is finished:

public class MyApplicationListener implements ApplicationListener<ContextRefreshedEvent> {
  public void onApplicationEvent(ContextRefreshedEvent event) {
    // do startup code ..
  }    
}

See the documentation section Standard and Custom Events for more details.

Answer 3

As an update, from Spring 4.2 the @EventListener annotation allows a cleaner implementation:

@Service
public class InitService {

    @Autowired
    MyDAO myDAO;

    @EventListener(ContextRefreshedEvent.class)
        public void onApplicationEvent(ContextRefreshedEvent event) {
        event.getApplicationContext().getBean(InitService.class).initialize();
    }

    @Transactional
    public void initialize() {
        // use the DAO
    }

}