Async
- separate the thread
- response time (when processing an event - exception 이 발생해도 콜러에 영향을 주지 않음)
ApplicationEventPublisher
publishEvent(Object event)Notify all matching listeners registered with this application of an event.
Publishing an Event
public class StudyService {
private final StudyRepository studyRepository;
private final ModelMapper modelMapper;
private final ApplicationEventPublisher eventPublisher;
public Study createNewStudy(Study study, Account account) {
Study newStudy = studyRepository.save(study);
newStudy.addManager(account);
eventPublisher.publishEvent(new StudyCreatedEvent(newStudy));
return newStudy;
}
}Event
- object or ApplicationEvent type https://docs.spring.io/spring-framework/docs/current/javadoc-api/org/springframework/context/ApplicationEvent.html
@Getter
public class StudyCreatedEvent {
private Study study;
public StudyCreatedEvent(Study study) {
this.study = study;
}
}Listener
- ApplicationListener를 구현하는 대신 @EventListener annotation 추가
- 비동기 → exception 이 발생해도 콜러에 영향을 주지 않음
@Async
@Slf4j
@Transactional(readOnly = true)
@Component
public class StudyEventListener {
@EventListener
public void handleStudyCreatedEvent(StudyCreatedEvent studyCreatedEvent) {
Study study = studyCreatedEvent.getStudy();
log.info(study.getTitle() + " is created.");
// TODO 해당 스터디 주제에 관심이 있는 사용자에게 알림
}
}