어노테이션 @PostConstruct, @PreDestroy

@PostConstruct, @PreDestroy 어노테이션 사용시 가장 편리하게 초기화와 종료 실행 가능

- src/test/java/hello/core/lifecycle/NetworkClient.java

...
import jakarta.annotation.PostConstruct;
import jakarta.annotation.PreDestroy;
...
    @PostConstruct
    public void init() {
        System.out.println("NetworkClient.init");
        connect();
        call("초기화 연결 메시지");
    }

    @PreDestroy
    public void close() {
        System.out.println("NetworkClient.close");
        disConnect();
    }
...

- src/test/java/hello/core/lifecycle/BeanLifeCycleTest.java

...
    @Configuration
    static class LifeCycleConfig {

        // @Bean(initMethod = "init", destroyMethod = "close")
        @Bean
        public NetworkClient networkClient() {
            NetworkClient networkClient = new NetworkClient();
            networkClient.setUrl("http://hello-spring.dev");
            return networkClient;
        }

    }
...

- 콘솔

생성자 호출, url = null
NetworkClient.init
connect: http://hello-spring.dev
call: http://hello-spring.dev, message = 초기화 연결 메시지
23:26:19.005 [Test worker] DEBUG o.s.c.a.AnnotationConfigApplicationContext --Closing org.springframework.context.annotation.AnnotationConfigApplicationContext@3241713e, started on Mon May 04 23:26:18 KST 2026
NetworkClient.close
close: http://hello-spring.dev

1) @PostConstruct, @PreDestroy 특징
· 최신 스프링에서 가장 권장하는 방법으로, 어노테이션 하나만 붙이면 되니 매우 편리하다.
· 패키지가 javax.annotation.PostConstruct 이므로, 스프링 종속적인 기술이 아닌 JSR-250 이라는 자바 표준이다.
따라서 스프링이 아닌 다른 컨테이너에서도 동작한다.
· 컴포넌트 스캔과 잘 어울린다.
· 유일한 단점은 외부 라이브러리에는 적용하지 못한다.
외부 라이브러리 초기화, 종료시 @Bean 기능을 사용한다.


2) 정리
@PostConstruct, @PreDestroy 어노테이션 사용
코드를 고칠 수 없는 외부 라이브러리 초기화, 종료시 @Bean 의 initMethod, destroyMethod 사용


참고링크 : https://www.inflearn.com/course/%EC%8A%A4%ED%94%84%EB%A7%81-%ED%95%B5%EC%8B%AC-%EC%9B%90%EB%A6%AC-%EA%B8%B0%EB%B3%B8%ED%8E%B8?cid=325969

스프링 핵심 원리 - 기본편| 김영한 - 인프런 강의