[JAVA] 헷갈려서 적는 @Component, @Repository, @Service, @Controller

참고 : http://namocom.tistory.com/421

1.10.1. @Component and Further Stereotype Annotations

The @Repository annotation is a marker for any class that fulfills the role or stereotype of a repository (also known as Data Access Object or DAO). Among the uses of this marker is the automatic translation of exceptions, as described in Exception Translation.

Spring provides further stereotype annotations: @Component, @Service, and @Controller. @Component is a generic stereotype for any Spring-managed component. @Repository, @Service, and @Controller are specializations of @Component for more specific use cases (in the persistence, service, and presentation layers, respectively). Therefore, you can annotate your component classes with @Component, but, by annotating them with @Repository, @Service, or @Controller instead, your classes are more properly suited for processing by tools or associating with aspects. For example, these stereotype annotations make ideal targets for pointcuts. @Repository, @Service, and @Controller can also carry additional semantics in future releases of the Spring Framework. Thus, if you are choosing between using @Component or @Service for your service layer, @Service is clearly the better choice. Similarly, as stated earlier, @Repository is already supported as a marker for automatic exception translation in your persistence layer.

어노테이션	유스케이스
@Repository	퍼시스턴스(persistence) 레이어, 영속성을 가지는 속성(파일, 데이터베이스 등)
@Service	서비스 레이어
@Controller	프레젠테이션 레이어

component 의 구체화 -> Service 

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https://okky.kr/article/367591

WEB(사용자) ==요청==> Controller ==요청==> Service (내부적인 처리) ==리턴값==> Controller