The above annotations are closely related, so my questions are as follows:
1- Can @Component,
@Repository
and annotations @Service
be used interchangeably in Spring or do they provide any particular functionality besides acting as an annotation?
In other words, if I have a service class and I change the annotation from @Service
to @Component
:
2- Will it continue to behave in the same way? or does the annotation also influence the behavior and functionality of the class?
3-Could I exchange them and, for example, use @Service
when conceptually I should have @Repository
?
@Repository
and@Service
they are specializations of@Component
, adding a semantic value that indicates the usefulness of the annotated class (@Repository
for database access and@Service
for the business layer).Also, classes marked as
@Repository
are eligible to use a postprocessorPersistenceExceptionTranslationPostProcessor
, which translates DB errors into type exceptionsDataAccessException
(as per the class's javadoc)I understand that you will have no problem changing one annotation for another unless you use that postprocessor.
As the Spring documentation says , @Component is the main stereotype and indicates that a class with this annotation is a Spring component or Bean.
@Repository , @Service and @Controller are specifications of the @Component annotation for specific cases, for example, for data persistence, services or for the presentation layer respectively.
Therefore, you can annotate your beans with the @Component annotation , but annotating them with @Repository , @Service , or @Controller will give you additional benefits as some of the Spring modules handle these annotations differently.
You can generally use one instead of the other, but it is not recommended that you do so.