Introduce Java Spring @component vs @service vs @repository
In the Spring Framework, @Component
, @Service
, and @Repository
are all annotations used to define Spring-managed beans, but they serve different purposes and convey different semantics. Here's a breakdown of each:
@Component
@Component
when you want to define a Spring bean that doesn't fit into the more specific categories of @Service
or @Repository
.import org.springframework.stereotype.Component;
@Component
public class MyComponent {
public void doSomething() {
// Implementation here
}
}
@Service
@Component
and is used to indicate that a class is a service. It typically contains business logic and is a layer in the service layer of an application.@Service
when you want to define a service layer bean that encapsulates business logic. It can also be used to indicate that the class is a service in the context of the application.import org.springframework.stereotype.Service;
@Service
public class MyService {
public void performService() {
// Business logic here
}
}
@Repository
@Component
and is used to indicate that a class is a Data Access Object (DAO). It is responsible for encapsulating the logic required to access data sources.@Repository
when you want to define a bean that interacts with the database or any other data source. It also provides additional features such as exception translation, which converts database-related exceptions into Spring's DataAccessException hierarchy.import org.springframework.stereotype.Repository;
@Repository
public class MyRepository {
public void saveData() {
// Data access logic here
}
}
Using these annotations appropriately helps in organizing your code and makes it clearer to other developers what the role of each class is within the application architecture.