What's the difference between @Component, @Repository & @Service annotations in Spring

From Spring Documentation:

The @Repository annotation is a marker for any class that fulfils 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.

https://stackoverflow.com/questions/6827752/whats-the-difference-between-component-repository-service-annotations-in

以下是上述内容的中文翻译：

@Repository 注解是一个标记，用于任何符合仓库角色或存储库角色（也称为数据访问对象或 DAO）的类。此标记的用途之一是自动转换异常，如异常翻译中所述。

Spring 还提供了其他的Spring框架注解：@Component、@Service 和 @Controller。@Component 是一个通用的Spring框架注解，适用于任何由 Spring 管理的组件。@Repository、@Service 和 @Controller 是 @Component 的特化版本，用于更具体的使用场景（分别用于持久化层、服务层和表现层）。因此，你可以用 @Component 来注解你的组件类，但用 @Repository、@Service 或 @Controller 来注解这些类会更合适，因为这样更适合工具进行处理或与方面（aspects）关联。

例如，这些框架注解是为切入点设计的理想目标。@Repository、@Service 和 @Controller 在未来的 Spring Framework 版本中还可能包含更多语义。因此，如果在选择使用 @Component 或 @Service 来注解你的服务层时，@Service 显然是更好的选择。同样，如前所述，@Repository 已经被支持为持久化层中的自动异常翻译的标记。

参考链接：https://stackoverflow.com/questions/6827752/whats-the-difference-between-component-repository-service-annotations-in