@Component、@Repository & 之间有什么区别?Spring 中的 @Service 注释? [英] What's the difference between @Component, @Repository & @Service annotations in Spring?

问题描述

可以@Component, @Repository 和 @Service 注释在 Spring 中可以互换使用，还是除了充当注释设备之外还提供任何特定功能?

Can @Component, @Repository and @Service annotations be used interchangeably in Spring or do they provide any particular functionality besides acting as a notation device?

换句话说，如果我有一个 Service 类并且我将注释从 @Service 更改为 @Component，它的行为是否仍然相同?

In other words, if I have a Service class and I change the annotation from @Service to @Component, will it still behave the same way?

或者注解是否也会影响类的行为和功能?

Or does the annotation also influence the behavior and functionality of the class?

推荐答案

来自 Spring 文档:

@Repository 注释是任何满足存储库的角色或构造型(也称为数据访问对象或 DAO).此标记的用途之一是自动翻译异常，如 异常翻译.

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 提供了更多的构造型注解:@Component、@Service、和 @Controller.@Component 是任何的通用构造型Spring 管理的组件.@Repository、@Service 和 @Controller 是@Component 的专门化，用于更具体的用例(在分别为持久层、服务层和表示层).因此，您可以使用 @Component 注释您的组件类，但是，通过使用 @Repository、@Service 或 @Controller 注释它们相反，您的类更适合由工具处理或与方面相关联.

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.

比如这些构造型注释为切入点制作理想的目标.@Repository、@Service 和@Controller 还可以在未来的版本中携带额外的语义弹簧框架.因此，如果您在使用之间进行选择@Component 或 @Service 用于您的服务层，@Service 显然是更好的选择.同样，如前所述，@Repository 已经是支持作为自动异常翻译的标记持久层.

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.

<头>

注释	含义
@Component	任何 Spring 管理组件的通用构造型
@Repository	持久层的原型
@Service	服务层的原型
@Controller	表示层的原型(spring-mvc)

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