Can we interchange @Controller and @Service in spring?

Question

Can we interchange @Controller and @Service in spring? I tried and it was working. How are they implemented internally?

Answer 1

@Controller and @Service are special form of @Component. Spring allows you to use it interchangeably, but is it NOT recommended to do it that way. As for instance the @Controller is used on classes to that serves are the Controller on the MVC. Also, spring dispatcher servlet will scan for @RequestMapping on classes which are annotated using @Controller.

Answer 2

@Component
    ------@Controller
    ------@Service
    ------@Repository

@Controller and @Service are ultimately part of @Component. You may interchange them but it is not recommended or follow best practices. The purpose of using 3 different annotation is to we can have separate the layers based on it use more appropriate annotation.

@Controller:

• Annotated class indicates that it is a controller component, and mainly used at the presentation layer.

• @Controller is used to mark classes as Spring MVC Controller. This annotation is just a specialized version of @Component and it allows the controller classes to be auto-detected based on classpath scanning.

@Service: It indicates annotated class is a Service component in the business layer.