Is Spring annotation Controller same as Service

Question

Is Spring annotation  Controller same as  Service   I have idea about  Controller which can be used for URL mapping and invoking business logic   while  Service used to annotate service class which contains business logic   Can I use  Controller instead of  Service to annotate Service class

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I already answered similar question on here Here is the Link

No both are different.

@Service annotation have use for other purpose and @Controller use for other. Actually Spring @Component, @Service, @Repository and @Controller annotations are used for automatic bean detection using classpath scan in Spring framework, but it doesn't ,mean that all functionalities are same. @Service: It indicates annotated class is a Service component in the business layer.

@Controller: Annotated class indicates that it is a controller components, and mainly used at presentation layer.

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No  they are pretty different from each other   Both are different specializations of  Component annotation  in practice  they re two different implementations of the same interface  so both can be discovered by the classpath scanning  if you declare it in your XML configuration    Service annotation is used in your service layer and annotates classes that perform service tasks  often you don t use it but in many case you use this annotation to represent a best practice  For example  you could directly call a DAO class to persist an object to your database but this is horrible  It is pretty good to call a service class that calls a DAO  This is a good thing to perform the separation of concerns pattern    Controller annotation is an annotation used in Spring MVC framework  the component of Spring Framework used to implement Web Application   The  Controller annotation indicates that a particular class serves the role of a controller  The  Controller annotation acts as a stereotype for the annotated class  indicating its role  The dispatcher scans such annotated classes for mapped methods and detects  RequestMapping annotations   So looking at the Spring MVC architecture you have a DispatcherServlet class  that you declare in your XML configuration  that represent a front controller that dispatch all the HTTP Request towards the appropriate controller classes  annotated by  Controller   This class perform the business logic  and can call the services  by its method  These classes  or its methods  are typically annotated also with  RequestMapping annotation that specify what HTTP Request is handled by the controller and by its method   For example    Controller  RequestMapping   appointments   public class AppointmentsController        private final AppointmentBook appointmentBook        Autowired     public AppointmentsController AppointmentBook appointmentBook            this appointmentBook   appointmentBook              RequestMapping method   RequestMethod GET      public Map lt String  Appointment gt  get             return appointmentBook getAppointmentsForToday            This class is a controller   This class handles all the HTTP Request toward   appointments   folder  and in particular the get method is the method called to handle all the GET HTTP Request toward the folder   appointments    I hope that now it is more clear for you

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If you look at the definitions of  Controller   Service annotations  then you ll find that these are special type of  Component annotation    Component public  interface Service                     Component public  interface Controller                 So what s the difference       Controller   The  Controller annotation indicates that a particular class serves the role of a controller  The  Controller annotation acts as a stereotype for the annotated class  indicating its role   What   s special about  Controller     You cannot switch this annotation with any other like  Service or  Repository  even though they look same   The dispatcher scans the classes annotated with  Controller and detects  RequestMapping annotations within them  You can only use  RequestMapping on  Controller annotated classes         Service    Services hold business logic and call method in repository layer    What   s special about  Service     Apart from the fact that it is used to indicate that it s holding the business logic  there   s no noticeable specialty that this annotation provides  but who knows  spring may add some additional exceptional in future   Linked answer  What s the difference between  Component   Repository  amp   Service annotations in Spring

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Service vs  Controller    Service   class is a  Business Service Facade   in the Core J2EE patterns sense   or something similar    Controller   Indicates that an annotated class is a  Controller   e g  a web controller    ----------Find Usefull notes on Major Stereotypes http   docs spring io spring docs current javadoc-api org springframework stereotype Component html   interface Component     Target value TYPE        Retention value RUNTIME        Documented     public  interface Component   Indicates that an annotated class is a component  Such classes are considered as candidates for auto-detection when using annotation-based configuration and classpath scanning    Other class-level annotations may be considered as identifying a component as well  typically a special kind of component  e g  the  Repository annotation or AspectJ s  Aspect annotation    interface Controller   Target value TYPE    Retention value RUNTIME    Documented   Component public  interface Controller   Indicates that an annotated class is a  Controller   e g  a web controller    This annotation serves as a specialization of  Component  allowing for implementation classes to be autodetected through classpath scanning  It is typically used in combination with annotated handler methods based on the RequestMapping annotation    interface Service   Target value TYPE    Retention value RUNTIME    Documented   Component public  interface Service   Indicates that an annotated class is a  Service   originally defined by Domain-Driven Design  Evans  2003  as  an operation offered as an interface that stands alone in the model  with no encapsulated state   May also indicate that a class is a  Business Service Facade   in the Core J2EE patterns sense   or something similar  This annotation is a general-purpose stereotype and individual teams may narrow their semantics and use as appropriate   This annotation serves as a specialization of  Component  allowing for implementation classes to be autodetected through classpath scanning    interface Repository   Target value TYPE    Retention value RUNTIME    Documented   Component public  interface Repository   Indicates that an annotated class is a  Repository   originally defined by Domain-Driven Design  Evans  2003  as  a mechanism for encapsulating storage  retrieval  and search behavior which emulates a collection of objects   Teams implementing traditional J2EE patterns such as  Data Access Object  may also apply this stereotype to DAO classes  though care should be taken to understand the distinction between Data Access Object and DDD-style repositories before doing so  This annotation is a general-purpose stereotype and individual teams may narrow their semantics and use as appropriate   A class thus annotated is eligible for Spring DataAccessException translation when used in conjunction with a PersistenceExceptionTranslationPostProcessor  The annotated class is also clarified as to its role in the overall application architecture for the purpose of tooling  aspects  etc   As of Spring 2 5  this annotation also serves as a specialization of  Component  allowing for implementation classes to be autodetected through classpath scanning

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No   Controller is not the same as  Service  although they both are specializations of  Component  making them both candidates for discovery by classpath scanning  The  Service annotation is used in your service layer  and  Controller is for Spring MVC controllers in your presentation layer  A  Controller typically would have a URL mapping and be triggered by a web request

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From Spring In Action  As you can see  this class is annotated with  Controller  On its own   Controller doesn   t do much  Its primary purpose is to identify this class as a component for component scanning  Because HomeController is annotated with  Controller  Spring   s component scanning automatically discovers it and creates an instance of HomeController as a bean in the Spring application context  In fact  a handful of other annotations  including  Component   Service  and  Repository  serve a purpose similar to  Controller  You could have just as effectively annotated HomeController with any of those other annotations  and it would have still worked the same  The choice of  Controller is  however  more descriptive of this component   s role in the application

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No you can t they are different  When the app was deployed your controller mappings would be borked for example   Why do you want to anyway  a controller is not a service  and vice versa

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You can declare a  service as  Controller   You can NOT declare an  Controller as  Service   Service  It is regular  You are just declaring class as a Component    Controller  It is a little more special than Component  The dispatcher will search for  RequestMapping here   So a class annotated with  Controller  will be additionally empowered with declaring URLs through which APIs are called

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Controller will handle the navigation between the different views  Your mappings request mappings are handled with the help of controller  Service interacts directly with the repository where usually the business logic is performed  You can add  delete  remove etc at the service layer

[spring] Is Spring annotation @Controller same as @Service?

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