Quick Answer: What Is The Difference Between @Component And @Controller?

What is difference between @component and @configuration?

@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.

A @Configuration is also a @Component, but a @Component cannot act like a @Configuration..

What’s the difference between @component @repository & @service annotations in spring?

Differences in NutShell: Both @Service and @Repository annotations are the specializations over the @Component annotation. @Repository is a stereotype used for persistence layer. It translates any persistence related exceptions into a Spring’s DataAccessException. @Service is used for the beans at the service layer.

What is the use of @configuration in spring?

Spring @Configuration annotation is part of the spring core framework. Spring Configuration annotation indicates that the class has @Bean definition methods. So Spring container can process the class and generate Spring Beans to be used in the application.

What is @ComponentScan?

The @ComponentScan annotation is used with the @Configuration annotation to tell Spring the packages to scan for annotated components. … The @ComponentScan annotation uses the basePackages attribute to specify three packages (and subpackages) that will be scanned by Spring.

What is the use of @RequestMapping?

@RequestMapping is one of the most widely used Spring MVC annotation. … RequestMapping annotation is used to map web requests onto specific handler classes and/or handler methods. @RequestMapping can be applied to the controller class as well as methods.

What is difference between @component and @bean in spring?

@Component auto detects and configures the beans using classpath scanning whereas @Bean explicitly declares a single bean, rather than letting Spring do it automatically.

What is the use of @bean annotation in spring?

@Bean annotation indicates that the annotated method produces a bean to be managed by the Spring container. It is a direct analog of the XML tag. @Bean supports most of the attributes offered by , such as: init-method , destroy-method , autowiring , lazy-init , dependency-check , depends-on , scope .

What @RestController will do?

Spring RestController annotation is used to create RESTful web services using Spring MVC. Spring RestController takes care of mapping request data to the defined request handler method. Once response body is generated from the handler method, it converts it to JSON or XML response.

What is @RequestMapping?

@RequestMapping is one of the most common annotation used in Spring Web applications. This annotation maps HTTP requests to handler methods of MVC and REST controllers. In this post, you’ll see how versatile the @RequestMapping annotation is when used to map Spring MVC controller methods.

What is @controller in spring boot?

@Controller annotation indicates that the annotated class is a controller. It is a specialization of @Component and is autodetected through classpath scanning. It is typically used in combination with annotated handler methods based on the @RequestMapping annotation.

Can we replace @service with @component?

2 Answers. According to documentaion @Repository , @Service , @Controller are all synonyms. They all just specializations of @Component annotation. So, generally, they can be used one istead of other.

What is spring bean life cycle?

Advertisements. The life cycle of a Spring bean is easy to understand. When a bean is instantiated, it may be required to perform some initialization to get it into a usable state. Similarly, when the bean is no longer required and is removed from the container, some cleanup may be required.

What is value in @RequestMapping?

As mentioned in the comments (and the documentation), value is an alias to path . Spring often declares the value element as an alias to a commonly used element. In the case of @RequestMapping (and @GetMapping , …) this is the path property: This is an alias for path() .

Can we use @component instead of @controller?

2 Answers. @Controller is a @Component (just like @Service , @Repository , @Endpoint etc.). The @Component is used as a meta-annotation here so that it can be picked-up using component-scanning. Next to that the @Controller is a special component which will have some added functionality (Spring MVC takes care of that).

Is @component a singleton?

Yes, that is correct, @Component is a Spring bean and a Singleton. About singletons – spring beans are all in singleton scope by default.

Can we use @component instead of @repository?

The difference between them is, @component is used to annotate compound classes, @Repository is a marker for automatic exception translation in the persistence layer, for service layer we need to use @service. You can refer Spring Documentation to know more.

What is use of @autowired in spring?

The @Autowired annotation can be used to autowire bean on the setter method just like @Required annotation, constructor, a property or methods with arbitrary names and/or multiple arguments. …

What is the use of @component?

@Component is the most generic Spring annotation. A Java class decorated with @Component is found during classpath scanning and registered in the context as a Spring bean. @Service , @Repository , and @Controller are specializations of @Component , which are used for more specific cases.