Question: What’S The Difference Between @Controller And @RestController?

Why do we use @RestController?

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 the difference between @controller and @component?

@Component : It is a basic auto component scan annotation, it indicates annotated class is an auto scan component. @Controller : Annotated class indicates that it is a controller component, and mainly used at the presentation layer. @Service : It indicates annotated class is a Service component in the business layer.

What is the @controller annotation used for?

The basic purpose of the @Controller annotation is to act as a stereotype for the annotated class, indicating its role. The dispatcher will scan such annotated classes for mapped methods, detecting @RequestMapping annotations (see the next section).

Where is REST API used?

One of the most popular types of API is REST or, as they’re sometimes known, RESTful APIs. REST or RESTful APIs were designed to take advantage of existing protocols. While REST – or Representational State Transfer – can be used over nearly any protocol, when used for web APIs it typically takes advantage of HTTP.

What is REST API example?

An application implementing a RESTful API will define one or more URL endpoints with a domain, port, path, and/or querystring — for example, https://mydomain/user/123?format=json .

Why Spring controller is Singleton?

By default, Spring beans are singletons. Spring suggests to use singletons for stateless beans like controllers and DAOs, and prototype scope for stateful beans. The Struts2 Actions are not singletons because they carry state. … The controller itself doesn’t hold state, so a singleton makes sense.

Can we have two @RequestBody?

You cannot use two @RequestBody as it can bind to a single object only (the body can be consumed only once). As Luke explained the easiest would be to create one object that will capture all the relevent data, and than create the objects you have in the arguments.

What are REST API in Java?

The term REST stands for REpresentational State Transfer. It is an architectural style that defines a set of rules in order to create Web Services. In a client-server communication, REST suggests to create an object of the data requested by the client and send the values of the object in response to the user.

Is @ResponseBody required?

You can see that if you use Spring MVC @Controller annotation to create a RESTful response you need to annotate each method with the @ResponseBody annotation, which is not required when you use @RestController. It not only makes your code more readable but also saves a couple of keystrokes for you.

Is @RequestBody mandatory?

With Spring’s latest version, if you use @RequestBody annotation, it makes client to send body all the time without making it optional. I tried @RequestBody (required=false) but that didn’t work & still my request comes as null.

Can I 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).

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.

Can we use @component instead of controller?

Instead of using @Component on a controller class in Spring MVC, we use @Controller, which is more readable and appropriate. … Even if you replace @Controller annotation with @Compoenent, Spring can automatically detect and register the controller class but it may not work as you expect with respect to request mapping.

What is ResponseBody?

@ResponseBody is a Spring annotation which binds a method return value to the web response body. It is not interpreted as a view name. It uses HTTP Message converters to convert the return value to HTTP response body, based on the content-type in the request HTTP header.

What are REST API calls?

It is a set of rules that allow programs to talk to each other. The developer creates the API on the server and allows the client to talk to it. REST determines how the API looks like. It stands for “Representational State Transfer”. It is a set of rules that developers follow when they create their API.