[FIXED] When to use @Controller and when @RestController annotation in RESTApi based on Spring

Issue

I am new to learning Spring and I created a simple RestApi. Now in some tutorials I see that the controller class is sometimes annotated with @Controller and others are annotated with @RestController.

Can anyone clarify the differences for me? Thanks

Solution

It only took one quick google search for me to get a lot of answers. Also, this question has already been answered in another SO thread, found here.

But quickly summarized:

@Controller is used to annotate your controller class. When using @Controller you typically use it in combination with @ResponseBody. So you annotate your endpoint methods with @ResponseBody to let Spring know what return type to expect from that particular endpoint.

@Controller
public ControllerClass {

   @GetMapping("/greetings")
   @ResponseBody
   private String someEndpoint(){
       return "hey";
   }

}

@RestController simply combines @Controller and @ResponseBody. So you don't need to annotate your endpoint methods with @ResponseBody. A single anntoation of your controller class will do the magic. The return type of the endpoint methods are used as response body.

@RestController
public ControllerClass {

   @GetMapping("/greetings")
   private String someEndpoint(){
       return "hey";
   }

}

Answered By - Domiii
Answer Checked By - Timothy Miller (JavaFixing Admin)