The difference between `@RestController` and `@Controller`

The difference between @RestController and @Controller in Spring Framework lies mainly in how they handle HTTP responses.

1. @Controller

• Used for: Traditional MVC (Model-View-Controller) web applications.
• Returns: Usually returns a View (like JSP, Thymeleaf, etc.).
• ResponseBody: If you want to return JSON/XML instead of a view, you must use @ResponseBody on the method.

Example:

@Controller
public class MyController {

    @GetMapping("/hello")
    public String hello(Model model) {
        model.addAttribute("message", "Hello, World!");
        return "hello";  // returns a view named "hello"
    }

    @GetMapping("/api")
    @ResponseBody
    public String api() {
        return "This is JSON or plain text";
    }
}

2. @RestController

• Used for: RESTful web services (APIs).
• Returns: Automatically returns JSON or XML responses.
• Behavior: It is a convenience annotation that combines @Controller and @ResponseBody. So every method returns the body directly, not a view.

Example:

@RestController
public class MyRestController {

    @GetMapping("/hello")
    public String hello() {
        return "Hello, REST!";  // returns as JSON or plain text
    }
}

Summary: