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`@RestController` vs `@Controller` — what changes?

Tags

#restcontroller#controller#spring-mvc

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Answer

`@RestController` is basically `@Controller` + `@ResponseBody`, so methods return the response body (often JSON) directly. `@Controller` is typically used for server-rendered views/templates.

Advanced answer

Deep dive

`@Controller` is an MVC controller. By default, a method returning `String` is treated as a **view name** and rendered via a view resolver (Thymeleaf, JSP, etc.).

`@RestController` applies `@ResponseBody` to every handler method, meaning:

return values are written to the HTTP response body,
message converters (e.g., Jackson) serialize objects to JSON,
content negotiation selects the response format.

Practical patterns

Use `@RestController` for APIs returning DTOs.
Use `@Controller` for server-side rendered pages.
If you must mix, be explicit with `@ResponseBody` / `ResponseEntity`.

Examples

JSON:

@RestController
class UserApi {
  @GetMapping("/users/{id}")
  UserDto get(@PathVariable long id) { /* ... */ }
}

View:

@Controller
class PageController {
  @GetMapping("/login")
  String loginPage() { return "login"; }
}

Common pitfalls

Related questions

`@RestController` vs `@Controller`: what’s the difference?

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`@RequestParam` vs `@PathVariable` — when do you use which?

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