Spring · 웹과 REST 컨트롤러

// 1) 객체만 반환 → 200 OK + JSON 본문 (Jackson 직렬화)
@GetMapping("/{id}")
public UserDTO get(@PathVariable Long id) { ... }

// 2) ResponseEntity 로 상태코드/헤더/본문 직접 제어
@PostMapping("")
public ResponseEntity<UserDTO> create(@RequestBody UserDTO req) {
  UserDTO saved = ...;
  return ResponseEntity.status(HttpStatus.CREATED).body(saved); // 201
}

@DeleteMapping("/{id}")
@ResponseStatus(HttpStatus.NO_CONTENT)   // 본문 없이 204
public void delete(@PathVariable Long id) { ... }

@RestControllerAdvice           // = @ControllerAdvice + @ResponseBody
public class GlobalExceptionHandler {

  @ExceptionHandler(NotFoundException.class)
  public ResponseEntity<ErrorDTO> handleNotFound(NotFoundException e) {
    return ResponseEntity.status(HttpStatus.NOT_FOUND)
        .body(new ErrorDTO(e.getMessage()));   // 404 + JSON
  }
}

@ExceptionHandler(NotFoundException.class)
public ProblemDetail handle(NotFoundException e) {
  ProblemDetail pd = ProblemDetail
      .forStatusAndDetail(HttpStatus.NOT_FOUND, e.getMessage());
  pd.setTitle("자원을 찾을 수 없음");
  return pd;   // RFC 7807 형식 JSON 으로 응답
}

import jakarta.validation.Valid;          // Jakarta EE 10 (javax 아님)
import org.springframework.data.domain.Page;
import org.springframework.data.domain.Pageable;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;

@RestController
@RequestMapping("/api/users")            // 클래스 공통 경로
@RequiredArgsConstructor                 // final 필드 생성자 주입
public class UserEndpoint {

  private final UserService userService;

  // 목록: GET /api/users?page=0&size=20
  @GetMapping("")
  public Page<UserDTO> list(@RequestParam(required = false) String keyword,
                            Pageable pageable) {
    return userService.search(keyword, pageable);   // 객체 반환 → JSON
  }

  // 단건: GET /api/users/7
  @GetMapping("/{id}")
  public UserDTO get(@PathVariable Long id) {
    return userService.get(id);
  }

  // 생성: POST /api/users  (본문 JSON → DTO, 검증)
  @PostMapping("")
  public ResponseEntity<UserDTO> create(@Valid @RequestBody UserDTO req) {
    UserDTO saved = userService.create(req);
    return ResponseEntity.status(HttpStatus.CREATED).body(saved);  // 201
  }

  // 수정: PUT /api/users/7
  @PutMapping("/{id}")
  public UserDTO update(@PathVariable Long id,
                        @Valid @RequestBody UserDTO req) {
    return userService.update(id, req);
  }

  // 삭제: DELETE /api/users/7  (본문 없이 204)
  @DeleteMapping("/{id}")
  @ResponseStatus(HttpStatus.NO_CONTENT)
  public void delete(@PathVariable Long id) {
    userService.delete(id);
  }
}

// 전역 예외 처리 — 모든 컨트롤러의 예외를 한 곳에서
@RestControllerAdvice
public class GlobalExceptionHandler {

  @ExceptionHandler(NotFoundException.class)
  public ResponseEntity<ProblemDetail> handleNotFound(NotFoundException e) {
    ProblemDetail pd = ProblemDetail
        .forStatusAndDetail(HttpStatus.NOT_FOUND, e.getMessage());
    return ResponseEntity.status(HttpStatus.NOT_FOUND).body(pd);   // 404
  }
}