Java create custom exception class with specific status code

Tony :

In Spring Boot, I create custom exception class with specific status code, and I call it to throw exception with code: 100 and message: "No have content" at controller, but output still returns "status": 500 and "error": "Internal Server Error"

AppException.java

public class AppException extends RuntimeException {

    private static final long serialVersionUID = 1L;

    private final Integer code;

    public AppException(Integer code, String message) {
        super(message);
        this.code = code;
    }

    public Integer getCode() {
        return code;
    }
}

UserController.java

@RestController
@RequestMapping("/api/user")
public class UserController {

    @Autowired
    private UserService userService;

    @GetMapping()
    public ApiResponseDto getAllUsers(Pageable pageable) {
        Page<User> users = userService.getAllUsers(pageable);

        if (users.getSize() < 0) {
            throw new AppException(100, "No have content");
        }

        return new ApiResponseDto(HttpStatus.OK.value(), users);
    }

Actual Output:

{
    "timestamp": 1550987372934,
    "status": 500,
    "error": "Internal Server Error",
    "exception": "com.app.core.exception.AppException",
    "message": "No have content",
    "path": "/api/user"
}

My expectation:

{
    "timestamp": 1550987372934,
    "status": 100,
    "error": "No have content",
    "exception": "com.app.core.exception.AppException",
    "message": "No have content",
    "path": "/api/user"
}

Oleksii Zghurskyi :

In case you want to have global exception handling for your API, and prefer to have custom error responses, you can add @ControllerAdvice:

@ControllerAdvice
public class ApiExceptionHandler {

    @ExceptionHandler({ ApiException.class })
    protected ResponseEntity<ApiErrorResponse> handleApiException(ApiException ex) {
        return new ResponseEntity<>(new ApiErrorResponse(ex.getStatus(), ex.getMessage(), Instant.now()), ex.getStatus());
    }
}

// you can put any information you want in ApiErrorResponse 
public class ApiErrorResponse {

    private final HttpStatus status;
    private final String message;
    private final Instant timestamp;

    public ApiError(HttpStatus status, String message, Instant timestamp) {
        this.status= status;
        this.message = message;
        this.timestamp = timestamp;
    }

    public HttpStatus getStatus() { 
        return this.status; 
    }

    public String getMessage() {
        return this.message;
    }

    public Instant getTimestamp() {
        return this.timestamp;
    }
}

// your custom ApiException class
public class ApiException extends RuntimeException {

    private final HttpStatus status;

    public ApiException(HttpStatus status, String message) {
        super(message);
        this.status = status;
    }

    public HttpStatus getStatus() {
        return this.status;
    }
}