ResponseEntity

What is ResponseEntity?

HttpEntity

Spring Framework에서 제공하는 클래스 중 HttpEntity라는 클래스가 존재한다.

이것은 HttpHeader와 HttpBody를 포함하는 클래스이다.

public class HttpEntity<T> {

	private final HttpHeaders headers;

	@Nullable
	private final T body;
}

xEntity

HttpEntity를 상속받아 구현한 클래스가 RequestEntity , ResponseEntity 이다.

여기서 ResponseEntity는 요청에 대한 응답 데이터를 포함하는 클래스이기에 HttpStatus, HttpHeaders, HttpBody를 포함한다.

public class RequestEntity<T> extends HttpEntity<T>

public class ResponseEntity<T> extends HttpEntity<T>

ResponseEntity

public class ResponseEntity<T> extends HttpEntity<T> {

	private final Object status;


	/**
	 * Create a {@code ResponseEntity} with a status code only.
	 * @param status the status code
	 */
	public ResponseEntity(HttpStatus status) {
		this(null, null, status);
	}

	/**
	 * Create a {@code ResponseEntity} with a body and status code.
	 * @param body the entity body
	 * @param status the status code
	 */
	public ResponseEntity(@Nullable T body, HttpStatus status) {
		this(body, null, status);
	}

	/**
	 * Create a {@code ResponseEntity} with headers and a status code.
	 * @param headers the entity headers
	 * @param status the status code
	 */
	public ResponseEntity(MultiValueMap<String, String> headers, HttpStatus status) {
		this(null, headers, status);
	}

	/**
	 * Create a {@code ResponseEntity} with a body, headers, and a status code.
	 * @param body the entity body
	 * @param headers the entity headers
	 * @param status the status code
	 */
	public ResponseEntity(@Nullable T body, @Nullable MultiValueMap<String, String> headers, HttpStatus status) {
		this(body, headers, (Object) status);
	}

	/**
	 * Create a {@code ResponseEntity} with a body, headers, and a raw status code.
	 * @param body the entity body
	 * @param headers the entity headers
	 * @param rawStatus the status code value
	 * @since 5.3.2
	 */
	public ResponseEntity(@Nullable T body, @Nullable MultiValueMap<String, String> headers, int rawStatus) {
		this(body, headers, (Object) rawStatus);
	}

생성자들을 보면 body, headers, status 세가지를 다루는 객체임을 알 수 있다.

Message Class & StatusEnum

ResponseEntity에 사용할 속성들을 객체로서 관리하자.

MessageClass

@Data
public class Message {
    private Status status;
    private String message;
    private Object data;

    public Message(Status status, String message, Object data) {
        this.status = status;
        this.data = data;
        this.message = message;
    }
}

StatusEnum

public enum Status {

    BAD_REQUEST(400, "BAD_REQUEST"),
    INTERNAL_SERER_ERROR(500, "INTERNAL_SERVER_ERROR"),
    NOT_FOUND(404, "NOT_FOUND"),
    OK(200, "OK") // 필요에 따라 커스텀하자
    ;

    int statusCode;
    String code;

    Status(int statusCode, String code) {
        this.statusCode = statusCode;
        this.code = code;
    }
}

Usage

@GetMapping(path="/")
@ResponseBody
public ResponseEntity<Message> getAllUserAuth() {
        List<UserAuth> userAuthsReadResult = userAuthService.getAllUserAuthInfo();

        Message responseMessage = new Message(StatusEnum.OK, "Get All Boards Success!", userAuthsReadResult);
        HttpHeaders headers = getHeader("application","json","UTF-8");

        return new ResponseEntity<>(responseMessage, headers, HttpStatus.OK);

    }
    
public static HttpHeaders getHeader(String type, String subtype, String charsetName) {
        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(new MediaType(type, subtype, Charset.forName(charsetName)));

        return headers;
    }