[java] Jackson 직렬화 : 빈 값 무시 (또는 null)

현재 jackson 2.1.4를 사용하고 있으며 객체를 JSON 문자열로 변환 할 때 필드를 무시하는 데 문제가 있습니다.

변환 할 객체로 작동하는 클래스는 다음과 같습니다.

public class JsonOperation {

public static class Request {
    @JsonInclude(Include.NON_EMPTY)
    String requestType;
    Data data = new Data();

    public static class Data {
        @JsonInclude(Include.NON_EMPTY)
        String username;
        String email;
        String password;
        String birthday;
        String coinsPackage;
        String coins;
        String transactionId;
        boolean isLoggedIn;
    }
}

public static class Response {
    @JsonInclude(Include.NON_EMPTY)
    String requestType = null;
    Data data = new Data();

    public static class Data {
        @JsonInclude(Include.NON_EMPTY)
        enum ErrorCode { ERROR_INVALID_LOGIN, ERROR_USERNAME_ALREADY_TAKEN, ERROR_EMAIL_ALREADY_TAKEN };
        enum Status { ok, error };

        Status status;
        ErrorCode errorCode;
        String expiry;
        int coins;
        String email;
        String birthday;
        String pictureUrl;
        ArrayList <Performer> performer;
    }
}
}

그리고 그것을 변환하는 방법은 다음과 같습니다.

ObjectMapper mapper = new ObjectMapper();
mapper.setVisibility(PropertyAccessor.FIELD, Visibility.ANY);

JsonOperation subscribe = new JsonOperation();

subscribe.request.requestType = "login";

subscribe.request.data.username = "Vincent";
subscribe.request.data.password = "test";


Writer strWriter = new StringWriter();
try {
    mapper.writeValue(strWriter, subscribe.request);
} catch (JsonGenerationException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
} catch (JsonMappingException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
} catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
}

Log.d("JSON", strWriter.toString())

출력은 다음과 같습니다.

{"data":{"birthday":null,"coins":null,"coinsPackage":null,"email":null,"username":"Vincent","password":"test","transactionId":null,"isLoggedIn":false},"requestType":"login"}

이러한 null 값을 피하려면 어떻게해야합니까? “구독”목적으로 만 필요한 정보를 얻고 싶습니다!

내가 찾는 결과는 다음과 같습니다.

{"data":{"username":"Vincent","password":"test"},"requestType":"login"}

또한 @JsonInclude (Include.NON_NULL) 시도하고 모든 변수를 null로 설정했지만 작동하지 않았습니다! 도와 주셔서 감사합니다!

답변

@JsonInclude(Include.NON_NULL) //or Include.NON_EMPTY, if that fits your use case 
public static class Request {
  // ...
}

@JsonSerialize(include = JsonSerialize.Inclusion.NON_NULL) // or JsonSerialize.Inclusion.NON_EMPTY

objectMapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);

@JsonSerialize(include=JsonSerialize.Inclusion.NON_NULL)

@JsonInclude(JsonInclude.Include.NON_NULL)

@JsonInclude(JsonInclude.Include.NON_NULL)

@JsonInclude(JsonInclude.Include.NON_NULL)

@JsonInclude(JsonInclude.Include.NON_NULL)

objectMapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);

public class SampleDTO {

    String username;
    String email;
    String password;
    String birthday;
    String coinsPackage;
    String coins;
    String transactionId;
    boolean isLoggedIn;

    // getters/setters
}

import com.google.gson.Gson;

public class Test {

    public static void main(String[] args) {
        SampleDTO objSampleDTO = new SampleDTO();
        Gson objGson = new Gson();
        System.out.println(objGson.toJson(objSampleDTO));
    }
}

{"isLoggedIn":false}