Add parent variables inside an json object while deserialize in jackson

I wanted to add extended class variables inside and jsonobject during deserialization in jackson.

ParentResponse Class :

@JsonInclude(value = Include.NON_EMPTY)
public class ParentResponse extends DefaultResponse {

@JsonProperty("parentname")
private String parentName;

// Getter and setter
}

DefaultResponse Class :

@JsonInclude(value = Include.NON_EMPTY)
public class DefaultResponse{

@JsonProperty("status")
private String status;

// Getter and Setter


@JsonProperty("responseInfo")
    public JSONObject responseInfo() {
        JSONObject jsonResponse = new JSONObject();
        jsonResponse.put("status", this.status);
        return new JSONObject();
    }
}

public class ResponseResource {
public static void main(String[] args) {
ParentResponse response = new ParentResponse();
        response.setStatus("success");
System.out.println(new ObjectMapper().writer().withDefaultPrettyPrinter().writeValueAsString(response));
}
}

This returns

{
    "status": "success",
}

My Requirement is

{
"responseInfo" : {
     "status" : "success"
}

Is this possible without customSerializer in jackson ?

Solution

Instead of your method responseInfo() you can declare a method returning a single-entry Map that would serve as a getter.

Note that this method doesn't require any data-binding annotations, it just needs to be named as a conventional getter in order to be treated by Jackson as a getter.

To avoid duplicating "status" property as a part of the attribute "responseInfo" and as a representation of the status field while serializing DefaultResponse you can either

Prevent Jackson accessing it by not exposing a getter (which might be not convenient because you might need a getter).
Another way is to annotate the field with @JsonIgnore, that would cause the status to be omitted during both serialization and desrialization.
The most flexible solution is to make use of the access attribute of the @JsonProperty annotation because it gives more control. For instance, if assigning access attribute to JsonProperty.Access.WRITE_ONLY it would be taken into account while deserializing JSON, but excluded during serialization.

That's how it might be implemented:

@JsonInclude(value = JsonInclude.Include.NON_EMPTY)
@Setter
@Getter
public static class DefaultResponse {
    @JsonProperty(value = "status", access = JsonProperty.Access.WRITE_ONLY)
    private String status;
    
    public Map<String, String> getResponseInfo() {
        return Map.of("status", status);
    }
}

Usage example:

public static void main(String[] args) throws JsonProcessingException {
    ParentResponse response = new ParentResponse();
    response.setStatus("success");
    
    String jsonResponse = new ObjectMapper().writer()
        .withDefaultPrettyPrinter()
        .writeValueAsString(response);
    
    System.out.println(jsonResponse);
}

Output:

{
  "responseInfo" : {
    "status" : "success"
  }
}