Retrofit Response Array or Object either

Question

In the first case when it returns success true, everything works, the problem when it gets success boolean is false, then the error:

How Retrofit Response Array or Object either.

Expected BEGIN_OBJECT but was BEGIN_ARRAY at line 1 column 26 path $ .data

Can it be done with one reponse class?

Json response:

{
  "success": true,
  "data": {
    "message": "User created",
  }
}

Json response:

{
  "success": false,
  "data": [
    {
      "code": "existing_user_login",
      "message": "User Exist !"
    }
  ]
}

Code:

public class Response {
    public Boolean success;
    public Data data;

    public Boolean isSuccess() { return success; }

    public Data getData() {
        return data;
    }

    public class Data {
        public String code;
        public String message;
        public String getMessage() { return message; }
        public String getCode() { return code; }
    }
}

score 0 · Answer 1 · edited Jul 08 '21 at 02:13

Using ObjectMapper you can do it by configuring deserialization features as below:

// import com.fasterxml.jackson.databind.ObjectMapper;
ObjectMapper objMapper = new ObjectMapper();
// this is to accept single element as array
objMapper.configure(DeserializationFeature.ACCEPT_SINGLE_VALUE_AS_ARRAY, true);
// this is to handle if any property is missing
objMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
Response resp = objMapper.readValue(jsonString, Response.class);

score 0 · Answer 2 · answered Jul 07 '21 at 02:23

you could use Object data first, and judge it before use it, like following:

public class Response {
    public Boolean success;
    public Object data;

    public Boolean isSuccess() { return success; }

    public Object getData() {
        if(data instanceof Data){
            //do something
        }else if (data instanceof List) {
            //do something
        }else {
            //do something
        }
        return data;
    }

    public class Data {
        public String code;
        public String message;
        public String getMessage() { return message; }
        public String getCode() { return code; }
    }
}

Retrofit Response Array or Object either

2 Answers2