Question 108936 in Json Question posted in
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Deserialise a dynamic JSON into a java object

Is it possible to somehow convert a dynamic JSON object (No fixed schema) into a Java object?

For example, for first time, I can get the following JSON object at runtime:

{
  "addressDetails": {
    "homeAddresses": [
      {
        "houseNo": "1",
        "city": "2"
      }
    ],
    "currentAddress": {
      "houseNo": "1",
      "city": "2"
    }
  },
  "personalDetails": {
    "birthDetails": {
      "birthPlace": "1",
      "birthMonth": "2"
    }
  },
  "confidentialDetails": {
    "birthDetails": {
      "birthPlace": "1",
      "birthMonth": "2"
    }
  },
  "bankingDetails": {
    "bankName": "1",
    "bankAccountNo": 2
  }
}

The next time, maybe with something like this:

{
  "confidentialDetails": {
    "birthDetails": {
      "birthPlace": "1",
      "birthMonth": "2"
    }
  },
  "personalDetails": {
    "birthDetails": {
      "birthPlace": "1",
      "birthMonth": "2"
    }
  }
}

How can I handle all these variations? Is it possible with Jackson/Gson or some other library?

I expect to find a solution which is very generic and can handle the different variations in JSON object gracefully.

Tags:

3

Answers


  1. 0

    You can deserialize it into Map<String,Object>

    public static void main(String[] args) throws JsonProcessingException {
    ObjectMapper objectMapper = new ObjectMapper(); // This is an expensive operation. objectMapper is thread-safe so it cane be shared
    String inboundJsonStr = "{"name":"Jane Doe","id":2,"is_active":null}";
    Map<String,Object> jsonObject = objectMapper.readValue(inboundJsonStr, Map.class);
}

    ObjectMapper is from Jackson library

    sidenote: Java is a typed language. If you do this, you will loose some benefits of the type check that language offers

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  2. 0

    I don’t know if I understand your question. However, you can try to define all possible JSON objects into one object and then serialize them using GSON or another JSON conversion tool.
    like this:

    public class Parent {
    private AddressDetails addressDetails;
    private PersonalDetails personalDetails;
    private PersonalDetails confidentialDetails;
}
class AddressDetails{
    private List<HomeAddresses> homeAddresses;
    private List<CurrentAddress> currentAddresses;
}
class Addresses{
    private String houseNo;
    private String city;
}
class BirthDetails{
    private String birthDetails;
    private String birthMonth;
}
class HomeAddresses extends Addresses{
}
class CurrentAddress extends Addresses{
}
class PersonalDetails extends BirthDetails{
}

    Or if there are too many types to define, you can simply convert the JSON string to a JSON object for use
    like this:

    String jsonStr = "{n" +
            "  "addressDetails": {n" +
            "    "homeAddresses": [n" +
            "      {n" +
            "        "houseNo": "1",n" +
            "        "city": "2"n" +
            "      }n" +
            "    ],n" +
            "    "currentAddress": {n" +
            "      "houseNo": "1",n" +
            "      "city": "2"n" +
            "    }n" +
            "  },n" +
            "  "personalDetails": {n" +
            "    "birthDetails": {n" +
            "      "birthPlace": "1",n" +
            "      "birthMonth": "2"n" +
            "    }n" +
            "  },n" +
            "  "confidentialDetails": {n" +
            "    "birthDetails": {n" +
            "      "birthPlace": "1",n" +
            "      "birthMonth": "2"n" +
            "    }n" +
            "  },n" +
            "  "bankingDetails": {n" +
            "    "bankName": "1",n" +
            "    "bankAccountNo": 2n" +
            "  }n" +
            "}";
    JSONObject jsonObject = JSONUtil.parseObj(jsonStr);
    JSONObject addressDetails = jsonObject.get("addressDetails", JSONObject.class);
    JSONArray homeAddresses = addressDetails.get("homeAddresses", JSONArray.class);
    JSONObject object = homeAddresses.get(0, JSONObject.class);
    System.out.println(object.get("houseNo"));
    System.out.println(object.get("city"));
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  3. 0

    It is possible to do that with Jackson library. Just read the JSON and remove data with addressDetails and bankingDetails keys.

    import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.databind.node.ObjectNode;
import java.io.IOException;

public class JavaApplication {

    public static void main(String[] args) throws IOException {
        ObjectMapper mapper = new ObjectMapper();
        mapper.enable(SerializationFeature.INDENT_OUTPUT);

        ObjectNode jsonData = (ObjectNode) mapper.readTree("{"addressDetails":{"homeAddresses":[{"houseNo":"1","city":"2"}],"currentAddress":{"houseNo":"1","city":"2"}},"personalDetails":{"birthDetails":{"birthPlace":"1","birthMonth":"2"}},"confidentialDetails":{"birthDetails":{"birthPlace":"1","birthMonth":"2"}},"bankingDetails":{"bankName":"1","bankAccountNo":2}}");
        jsonData.remove("addressDetails");
        jsonData.remove("bankingDetails");
        System.out.println(mapper.writeValueAsString(jsonData));
    }
}

    The output will be:

    {
  "personalDetails" : {
    "birthDetails" : {
      "birthPlace" : "1",
      "birthMonth" : "2"
    }
  },
  "confidentialDetails" : {
    "birthDetails" : {
      "birthPlace" : "1",
      "birthMonth" : "2"
    }
  }
}
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