Not able to Parse JSON data to POJO

Question

I have JSON data with following structure. I have tried creating POJOs with same structure and with same names. I have taken a DTO which contains a list (of DTOs with structure of the numeral objects in the following JSON) and a String "Notice". I am not able to get the data in the DTO.

{
    "notice": "This API is in a pre-launch state, and will go through significant changes.",
    "1": {
        "next_renewal_date": "2014-08-01",
        "next_renewal_fee": {
            "price": "800.0",
            "currency": "USD"
        },
        "next_renewal_description": "1st Annuity - Official Fee",
        "next_per_claim_fee": {
            "price": "0.0",
            "currency": "USD",
            "free_claims": 0,
            "claim_type": "claims_count"
        },
        "next_agent_fee": {
            "price": "0.0",
            "currency": "USD"
        },
        "grace_period_end_date": "2015-02-01"
    },
    "2": {
        "next_renewal_date": "2018-08-01",
        "next_renewal_fee": {
            "price": "1800.0",
            "currency": "USD"
        },
        "next_renewal_description": "2nd Annuity - Official Fee",
        "next_per_claim_fee": {
            "price": "0.0",
            "currency": "USD",
            "free_claims": 0,
            "claim_type": "claims_count"
        },
        "next_agent_fee": {
            "price": "0.0",
            "currency": "USD"
        },
        "grace_period_end_date": "2019-02-01"
    }
}

POJO:

public class RenewalAPICallListDTO {
    private Map<Integer,JSONCallDto> apiCallList;

    public Map<Integer, JSONCallDto> getApiCallList() {
        return apiCallList;
    }
    public void setApiCallList(Map<Integer, JSONCallDto> apiCallList) {
        this.apiCallList = apiCallList;
    }
    private String notice;

    public String getNotice() {
        return notice;
    }
    public void setNotice(String notice) {
        this.notice = notice;
    }
}

Method call:

Gson gson = new Gson();
RenewalAPICallListDTO respDto = gson.fromJson(response1.toString(), RenewalAPICallListDTO.class);

Show your POJO and whatever you are using to parse the json. — dambros, Apr 04 '16 at 09:58
Gson gson = new Gson(); RenewalAPICallListDTO respDto = gson.fromJson(response1.toString(), RenewalAPICallListDTO.class); — Chirag Nangru, Apr 04 '16 at 10:00
public class RenewalAPICallListDTO { private Map apiCallList; public Map getApiCallList() { return apiCallList; } public void setApiCallList(Map apiCallList) { this.apiCallList = apiCallList; } private String notice; public String getNotice() { return notice; } public void setNotice(String notice) { this.notice = notice; } } — Chirag Nangru, Apr 04 '16 at 10:00
Edit your answer and add that information, with correct formatting. Here it is unreadable. — dambros, Apr 04 '16 at 10:01
JSONCallDto has further structure of the numbered objects in JSON Data — Chirag Nangru, Apr 04 '16 at 10:01
Like I said, edit your answer ans put the code in it, with correct formatting. Here in the comments it is unreadable. — dambros, Apr 04 '16 at 10:12
Your JSON does not match your POJO, so without a custom converter it will not work. You are using a Map but there is no JSONArrays in your JSON. Is it possible to edit your JSON or you have no control over it? — dambros, Apr 04 '16 at 10:22
That is the problem, the JSON I am getting is from a third party API and this is the structure which will be provided. I am getting value of "Notice", but cant get the repeated object. What do you mean by custom converter? — Chirag Nangru, Apr 04 '16 at 10:25
Yes I have tried that too.....but facing the same problem.... — Chirag Nangru, Apr 04 '16 at 10:34

score 0 · Answer 1 · answered Apr 04 '16 at 10:34

0

The json and POJO do not match. The attribute apiCallList is missing in your JSON string.

The structure should be like:

{
    "notice": "random string",
    "apiCallList": {
        "1": {
            "next_renewal_date": "2014-08-01",
             ...
        },
        "2": {
            "next_renewal_date": "2014-08-01",
             ....
        }
    }
}

answered Apr 04 '16 at 10:34

Rima

545
6
12

Yes, this should have solved the problem but I cant change the JSON. – Chirag Nangru Apr 04 '16 at 10:59

score 0 · Answer 2 · answered Apr 04 '16 at 11:02

0

I have found a way. Thanks for the help. I have converted the JSON into Hashmap using : Map data = mapper.readValue(json,Map.class); and then iterated the map, using the objects to populate POJOs.

answered Apr 04 '16 at 11:02

Chirag Nangru

21
6

score 0 · Accepted Answer · answered Apr 04 '16 at 11:05

What you are looking for can be achieve with Jackson with a custom deserializer, as the following:

public class CustomDeserializer extends JsonDeserializer<RenewalAPICallListDTO> {

    private static final ObjectMapper mapper = new ObjectMapper();

    static {
        mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
    }

    @Override
    public RenewalAPICallListDTO deserialize(JsonParser jp, DeserializationContext ctxt)
            throws IOException {


        JsonNode node = jp.getCodec().readTree(jp);

        Iterator<Entry<String, JsonNode>> nodeIterator = node.fields();

        RenewalAPICallListDTO dto = new RenewalAPICallListDTO();
        Map<Integer, JsonCallDto> map = new HashMap<>();

        while (nodeIterator.hasNext()) {
            Map.Entry<String, JsonNode> entry = nodeIterator.next();
            if (entry.getKey().equalsIgnoreCase("notice")) {
                dto.setNotice(entry.getValue().toString());
            } else {
                map.put(Integer.parseInt(entry.getKey()), mapper.readValue(entry.getValue().toString(), JsonCallDto.class));
            }
        }
        dto.setApiCallList(map);
        return dto;
    }

}

Usage:

public static void main(String[] args) throws Exception {

    ObjectMapper mapper = new ObjectMapper();
    SimpleModule module = new SimpleModule();
    module.addDeserializer(RenewalAPICallListDTO.class, new CustomDeserializer());
    mapper.registerModule(module);

    RenewalAPICallListDTO dto = mapper.readValue(JSON, RenewalAPICallListDTO.class);
}

The final dto will be correctly serialized like you want, even with the correct types already set.

Not able to Parse JSON data to POJO

3 Answers3