CODEWITHSUNDEEP
javajsonjackson
Olly
Olly

Reputation: 371

Mapping JSON with varying object name

I'm quite new to JSON, and I've looked around trying to work out what to do but not sure if I fully understand. I am making an external API call returning:

2015-12-21 01:22:09 INFO  RiotURLSender:60 - Total json: 
{"USERNAME":{"profileIconId":984,"revisionDate":1450655430000,"name":"USERNAME2","id":38584682,"summonerLevel":30}}

Where 'USERNAME' (And USERNAME2 - which can be very slightly different to USERNAME) will vary depending on what you pass the call's parameters. I was using Jackson Object Mapper to map the individual values within the USERNAME object - but didn't realise I had to map the object as well.

I've been using annotations in the DTOs like:

@JsonProperty("profileIconId")
private Long profileIconId;

and mapping using:

summonerRankedInfoDTO = mapper.readValue(jsonString, SummonerRankedInfoDTO.class);

How do I map using a value of USERNAME which is changing every single time?

Also this seems a bit odd, is this bad practice to have the actual varying key rather than just have the same key and different value?

Thanks

Upvotes: 2

Views: 3184

Answers (2)

Sunny
Sunny

Reputation: 111

you can use following mentioned annotation @JsonAnyGetter And @JsonAnySetter. Add this code into ur domain class. So any non-mapped attribute will get populated into "nonMappedAttributes" map while serializing and deserializing the Object.

@JsonIgnore
protected Map<String, Object> nonMappedAttributes;

@JsonAnyGetter
public Map<String, Object> getNonMappedAttributes() {
    return nonMappedAttributes;
}

@JsonAnySetter
public void setNonMappedAttributes(String key, Object value) {
    if (nonMappedAttributes == null) {
        nonMappedAttributes = new HashMap<String, Object>();
    }
    if (key != null) {
        if (value != null) {
            nonMappedAttributes.put(key, value);
        } else {
            nonMappedAttributes.remove(key);
        }
    }

}

Upvotes: 3

Jonathan Maddox
Jonathan Maddox

Reputation: 41

You should try to keep the keys the exact same if possible and change values, otherwise you'll have to change your JSON. Since JSON returns a value from the key, the value can change to anything it wants, but you'll be able to return it from the key. This doesn't work the other way around though.

Anyway to your question, you may have a little better luck using something like the GSON library, its pretty simple to use.

You can create the instance and pass it the JSON string:

Gson gson = new Gson();
JsonObject obj = gson.fromJson(JSON_DOCUMENT, JsonObject.class);

Then you can get certain elements from that now parsed JSON object.

For example, in your JSON string, username returns another JSON element, so you can do:

JsonObject username = obj.get("USERNAME").getAsJsonObject();

Then just repeat the same steps from there to get whatever value you need. So to get the name which returns "USERNAME2":

username.get("name").getAsString();

Coming together with:

JsonObject obj = gson.fromJson(JSON_DOCUMENT, JsonObject.class);
JsonObject username = obj.get("USERNAME").getAsJsonObject();
username.get("name").getAsString();

Upvotes: 1

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