CODEWITHSUNDEEP
java
Crayl
Crayl

Reputation: 1911

Is there a way to convert a complex JSON to an object without creating a POJO?

I want to convert a JSON-String to an object. Normally I create an POJO and convert the String to a GSON or JSONObject to my POJO. But is there a better where I don't have to create an POJO?

The goal is to get an object where I can access the keys and values of the JSON... in whatever way, like jsonObject.getKey("foo").getProperty("bar").. or whatever :D

Upvotes: 1

Views: 545

Answers (1)

Sotirios Delimanolis
Sotirios Delimanolis

Reputation: 280132

Most JSON parser/generator libraries have a type for each of the JSON types.

Gson has JsonElement and its sub types. Here's an example where you can chain calls.

public static void main(String[] args) throws Exception {
    String jsonString = "{\"property1\":\"someValue\", \"arrayProperty\":[{\"first\":1234, \"second\":-13.123}, {\"nested\":\"so deep\"}], \"finally\":\"last\"}";
    Gson gson = new Gson();
    JsonElement element = gson.fromJson(jsonString, JsonElement.class);
    System.out.println(element);
    JsonObject jsonObject = element.getAsJsonObject(); // should test type before you do this

    System.out.println(jsonObject.get("arrayProperty").getAsJsonArray().get(0));
}

prints

{"property1":"someValue","arrayProperty":[{"first":1234,"second":-13.123},{"nested":"so deep"}],"finally":"last"}
{"first":1234,"second":-13.123}

The above is more or less implemented with a LinkedTreeMap for JsonObject and a List for JsonArray. It provides wrappers to access the elements as more JsonObject, JsonArray, JsonNull, and/or JsonPrimitive instances.

Upvotes: 2

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