How Do I Put Generic Type For Gson's Typetoken?

EDIT After experimenting for a while, I know my problem is. I can't put generic type inside TypeToken (Type type = new TypeToken>(){}.getType();). Whe

Solution 1:

You have to specify the Type explicitly. There's type erasure in Java, which basically means that at runtime all instances of T are replaced with Object.

You should either write three different deserializers for different response types(POJOA, POJOB, POJOC) or write a generic one. Something like this should work:

publicclassGenericConverterimplementsJsonDeserializer<CustomResponse<?>> {
    private Type typeOfResponse;

    publicGenericConverter(Type typeOfResponse) {
        this.typeOfResponse = typeOfResponse;
    }

    public CustomResponse deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext ctx) {
        CustomResponseresponse=newCustomResponse();
        response.setResponse(ctx.deserialize(json.getAsJsonObject().get("response"), typeOfResponse));
        return response;
    }
}

And register it appropriately:

gsonBuilder.registerTypeAdapter(new TypeToken<CustomResponse<POJOA>>(){}.getType(),
        new GenericConverter(POJOA.class));
gsonBuilder.registerTypeAdapter(new TypeToken<CustomResponse<POJOB>>(){}.getType(),
        new GenericConverter(POJOB.class));
gsonBuilder.registerTypeAdapter(new TypeToken<CustomResponse<POJOC>>(){}.getType(),
        new GenericConverter(POJOC.class));