I want Generic class's "Class" with "Class variable"

Question

I want to get Generic class's type variable for JsonDeserialize.

Class Data<T> {
  private T data;
}

Class DataType {
  private String dummy;
}


Class dataTypeClass = DataType.class;


// I want get this.
Class dataClass = Data<dataTypeClass>.class;

I've tried it like this way, It doesn't work.

Could I get Data.class ??

Possible duplicate of [Get generic type of class at runtime](https://stackoverflow.com/questions/3403909/get-generic-type-of-class-at-runtime) — Kartik, May 29 '19 at 07:13
That's interesting. I could solve the problem in a hacky way that I wouldn't share with someone who wouldn't understand it, but I couldn't find anything where jackson helps with that. — kumesana, May 29 '19 at 08:58

score 1 · Accepted Answer · answered May 29 '19 at 07:19

1

If you're using Jackson as your library. You can just use TypeReference:

TypeReference<Data<DataType>> r = new TypeReference<Data<DataType>>() {};
...
Data<DataType> data = objectMapper.readValue(json, r);

This code will create a new anonymous sub class of TypeReference parameterized with <Data<DataType>>. This class internally uses a "hackaround" to get the generic parameter, which then is picked up by Jackson to deserialize your JSON.

answered May 29 '19 at 07:19

Lino

19,604
6
47
65

Could i get TypeReference from `Class variable` ?? – LKC May 29 '19 at 07:26
@LKC then you can just call `objectMapper.readValue(json, variable)` if you already have a `Class` – Lino May 29 '19 at 07:29

I want Generic class's "Class" with "Class variable"

1 Answers1