如何使用Java反射读取泛型参数的类类型

Question

I have a class BaseClass<X, Y, Z> . And I implement the class as SuperCar implements BaseClass<Color, Engine, Foo> . So now i need to get those X,Y,Z values by using reflection on SuperCar class. Is this possible ?

Answer 1

You can inspect the type parameters for the superclass, having the Class of the SuperCar :

SuperCar car = new SuperCar();
ParameterizedType parameterizedType = (ParameterizedType) car.getClass().getGenericSuperclass();
Type[] superClassTypes = parameterizedType.getActualTypeArguments();
for (Type type : superClassTypes) {
    System.out.println(type.getTypeName());
}

This should give you:

Color
Engine
Foo

Answer 2

i guess you want to have something like this:

ParameterizedType types = (ParameterizedType) SuperCar.class.getGenericInterfaces()[0];
for (Type type : types.getActualTypeArguments()) {
    Class<?> cl = (Class<?>) type;
    System.out.println(cl.getName());
}

instead of printing the name you can do whatever you like with it