abstract class Vehicle {
    private int maxSpeed;
    //...
}
 
class Car extends Vehicle {
    private int cargoCapacityInLiter;
    //...
}
 
class Plane extends Vehicle {
    private int wingspanInmeter;
    //...
}

class Benz extends Car {
    private int logoSize;
    //...
}

我知道使用 RuntimeTypeAdapterFactory 我们可以解决 Gson 的序列化/反序列化一级扩展，但我们如何实现如上例所示的二级扩展