铸造扩展相同原始类的子类 [英] Casting subclasses extending the same original class

问题描述

如何在java中投放两个扩展类？

How can I cast two extends class like that in java?

    class B extends Object{

    }

    class C extends Object{

    }

    B b = new B();

    C c = (C)b;//Cannot cast from B to C

推荐答案

不能。考虑稍微重命名：

You can't. Consider a slight rename:

class Ford extends Car{

}
class Chevrolet extends Car{

}

Ford ford = new Ford();

Chevrolet chevrolet = (Chevrolet) ford;

两者都是一辆车，所以你可以说

Both are, however, a Car so you can say

Car car = ford;

但不能超过。

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