如何确定某个类是否在Java中扩展了另一个类？

Question

在Java中，我该如何确定类扩展了哪些类？

public class A{
}

public class B extends A{
}

public class C extends A{
}

public class D{
}

public class E extends B{
}

public class doSomething{

    public void myFunc(Class cls){
         //need to check that cls is a class which extends A
         //i.e. B, C and E but not A or D
    }
}

会cls.getSuperClass()做我需要的吗？

Answer 1

该getSuperClass()方法将失败，E因为它的直接超类不是A，而是B。宁可使用Class#isAssignableFrom()。

public void myFunc(Class cls){
     //need to check that cls is a class which extends A
     //i.e. B, C and E but not A or D

     if (cls != A.class && A.class.isAssignableFrom(cls)) {
         // ...
     }
}