当一个对象作为类型超类传入时，有没有办法检索子类的类型？

Question

If I had a method signature

public void myMethod(SuperClass s){
}

and SuperClass has three subclasses, is there any way within myMethod I can get the class name of the subclass which was passed in?

Not sure if it's important, but SuperClass is abstract.

Answer 1

is there any way within myMethod I can get the class name of the subclass which was passed in?

Yes, by using the getClass method :

public void myMethod(SuperClass s){
    System.out.println(s.getClass());
}

---

Remark 1:

This does however sound to me like a Bad Design™.

Whatever you want to do in myMethod consider having a method for it in SuperClass (provide a meaningful default implementation, or make it abstract to force subclasses to implement the method) and call this method on s in your method:

public void myMethod(SuperClass s){
    s.abstractMethod();
}

Remark 2:

If myMethod s logic is seemingly unrelated to the purpose of the SuperClass and you don't want to put the myMethod code inside this class, consider implementing the visitor pattern instead.