Java，获取包含类的Class对象，而不是Runtime Class

Question

Consider this Java code

class A{
 //@returns Class object this method is contained in
 // should be A in this case
 public Class<?> f() {
   return getClass();
 }
}

class B extends A {}

B b = new B();

System.out.println(b.f());
//output -- B.class (Wrong, should be A.class)

inside f() i can't use getClass() because that will give me the runtype, which is B . I'm looking for a way to get the Class object of the class f() is inside (Without mentioning A explicitly, obviously)

Answer 1

new Object() {}.getClass().getEnclosingClass() . But please don't!

Answer 2

You can use exception stack trace facility to do something like this:

public String f() {
    Exception E = new Exception();
    E.fillInStackTrace();
    return E.getStackTrace()[0].getClassName(); // load it if you need to return class
}

Answer 3

I would have to say it would be much simpler and more clear to simply return A.class as @mmyers suggested. There is not much point in trying to derive it at runtime if you don't actually want the runtime value. The only issue that comes up is if you refactor the name of the class and another with the same name happens to exist, in the same package.

I would take that chance for the sake of clarity in the code now.

Answer 4

您可以使用

class.getMethod("f",parameterTypes).getDeclaringClass()

Answer 5

I know you said you didn't want to mention A.class explicitly

class A {        
    public Class<?> f() {
        return A.class;
    }   
}

but I'm struggling to find a use case where the above code isn't satisfactory.