下投物体

/**来自 N o w J a v a . c o m - 时  代  Java**/


//package com.nowjava;


public class Main {

    @SuppressWarnings("unchecked")

    public static <T> T downcast(Class<T> klass, Object actual) {

        if (actual != null && klass.isAssignableFrom(actual.getClass()))

            return (T) actual;

        else

            return null;

    }

}