isAssignableFrom()：

• 用法：A.isAssignableFrom(B) 用于判定A类或接口是否时B类或接口的同类或者父类。

instanceof：

• 用法：A instanceof B 用于判定A类是否是B类的同类或者子类。

public class IsAssignableFromDemo {
    static class Father{}
    static class Child extends Father{}

    public static void main(String[] args) {
        Father father = new Father();
        Child child = new Child();
        //instanceof 用法
        boolean b1 = father instanceof Child;
        boolean b2 = child instanceof Father;
        boolean b3 = child instanceof Child;
        System.out.println(b1); 
        System.out.println(b2);
        System.out.println(b3);
        //isAssignableFrom用法
        boolean a1 = Father.class.isAssignableFrom(Child.class);
        boolean a2 = Child.class.isAssignableFrom(Father.class);
        boolean a3 = Father.class.isAssignableFrom(Father.class);
        System.out.println(a1);
        System.out.println(a2);
        System.out.println(a3);
	//输出
		false
		true
		true
		true
		false
		true
    }
}