java instanceof方法

基本用法

instanceof与getClass的区别

public class Test

{

	public static void testInstanceof(Object x)

	{

		System.out.println("x instanceof Parent:  "+(x instanceof Parent));

		System.out.println("x instanceof Child:  "+(x instanceof Child));

		System.out.println("x getClass Parent:  "+(x.getClass() == Parent.class));

		System.out.println("x getClass Child:  "+(x.getClass() == Child.class));

	}

	public static void main(String[] args) {

		testInstanceof(new Parent());

		System.out.println("---------------------------");

		testInstanceof(new Child());

	}

}

class Parent {

}

class Child extends Parent {

}

/*

输出:

x instanceof Parent:  true

x instanceof Child:  false

x getClass Parent:  true

x getClass Child:  false

---------------------------

x instanceof Parent:  true

x instanceof Child:  true

x getClass Parent:  false

x getClass Child:  true

*/

　　从程序输出可以看出,instanceof进行类型检查规则是:你属于该类吗？或者你属于该类的派生类吗？而通过getClass获得类型信息采用==来进行检查是否相等的操作是严格的判断。不会存在继承方面的考虑