instanceof、isInstance、==、equals判断Class是否相等

instanceof 关键字 和 isInstance的用法相同

现在有一个类Base

public class Base {

}

public class Derived extends Base{

}

public class FamilyVsExactType {

	static void test(Object x) {
		System.out.println("Testing x of type=" + x.getClass());
		System.out.println("x instanceof Base=" + (x instanceof Base));
		System.out.println("x instanceof Derived=" + (x instanceof Derived));
		System.out.println("Base.isInstance(x)=" + Base.class.isInstance(x));
		System.out.println("Derived.isInstance(x)=" + Derived.class.isInstance(x));
		System.out.println("x.getClass() == Base.class=" + (x.getClass() == Base.class));
		System.out.println("x.getClass() == Derived.class=" + (x.getClass() == Derived.class));
		System.out.println("x.getClass.equals(Base.class)=" + (x.getClass().equals(Base.class)));
		System.out.println("x.getClass.equals(Derived.class)=" + (x.getClass().equals(Derived.class))); } public static void main(String[] args) {
		test(new Base());
		test(new Derived());
	}
}

== 和 equals比较的实际的Class类，没有考虑继承，instanceof 和 isInstance考虑继承

Testing x of type=class com.my.rest.six.Base

x instanceof Base=true

x instanceof Derived=false

Base.isInstance(x)=true

Derived.isInstance(x)=false

x.getClass() == Base.class=true

x.getClass() == Derived.class=false

x.getClass.equals(Base.class)=true

x.getClass.equals(Derived.class)=false

Testing x of type=class com.my.rest.six.Derived

x instanceof Base=true

x instanceof Derived=true

Base.isInstance(x)=true

Derived.isInstance(x)=true

x.getClass() == Base.class=false

x.getClass() == Derived.class=true

x.getClass.equals(Base.class)=false

x.getClass.equals(Derived.class)=true

引用自 《thinking in Java》第14章

文章来源: cxuan.blog.csdn.net，作者：程序员cxuan，版权归原作者所有，如需转载，请联系作者。

原文链接：cxuan.blog.csdn.net/article/details/79090322