在Java中比较类类型 [英] Comparing Class Types in Java
问题描述
我想比较Java中的类类型。
I want to compare the class type in Java.
我想我可以这样做:
class MyObject_1 {}
class MyObject_2 extends MyObject_1 {}
public boolean function(MyObject_1 obj) {
if(obj.getClass() == MyObject_2.class) System.out.println("true");
}
我想比较,如果传递给函数的obj被扩展MyObject_1或不。
但是这不工作。看起来像getClass()方法和.class给出不同类型的信息。
I wanted to compare in case if the obj passed into the function was extended from MyObject_1 or not. But this doesn't work. It seems like the getClass() method and the .class gives different type of information.
如何比较两个类类型,而不必创建另一个虚拟对象比较类类型?
How can I compare two class type, without having to create another dummy object just to compare the class type?
推荐答案
尝试:
MyObject obj = new MyObject();
if(obj instanceof MyObject){System.out.println("true");} //true
由于继承,这对接口也是有效的:
Because of inheritance this is valid for interfaces, too:
class Animal {}
class Dog extends Animal {}
Dog obj = new Dog();
Animal animal = new Dog();
if(obj instanceof Animal){System.out.println("true");} //true
if(animal instanceof Animal){System.out.println("true");} //true
if(animal instanceof Dog){System.out.println("true");} //true
有关instanceof的进一步阅读: http://mindprod.com/jgloss/instanceof.html
For further reading on instanceof: http://mindprod.com/jgloss/instanceof.html
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