如何检查对象是否实现了接口？

How to check if some class implements interface? When having:

如何检查某些类是否实现了接口？当有：

Character.Gorgon gor = new Character.Gorgon();

Character.Gorgon gor = new Character.Gorgon（）;

how to check if gor implements Monster interface?

如何检查gor是否实现了Monster接口？

public interface Monster {

    public int getLevel();

    public int level = 1;
}

public class Character {
    public static class Gorgon extends Character implements Monster {
        public int level;
        @Override
        public int getLevel() { return level; }

        public Gorgon() {
            type = "Gorgon";
        }
    }
}

Is the method getLevel() overridden in Gorgon correctly, so it can return level of new gor created?

方法getLevel（）是否正确地在Gorgon中重写，因此它可以返回创建的新gor的级别？

4 个解决方案

#1

180

For an instance

例如

Character.Gorgon gor = new Character.Gorgon();

Then do

然后做

gor instanceof Monster

For a Class instance do

对于Class实例

Class<?> clazz = Character.Gorgon.class;
Monster.class.isAssignableFrom(clazz);

#2

Use

使用

if (gor instanceof Monster) {
    //...
}

#3

In general for AnInterface and anInstance of any class:

通常用于任何类的AnInterface和anInstance：

AnInterface.class.isAssignableFrom(anInstance.getClass());

#4

If you want a method like public void doSomething([Object implements Serializable]) you can just type it like this public void doSomething(Serializable serializableObject). You can now pass it any object that implements Serializable but using the serializableObject you only have access to the methods implemented in the object from the Serializable interface.

如果你想要一个像public void doSomething（[Object implements Serializable]）这样的方法，你可以像这个public void doSomething（Serializable serializableObject）一样输入它。您现在可以将任何实现Serializable的对象传递给它，但是使用serializableObject只能访问Serializable接口中对象中实现的方法。

#1

180