接口中静态和默认方法的区别 [英] Difference Between static and default methods in interface

问题描述

当我注意到你现在可以在界面中定义静态和默认方法时，我正在通过接口学习。

I was learning through interfaces when I noticed that you can now define static and default methods in an interface.

public interface interfacesample2 {
    public static void method() {
        System.out.println("hello world");
    }

    public default void menthod3() {
        System.out.println("default print");
    }
}

请解释两者的区别以及是否有我们何时使用它的例子会很好。在接口上有点困惑。

Kindly explain the difference of the two and also if there's an example of when we would use this would be nice. A little confused on Interfaces.

推荐答案

Java 8中的静态和默认方法之间的差异：

Differences between static and default methods in Java 8:

1）默认方法可以覆盖实现类，而静态不能。

1) Default methods can be overriden in implementing class, while static cannot.

2）静态方法属于仅到Interface类，因此您只能在Interface类上调用静态方法，而不是在实现此接口的类上调用，请参阅：

2) Static method belongs only to Interface class, so you can only invoke static method on Interface class, not on class implementing this Interface, see:

public interface MyInterface {
    default void defaultMethod(){
        System.out.println("Default");
    }

    static void staticMethod(){
        System.out.println("Static");
    }    
}

public class MyClass implements MyInterface {

    public static void main(String[] args) {

        MyClass.staticMethod(); //not valid - static method may be invoked on containing interface class only
        MyInterface.staticMethod(); //valid
    }
}

3）类和接口可以有具有相同名称的静态方法，并且都不会覆盖其他方法！

3) Both class and interface can have static methods with same names, and neither overrides other!

public class MyClass implements MyInterface {

    public static void main(String[] args) {

        //both are valid and have different behaviour
        MyClass.staticMethod();
        MyInterface.staticMethod();
    }

    static void staticMethod(){
        System.out.println("another static..");
    }
}

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