在 Java 中使用 Enum 作为单例的最佳方法是什么? [英] What is the best approach for using an Enum as a singleton in Java?

问题描述

建立在 SO 问题 Java 中的最佳单例实现 -即关于使用枚举创建单例 - 之间有什么区别/优点/缺点(省略构造函数)

Building on what has been written in SO question Best Singleton Implementation In Java - namely about using an enum to create a singleton - what are the differences/pros/cons between (constructor omitted)

public enum Elvis {
    INSTANCE;
    private int age;

    public int getAge() {
        return age;
    }
}

然后调用Elvis.INSTANCE.getAge()

和

public enum Elvis {
    INSTANCE;
    private int age;

    public static int getAge() {
        return INSTANCE.age;
    }
}

然后调用Elvis.getAge()

推荐答案

假设您要绑定的东西将使用它所给定的任何对象的属性 - 您可以很容易地传递 Elvis.INSTANCE，但不能传递Elvis.class 并期望它找到属性(除非故意编码以查找类的静态属性).

Suppose you're binding to something which will use the properties of any object it's given - you can pass Elvis.INSTANCE very easily, but you can't pass Elvis.class and expect it to find the property (unless it's deliberately coded to find static properties of classes).

基本上，当您想要一个实例时，您只使用单例模式.如果静态方法对你来说没问题，那么就使用它们，不要打扰枚举.

Basically you only use the singleton pattern when you want an instance. If static methods work okay for you, then just use those and don't bother with the enum.

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