java 使这个私有枚举静态与否？
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Make this private enum static or not?
提问by helpermethod
In a class, I need to define different actions which are passed into a method. Now, all instances can safely share these action, so I thought I could safely make the enum static.
在一个类中，我需要定义传递给方法的不同动作。现在，所有实例都可以安全地共享这些操作，所以我想我可以安全地将枚举设为静态。
But in almost all examples I've seen, the nested enum is never made static. So, which is the preferred way to define a nested (private) enum? Does it actually make sense to not make it static?
但在我见过的几乎所有示例中，嵌套枚举从未被设为静态。那么，哪个是定义嵌套（私有）枚举的首选方法？不让它静态真的有意义吗？
public class MyClass {
private static enum Action {
READ("read"),
WRITE("write");
final String value;
Action(String value) {
this.value = value;
}
String getValue() {
return value;
}
}
// attributes, methods, constructors and so on
}
回答by Jon Skeet
The Java Language Specification, section 8.9, states:
在Java语言规范，8.9节，规定：
Nested enum types are implicitly static. It is permissable to explicitly declare a nested enum type to be static.
嵌套的枚举类型是隐式静态的。允许将嵌套枚举类型显式声明为静态。
So you can, but you don't have to, and it'll make no difference. Personally I don't think I'd bother, as it's implicit anyway.
所以你可以，但你没有必要，这不会有什么区别。就我个人而言，我认为我不会打扰，因为无论如何它都是隐含的。
回答by Miserable Variable
Nested enum types are implicitly static :)
嵌套的枚举类型是隐式静态的 :)
回答by Kal
If an enum is a member of a class, it is implicitly static
如果枚举是类的成员，则它是隐式静态的
回答by Danail Tsvetanov
As enum is inherently static, there is no need and makes no difference when using static-keyword in enum.
由于 enum 本质上是静态的，因此在 enum 中使用 static-keyword 时没有必要并且没有任何区别。
