在Java中，when是枚举常量的构造函数是否被调用？ [英] In Java, when is the constructor for an enumerated constant invoked?

问题描述

要在Java中使用一个设计的例子，下面是代码：

To use a contrived example in Java, here's the code:

enum Commands{
   Save("S");
   File("F");

   private String shortCut;
   private Commands(String shortCut){ this.shortCut = shortCut; }
   public String getShortCut(){ return shortCut; }
}

我有以下测试/驱动程序代码：

I have the following test/driver code:

public static void main(String args[]){
   System.out.println(Commands.Save.getShortCut());
}

问题是：
在Java中，when是构造函数一个枚举常量调用？在上面的例子中，我只使用 Save 枚举常量。这是否意味着构造函数只被调用一次以创建 Save ？或者保存和文件可以一起构造吗？

The question is: In Java, when is the constructor for an enumerated constant invoked? In the above example, I am only using the Save enumerated constant. Does this mean that the constructor is called once to create Save only? Or will both Save and File be constructed together regardless?

推荐答案

当 enum 类初始化时，调用构造函数。每个构造函数将在成员声明顺序中被调用，而不管实际引用和使用了哪些成员。

The constructors are invoked when the enum class is initialized. Each constructor will be invoked, in member declaration order, regardless of which members are actually referenced and used.

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