为什么我只能有一个 Calendar 对象实例
我只是想知道...
为什么我只能有一个 Calendar 对象的实例.有没有理由让它成为单身人士?
why can i have only one instance of Calendar object. Is there a reason for it to be a singleton?
我已尝试阅读 文档 但他们没有提到为什么需要这样做.快速谷歌搜索没有给我任何答案.
I have tried to read the documentation but they didn't mention why this is needed. And a quick google search didn't give me any answers.
推荐答案
Calendar 不是单例，它是一个抽象类.getInstance 方法是一个工厂方法，它返回 Calendar 类的具体实现.
Calendar is not a singleton, it is an abstract class. The getInstance method is a Factory method that returns a concrete implementation of the Calendar class.
在 Google 上搜索 java.util.Calendar 源代码，您将了解它是如何工作的.
Search Google for java.util.Calendar source code, and you will see how it works.
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