本文是小编为大家收集整理的关于Java中的Singleton模式和静态类的区别是什么？的处理/解决方法，可以参考本文帮助大家快速定位并解决问题，中文翻译不准确的可切换到English标签页查看源文。
问题描述
单身人士与仅装有静态字段的课程有何不同?
推荐答案
几乎每次写静态类时，我都希望我将其作为非静态类实现.考虑:
- 可以扩展非静态类.多态性可以节省很多重复.
- 非静态类可以实现接口，当您想将实现与API分开时，该接口可能会派上用场.
由于这两个点，非静态类使得可以为依赖于它们的项目编写更可靠的单元测试.
但是，单身模式距离静态类仅半步.您的有点获得这些好处，但是如果您通过" className.Incance"直接在其他类中访问它们，则您将创建访问这些好处的障碍.就像PH0ENIX指出的那样，使用依赖注入模式，您会更好.这样，可以告诉一个特定类是(或不是)单身人士的di框架.您将获得嘲笑，单位测试，多态性和更加灵活性的所有好处.
其他推荐答案
让我总结一下:)
本质上的区别是:单例的存在形式是一个对象，静态不是.这揭示了以下内容:
- 可以扩展单身人士.静态不.
- 单例创建如果未正确实现，则可能不会是线程安全.静态不.
- 单身人士可以作为对象传递.静态不.
- 单身人士可以收集垃圾.静态不.
- 单身人比静态类好！
- 更多这里，但我还没有意识到:)
最后但并非最不重要的一点是，每当您要实施单身人士时，请考虑重新设计您的想法不使用这个神对象(相信我，您倾向于将所有"有趣"的东西放入此类中)并使用一个名为"上下文"或类似的普通类.
其他推荐答案
可以懒洋洋地初始化单身人士.
问题描述
How is a singleton different from a class filled with only static fields?
推荐答案
Almost every time I write a static class, I end up wishing I had implemented it as a non-static class. Consider:
- A non-static class can be extended. Polymorphism can save a lot of repetition.
- A non-static class can implement an interface, which can come in handy when you want to separate implementation from API.
Because of these two points, non-static classes make it possible to write more reliable unit tests for items that depend on them, among other things.
A singleton pattern is only a half-step away from static classes, however. You sort of get these benefits, but if you are accessing them directly within other classes via `ClassName.Instance', you're creating an obstacle to accessing these benefits. Like ph0enix pointed out, you're much better off using a dependency injection pattern. That way, a DI framework can be told that a particular class is (or is not) a singleton. You get all the benefits of mocking, unit testing, polymorphism, and a lot more flexibility.
其他推荐答案
Let's me sum up :)
The essential difference is: The existence form of a singleton is an object, static is not. This conduced the following things:
- Singleton can be extended. Static not.
- Singleton creation may not be threadsafe if it isn't implemented properly. Static not.
- Singleton can be passed around as an object. Static not.
- Singleton can be garbage collected. Static not.
- Singleton is better than static class!
- More here but I haven't realized yet :)
Last but not least, whenever you are going to implement a singleton, please consider to redesign your idea for not using this God object (believe me, you will tend to put all the "interesting" stuffs to this class) and use a normal class named "Context" or something like that instead.
其他推荐答案
A singleton can be initialized lazily, for one.
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