有人能解释一下工厂模式和战略模式之间的区别吗?

对于我来说,两者看起来是一样的,除了一个额外的工厂类(在工厂模式中创建一个product对象)


当前回答

根据奥斯卡的说法和他的准则:

getCommand是工厂类,UnixCommand、WindowsCommand和OSXCommand类是策略类

其他回答

只是补充一下tvanfosson所说的,就实现而言,很多模式看起来都是一样的。也就是说,很多时候你创建了一个接口,而在你的代码中可能没有,然后创建了该接口的一堆实现。区别在于它们的目的和使用方式。

First of all a difference between simple factory and abstract factory must be made. The first one is a simple factory where you only have one class which acts as a factory for object creation, while in the latter you connect to an factory interface (which defines the method names) and then call the different factories that implement this interface which are supposed to have different implementations of the same method based on some criteria. For example, we have a ButtonCreationFactory interface, which is implemented by two factories, the first WindowsButtonCreationFactory (creates buttons with Windows look and feel) and the second LinuxButtonCreationFactory (creates buttons with Linux look and feel). So both these factories do have the same creation method with different implementations (algorithms). You can reference this in runtime based on the method that you type of button that you want.

例如,如果你想要带有Linux外观和感觉的按钮:

ButtonCreationFactory myFactory = new LinuxButtonCreationFactory();
Button button1 = myFactory.createButton(...);

或者你想要Windows按钮

ButtonCreationFactory myFactory = new WindowsButtonCreationFactory();
Button button1 = myFactory.createButton(...);

Exactly in this case, it results in a kind of strategy pattern, since it differentiates algorithms for doing some creation. However, it differs from it semantically because it is used for OBJECT CREATION rather than operational algorithms. So, basically with abstract factory you have object creation using different strategies, which makes it very similar to the strategy pattern. However the AbstractFactory is creational, while the Strategy pattern is operational. Implementation wise, they result to be the same.

简而言之:

工厂是用于创建具有相同行为的多个对象,而策略是用于具有不同工作方式的一个对象。

根据奥斯卡的说法和他的准则:

getCommand是工厂类,UnixCommand、WindowsCommand和OSXCommand类是策略类

策略模式允许您多态地更改类的行为。

工厂模式允许封装对象创建。

加里说得很好。如果您使用的编码原则是抽象的,而不是“具体化”的,那么很多模式看起来就像是主题的变体。