编辑“︁工厂模式”︁（章节）

=== 2. 工厂方法模式 ===
将工厂抽象为接口，每个具体产品由对应的子工厂创建，符合[[开闭原则]]。

==== 类图 ====
<mermaid>
classDiagram
    interface Animal {
        <<interface>>
        +speak()
    }
    class Dog
    class Cat
    Animal <|-- Dog
    Animal <|-- Cat

    interface AnimalFactory {
        <<interface>>
        +createAnimal() Animal
    }
    class DogFactory
    class CatFactory
    AnimalFactory <|-- DogFactory
    AnimalFactory <|-- CatFactory

    DogFactory --> Dog
    CatFactory --> Cat
</mermaid>

==== 代码示例 ====
<syntaxhighlight lang="python">
from abc import ABC, abstractmethod

# 产品接口
class Button(ABC):
    @abstractmethod
    def render(self): pass

# 具体产品
class WindowsButton(Button):
    def render(self): return "Windows风格按钮"

class MacOSButton(Button):
    def render(self): return "MacOS风格按钮"

# 工厂接口
class GUIFactory(ABC):
    @abstractmethod
    def create_button(self) -> Button: pass

# 具体工厂
class WindowsFactory(GUIFactory):
    def create_button(self): return WindowsButton()

class MacOSFactory(GUIFactory):
    def create_button(self): return MacOSButton()

# 客户端
def client_code(factory: GUIFactory):
    button = factory.create_button()
    print(button.render())

client_code(WindowsFactory())  # 输出: Windows风格按钮
</syntaxhighlight>