理解Python中的装饰器

@decoratordef foo():    pass

def log(func):    def wrapper(*args, **kwargs):        print(f"calling {func.__name__} with args={args}, kwargs={kwargs}")        return func(*args, **kwargs)    return wrapper@logdef add(x, y):    return x + yadd(1, 2)  # 输出 calling add with args=(1, 2), kwargs={}           # 输出 3

def authenticate(func):    def wrapper(*args, **kwargs):        if authenticated:            return func(*args, **kwargs)        else:            raise Exception("未授权")            return wrapper@authenticatedef get_secret_data():    pass

cache = {}def memoize(func):    def wrapper(*args):        if args in cache:            return cache[args]        else:            result = func(*args)            cache[args] = result            return result            return wrapper@memoizedef fib(n):    if n <p>四、常见的装饰器模式</p><p>装饰器模式是一种常见的设计模式，它包括以下几个元素：</p><ol><li>一个抽象组件类，定义了被装饰对象的接口。</li><li>一个具体组件类，实现了抽象组件类定义的接口。</li><li>一个抽象装饰器类，定义了装饰器对象的接口。</li><li>一个具体装饰器类，实现了抽象装饰器类定义的接口。</li></ol><p>在Python中，我们通常使用函数来模拟装饰器模式中的类和对象。下面是一个简单的例子。</p><pre class="brush:python;toolbar:false;">class Component:    def operation(self):        passclass ConcreteComponent(Component):    def operation(self):        return "具体组件的操作"class Decorator(Component):    def __init__(self, component):        self._component = component            def operation(self):        return self._component.operation()class ConcreteDecoratorA(Decorator):    def added_behavior(self):        return "具体装饰器A的操作"        def operation(self):        return f"{self.added_behavior()}，然后{self._component.operation()}"class ConcreteDecoratorB(Decorator):    def added_behavior(self):        return "具体装饰器B的操作"        def operation(self):        return f"{self.added_behavior()}，然后{self._component.operation()}"component = ConcreteComponent()decoratorA = ConcreteDecoratorA(component)decoratorB = ConcreteDecoratorB(decoratorA)print(decoratorB.operation())  # 输出 具体装饰器B的操作，然后具体装饰器A的操作，然后具体组件的操作