Python 装饰器从入门到进阶

基础装饰器

装饰器本质上是一个函数，接收函数作为参数，返回增强后的函数。

def timer(func):

    import time

    def wrapper(*args, **kwargs):

        start = time.time()

        result = func(*args, **kwargs)

        print(f"{func.__name__} 耗时 {time.time() - start:.2f}s")

        return result

    return wrapper



@timer

def slow_function():

    import time

    time.sleep(1)

    return "done"



slow_function()

带参数的装饰器

def repeat(times):

    def decorator(func):

        def wrapper(*args, **kwargs):

            for _ in range(times):

                func(*args, **kwargs)

        return wrapper

    return decorator



@repeat(3)

def say_hello():

    print("Hello")

类装饰器

class CountCalls:

    def __init__(self, func):

        self.func = func

        self.count = 0

    def __call__(self, *args, **kwargs):

        self.count += 1

        print(f"调用次数: {self.count}")

        return self.func(*args, **kwargs)



@CountCalls

def test():

    pass

保留元信息

from functools import wraps



def decorator(func):

    @wraps(func)  # 保留 __name__ 和 __doc__

    def wrapper(*args, **kwargs):

        return func(*args, **kwargs)

    return wrapper

装饰器是 Python 优雅设计的典范，广泛应用于日志、权限、缓存等场景。