Python 装饰器深度解析：原理与应用场景

Python 装饰器深度解析：原理与应用场景

装饰器是 Python 的高级特性，允许在不修改原函数的情况下扩展功能。

1. 基础装饰器

import time



def timer(func):

    def wrapper(*args, **kwargs):

        start = time.time()

        result = func(*args, **kwargs)

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

        return result

    return wrapper



@timer

def slow_function():

    time.sleep(1)

    return "done"

2. 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")

3. 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"Called {self.count} times")

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

4. 保留元信息（functools.wraps）

from functools import wraps



def decorator(func):

    @wraps(func)

    def wrapper(*args, **kwargs):

        return func(*args, **kwargs)

    return wrapper

装饰器广泛应用于日志、权限控制、缓存等场景。