使用场景

def decorator(func):
    def wrapper(*args, **kwargs):
        print("start ---")
        func(*args, **kwargs)
        print("--- end")
    return wrapper

def greeting():
    print('Hello')

greeting = decorator(greeting)
greeting()

# 输出
start ---
Hello
--- end

装饰器 ' @ ' 使用

def decorator(func):
    def wrapper(*args, **kwargs):
        print("start ---")
        func(*args, **kwargs)
        print("--- end")
    return wrapper

@decorator
def greeting():
    print('Hello')

greeting()

# 输出
start ---
Hello
--- end

带参数装饰器

def decorator(user):
    def wrapper1(func):
        def wrapper2(*args, **kwargs):
            print("start ---")
            func(*args, **kwargs)
            print(user)
            print("--- end")
        return wrapper2
    return wrapper1

@decorator(user="Jack")
def greeting():
    print('Hello')

greeting()

# 输出
start ---
Hello
Jack
--- end

装饰器类

class decorator(object):
    def __init__(self, user='Jack'):
        self.user = user

    def __call__(self, func):
        def wrapper(*args, **kwargs):
            print("start ---")
            func(*args)
            print(self.user)
            print("--- end")
            return func
        return wrapper

@decorator(user="Jack")
def greeting():
    print('Hello')

greeting()

# 输出
start ---
Hello
Jack
--- end