Python：decorator装饰器的使用示例

def decorator(func):
    def wrapper(*arg, **kwargs):
        print("before")
        ret = func(*arg, **kwargs)
        print("after")
        return ret
    return wrapper

# -*- coding: utf-8 -*-
# 作用于普通方法
@decorator
def foo(name):
    print('my name is:', name)
class Foo(object):
    # 作用于实例方法
    @decorator
    def foo(self, name):
        print('my name is:', name)
    # 作用于类方法
    @classmethod
    @decorator
    def class_foo(cls, name):
        print('my name is:', name)
    # 作用于静态方法
    @staticmethod
    @decorator
    def static_foo(name):
        print('my name is:', name)
if __name__ == '__main__':
    foo('Tom')
    Foo().foo('Tom')
    Foo.class_foo('Tom')
    Foo.static_foo('Tom')
"""
4中方式都可以正常执行，输入如下
before
my name is: Tom
after
"""

def decorator(func):
    def wrapper(name):
        print("before")
        # ret = func(*arg, **kwargs)
        # 取消原来的不定参数，写为固定参数
        ret = func(name)
        print("after")
        return ret
    return wrapper

# 普通函数可以正常执行
foo('Tom')
# 静态方法可以正常执行
Foo.static_foo('Tom')
# 实例方法报错
Foo().foo('Tom')
# TypeError: wrapper() takes 1 positional argument but 2 were given
# 类方法报错
Foo.class_foo('Tom')
# TypeError: wrapper() takes 1 positional argument but 2 were given