装饰器之类装饰器

一、类中的方法实现装饰器

　　类当中的方法和普通方法一样，使用方法一样，只有对象进行调用的时候，第一个参数会默认吧对象实例传入，然后隐匿

　　这个相当于__call__和__new__一类的东西吧

def godme(fun):
    def __godme(self,message):
        print('before')
        fun(self,message)
        print('after')
    return __godme
 
class Person:
    def show(self,message):
        print(message)
    @godme
    def say(self,message):
        print(message)
 
person = Person()
person.say('happy')


打印结果：
'''
before
happy
after
"

二、类上实现装饰器1

def godme(fun):
    def __godme(cls,*args,**kwargs):
        print('before')
        fun(cls,*args,**kwargs)
        print('after')
    return __godme


@godme
class Person:
    def __new__(cls, *args, **kwargs):
        print('__new__')
 


打印结果：

before
__new__
after

三、类上实现装饰器2

class tracer(object):
    def __init__(self, func):
        self.calls = 0
        self.func = func

    def __call__(self, *args, **kwargs):
        self.calls += 1
        print("call %s to %s" % (self.calls, self.func.__name__))
        self.func(*args, **kwargs)


@tracer
def spam(a, b, c):
    print(a, b, c)


if __name__ == '__main__':
    spam(1, 2, 3)
    spam("a", "b", "c")
    spam(4, 5, 6)


打印结果：
call 1 to spam
1 2 3
call 2 to spam
a b c
call 3 to spam
4 5 6