1.

import time, datetime


class Ly:
    def __init__(self, fun):
        self.fun = fun
        print('this is the first step on ' + str(datetime.datetime.now()))
        time.sleep(1)
        self.fun()

    def __call__(self):
        print('this is the thirty step on ' + str(datetime.datetime.now()))
        time.sleep(1)

@Ly
def show():
    print('this is the second step on ' + str(datetime.datetime.now()))
    time.sleep(1)

if __name__ == "__main__":
    show()
    print('this is the fourth step on ' + str(datetime.datetime.now()))

2.

import time


class Ly(object):

    def __init__(self, fun):
        print("this is the first step")
        time.sleep(1)
        self.fun = fun

    def __call__(self, *args):
        print("this is the second step")
        time.sleep(1)
        self.fun(*args)
        print("this is the fourth step")
        time.sleep(1)

@Ly
def show(a1, a2, a3, a4):
    print('this is the thirty step', a1, a2, a3, a4)
    time.sleep(1)


show("parm", "1", "1", "1")
print("After first part call")
time.sleep(1)
show("parm", "2", "2", "2")
print("After second part call")

從中可以發現:

(1).只要有被類裝飾器裝飾的物件，類裝飾器的 __init__ 函式就會執行（不需要呼叫）

(2).被類裝飾器裝飾的函式不論被呼叫幾次，__init__ 函式只會執行一次,並且它的執行是被裝飾函式宣告裝飾時就自動執行，不需要手動呼叫

(3).當被裝飾函式存在引數時，從 __call__ 函式傳進引數（不必須 *args,但這是一種規範 def __call__(self,*args,**kwargs))

     *args是指字串，**kwargs是指字典

3.

import time

class Ly:
    def __init__(self, one_parm, two_parm, three_parm):
        self.one_parm = one_parm
        self.two_parm = two_parm
        self.three_parm = three_parm

    def __call__(self, fun):
        print('性別為' + self.one_parm + "的" + self.two_parm + "歲的" + self.three_parm)
        time.sleep(1)
        def info(*args):
            fun(*args)

        return info


@Ly("男", "22", "ly")
def show(name, age, sex):
    print('性別為' + sex + "的" + age + "歲的" + name)


show("藍月", "20", "男")

注意:

(1).裝飾器有裝飾器的引數，函式（被裝飾器修飾的函式）有函式的引數，不可混淆

(2).的引數從 __init__ 函式中傳,函式的引數從 __call__ 函式中傳