python 裝飾器詳解
裝飾器
裝飾器其實就是一個閉包，把一個函數當做參數然後返回一個替代版函數
裝飾器有２個特性：
一是可以把被裝飾的函數替換成其他函數，
二是可以在加載模塊時候立即執行
def w1(func):
def inner():
# 驗證1
# 驗證2
# 驗證3
func()
return inner
@w1
def f1():
print(‘f1‘)
裝飾器(decorator)功能
1. 引??誌
2. 函數執?時間統計
3. 執?函數前預備處理
4. 執?函數後清理功能
5. 權限校驗等場景
6. 緩存
上代碼直觀感受
#定義函數： 完成包裹數據
def makeBold(fn):
def wrapped():
return "<b>" + fn() + "</b>"
return wrapped
@makeBold
def test1():
return "hello world-1"
#定義函數： 完成包裹數據
def makeItalic(fn):
def wrapped():
return "<i>" + fn() + "</i>"
return wrapped
@makeItalicdef test2():
return "hello world-2"
@makeBold
@makeItalic
def test3():
return "hello world-3"
print(test1())
print(test2())
print(test3())
裝飾器對無參函數進行裝飾
from time import ctime, sleep
def timefun(func):
def wrappedfunc():
print("%s called at %s"%(func.__name__, ctime()))
func()
return wrappedfunc@timefun
def foo():
print("I am foo")
foo()
sleep(2)
foo()
裝飾器對有參函數進行裝飾
from time import ctime, sleep
def timefun(func):
def wrappedfunc(a, b):
print("%s called at %s"%(func.__name__, ctime()))
print(a, b)
func(a, b)
return wrappedfunc
@timefun
def foo(a, b):
print(a+b)
foo(3,5)
sleep(2)
foo(2,4)
裝飾器對不定長參數函數進行裝飾
from time import ctime, sleep
def timefun(func):
def wrappedfunc(*args, **kwargs):
print("%s called at %s"%(func.__name__, ctime()))
func(*args, **kwargs)
return wrappedfunc
@timefun
def foo(a, b, c):
print(a+b+c)
foo(3,5，7）
sleep(2)
foo(2,4，9)
裝飾器對帶有返回值的函數進行裝飾
from time import ctime, sleep
def timefun(func):
def wrappedfunc(*args, **kwargs):
print("%s called at %s"%(func.__name__, ctime()))
ret = func()
return ret
return wrappedfunc
@timefun
def foo():
print("I am foo")
@timefun
def getInfo():
return ‘----hahah---‘
帶有參數的裝飾器
from time import ctime, sleep
def timefun_arg(pre="hello"):
def timefun(func):
def wrappedfunc():
print("%s called at %s %s"%(func.__name__, ctime(), pre))
return func()
return wrappedfunc
return timefun
@timefun_arg(“sxt")
def foo():
print("I am foo")
@timefun_arg("python")
def too():
print("I am too" )
from time import ctime, sleep def timefun(func): def wrappedfunc(*args, **kwargs): print("%s called at %s"%(func.__name__, ctime())) func(*args, **kwargs) return wrappedfunc @timefun def foo(a, b, c): print(a+b+c) foo(3,5,7) sleep(2) foo(2,4,9)
python 裝飾器詳解