python 装饰器

一、无参数，无返回值的装饰器

 1 def check(func):
 2     def inner():
 3         print('def')
 4         func()
 5     return inner
 6 
 7 @check    #foo = check(foo)
 8 def foo():
 9     print('abc')
10    
11 foo()

二、2个装饰器

 1 # -*- coding:utf-8 -*-
 2 
 3 def check(func):
 4     def inner():
 5         print('def')
 6         func()
 7     return inner
 8 
 9 def check1(func):
10     def inner():
11         print('ghk')
12         func()
13     return inner
14 
15 @check    #foo = check(foo)   后装饰，先执行
16 @check1   #foo = check1(foo)  先装饰，后执行
17 def foo():
18     print('abc')
19 
20 foo()

结果：

1 def
2 ghk
3 abc

三、带参数，无返回值函数的装饰器

 1 # -*- coding:utf-8 -*-
 2 
 3 def check(func):
 4     def inner(arg):
 5         print('def')
 6         func(arg)
 7     return inner
 8 
 9 @check    #foo = check(foo)
10 def foo(arg):
11     print('abc%s' % arg)
12 
13 foo('d')

四、带参数，带返回值函数的装饰器

 1 # -*- coding:utf-8 -*-
 2 
 3 def check(func):
 4     def inner(arg):
 5         print('def')
 6         ret = func(arg)
 7         print('ghk')
 8         return ret
 9     return inner
10 
11 @check    #foo = check(foo)
12 def foo(arg):
13     print('abc%s' % arg)
14     return 'ok'
15 
16 ret = foo('d')
17 print(ret)

五、通用的装饰器

 1 # -*- coding:utf-8 -*-
 2 
 3 def check(func):
 4     def inner(*args, **kwargs):
 5         print('...')
 6         ret = func(*args, **kwargs)
 7         print('---')
 8         return ret
 9     return inner
10 
11 @check    #foo = check(foo)
12 def foo(arg):
13     print('abc%s' % arg)
14     return 'ok'
15 
16 ret = foo('d')
17 print(ret)

六、装饰器带参数

 1 # -*- coding:utf-8 -*-
 2 
 3 def outter(arg):
 4     def check(func):
 5         def inner(*args, **kwargs):
 6             print(arg)
 7             print('...')
 8             ret = func(*args, **kwargs)
 9             print('---')
10             return ret
11         return inner
12     return check
13 
14 @outter('e')    #先执行outter('e')，再装饰foo = check(foo)
15 def foo(arg):
16     print('abc%s' % arg)
17     return 'ok'
18 
19 ret = foo('d')
20 print(ret)

结果：

1 e
2 ...
3 abcd
4 ---
5 ok