參考網址
　　> http://www.cnblogs.com/rhcad/archive/2011/12/21/2295507.html
　　> http://www.cnblogs.com/huxi/archive/2011/03/01/1967600.html

簡述

- 裝飾器的特點就是對已有的對象添加額外功能，且不修改對象內部代碼
- 使用裝飾器語法糖(＠XXXXX)裝飾后，相當于嵌套閉合函數語法糖指向的函數也就是一個高階函數，
   被裝飾函數就是傳入的函數實參

一：不帶參數

  #!/usr/bin/python
  # -*- coding:utf-8 -*-

# 16 Oct. 2015
# Author:  Huang Junkai

import time

def time_calu1(func):
 def _extra():
     start = time.clock()
     func()
     end = time.clock()
     print 'total time:', end - start
 return _extra

 def time_calu2(func):
 start = time.clock()
 func()
 end = time.clock()
 print 'total time:', end - start
 return func

 @time_calu2
 def func():
 print 'Wow! Success'

 func()
 func()

看看兩個裝飾器time_calu1與time_calu2的區別：

前者是一次性的，只對第一個func()有效，即28~19行代碼等效于func = time_calu1(func); func() 
而后者可保證對每次調用的func()，都有效

二：帶參數

代碼：
#!/usr/bin/python
-- coding:utf-8 --

 # 16 Oct. 2015
 # Author:  Huang Junkai
 
 import time

 def time_calu1(func):
     def _extra(a, b):
         start = time.clock()
     result = func(a, b)
     end = time.clock()
     print 'used:', end - start
     return result
 return _extra


 def time_calu2(func):
 start = time.clock()
 func()
 end = time.clock()
 print 'used:', end - start
 return func



 @time_calu1
 def foo(a, b):
 # print 'Wow! Success: the result is %s' % (a + b)
 return a + b

 result = foo(1, 2)
 print result