http://www.cnblogs.com/huxi/archive/2010/12/05/1897271.html
在没有reload(sys)之前调用sys.setdefaultencoding("utf-8")出错
>>> import sys
>>> sys.getdefaultencoding()
'ascii'
>>>
>>> sys.setdefaultencoding("utf-8")
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
AttributeError: 'module' object has no attribute 'setdefaultencoding'
>>>
>>> reload(sys)
<module 'sys' (built-in)>
>>> sys.setdefaultencoding("utf-8")