Python的unicode函数似乎和sys.getdefaultencoding()有关。附： 《sys.setdefaultencoding is evil》http://ziade.org/2008/01/08/syssetdefaultencoding-is-evil/

test unicode and default coding

# -*- coding: utf-8 -*-

a = '啦啦啦'

# an error will happen here
print '##### 1 #####'
try:
    print unicode(a)
except Exception as e:
    print 'error:'
    print e

# explicit encoding
print '##### 2 #####'
a = '啦啦啦'
print unicode(a,'utf-8')

# time.strftime2
print '##### 3 #####'
import time
now = time.localtime()
timestr = time.strftime('%m月%d日',now)
print timestr
try:
    print unicode(timestr)
except Exception as e:
    print 'error:'
    print e

print '##### 4 #####'
try:
    timestr = time.strftime(u'%m月%d日',now)
except Exception as e:
    print 'error:'
    print e

# set default encoding
import sys
print sys.getdefaultencoding()
reload(sys)
sys.setdefaultencoding('utf-8')

# everything ok.
print '##### 5 #####'
a = '啦啦啦'
print unicode(a)

print '##### 6 #####'
timestr = time.strftime('%m月%d日',now)
print timestr
print unicode(timestr)

print '##### 7 #####'
timestr = time.strftime(u'%m月%d日',now)
print timestr

got it
果然没这么用过