解决python2.x文件读写编码问题

#coding=utf-8
# test.txt是一个以gbk2312编码（简体中文windows系统中的默认文本编码）的文本文件
# 文本写入
with open('test.txt', 'a') as f:
  f.write('test') # 正常写入
  f.write('测试') # 正常写入,乱码
  f.write（u’测试') # 写入错误，触发UnicodeEncodeError异常
# 文本读取
with open('test.txt') as f:
  for line in f:
    print line, type(line)  # 输出test娴嬭瘯, <type 'str'>

# 解决方法1
with open('test.txt', 'w') as f:
  f.write('测试'.decode('utf-8').encode('gb2312'))
  f.write(u'测试‘.ecode('gb2312')