转换utf-16 - > utf-8并删除BOM

Question

我们有一个数据输入人员在Windows上以UTF-16编码,并希望拥有utf-8并删除BOM.utf-8转换有效但BOM仍然存在.我该如何删除？这就是我目前拥有的:

batch_3={'src':'/Users/jt/src','dest':'/Users/jt/dest/'}
batches=[batch_3]

for b in batches:
  s_files=os.listdir(b['src'])
  for file_name in s_files:
    ff_name = os.path.join(b['src'], file_name)  
    if (os.path.isfile(ff_name) and ff_name.endswith('.json')):
      print ff_name
      target_file_name=os.path.join(b['dest'], file_name)
      BLOCKSIZE = 1048576
      with codecs.open(ff_name, "r", "utf-16-le") as source_file:
        with codecs.open(target_file_name, "w+", "utf-8") as target_file:
          while True:
            contents = source_file.read(BLOCKSIZE)
            if not contents:
              break
            target_file.write(contents)

如果我hexdump -CI看到:

Wed Jan 11$ hexdump -C svy-m-317.json 
00000000  ef bb bf 7b 0d 0a 20 20  20 20 22 6e 61 6d 65 22  |...{..    "name"|
00000010  3a 22 53 61 76 6f 72 79  20 4d 61 6c 69 62 75 2d  |:"Savory Malibu-|

在结果文件中.如何删除BOM？

谢谢

Answer 1

这之间的区别UTF-16LE和UTF-16

• UTF-16LE是没有 BOM的小端
• UTF-16带有 BOM的大端或小端

因此,当您使用时UTF-16LE,BOM只是文本的一部分.请UTF-16改用,以便自动删除BOM.原因UTF-16LE和UTF-16BE存在是因为人们可以随身携带"正确编码"的文本而无需BOM,这不适用于您.

注意使用一种编码进行编码并使用另一种编码进行解码时会发生什么 (有时会UTF-16自动检测UTF-16LE,而不是总是.)

>>> u'Hello, world'.encode('UTF-16LE')
'H\x00e\x00l\x00l\x00o\x00,\x00 \x00w\x00o\x00r\x00l\x00d\x00'
>>> u'Hello, world'.encode('UTF-16')
'\xff\xfeH\x00e\x00l\x00l\x00o\x00,\x00 \x00w\x00o\x00r\x00l\x00d\x00'
 ^^^^^^^^ (BOM)

>>> u'Hello, world'.encode('UTF-16LE').decode('UTF-16')
u'Hello, world'
>>> u'Hello, world'.encode('UTF-16').decode('UTF-16LE')
u'\ufeffHello, world'
    ^^^^ (BOM)

或者你可以在shell上做到这一点:

for x in * ; do iconv -f UTF-16 -t UTF-8 <"$x" | dos2unix >"$x.tmp" && mv "$x.tmp" "$x"; done

Answer 2

只需使用str.decode和str.encode:

with open(ff_name, 'rb') as source_file:
  with open(target_file_name, 'w+b') as dest_file:
    contents = source_file.read()
    dest_file.write(contents.decode('utf-16').encode('utf-8'))

str.decode 将为您摆脱BOM(并推断出字节顺序).