python文件取MD5

import hashlib

def md5sum(filename, blocksize=65536):
hash = hashlib.md5()
with open(filename, "rb") as f:
#必须是rb形式打开的，否则的两次出来的结果不一致
for block in iter(lambda: f.read(blocksize), b""):
hash.update(block)
return hash.hexdigest()