Python使用hashlib模块进行文件MD5校验的实现方法

#python 检测文件MD5值
#python version 2.6
import hashlib
import os,sys
#简单的测试一个字符串的MD5值
def GetStrMd5(src):
  m0=hashlib.md5()
  m0.update(src)
  print m0.hexdigest()
  pass
#大文件的MD5值
def GetFileMd5(filename):
  if not os.path.isfile(filename):
    return
  myhash = hashlib.md5()
  f = file(filename,'rb')
  while True:
    b = f.read(8096)
    if not b :
      break
    myhash.update(b)
  f.close()
  return myhash.hexdigest()
def CalcSha1(filepath):
  with open(filepath,'rb') as f:
    sha1obj = hashlib.sha1()
    sha1obj.update(f.read())
    hash = sha1obj.hexdigest()
    print(hash)
    return hash
def CalcMD5(filepath):
  with open(filepath,'rb') as f:
    md5obj = hashlib.md5()
    md5obj.update(f.read())
    hash = md5obj.hexdigest()
    print(hash)
    return hash
if __name__ == "__main__":
  if len(sys.argv)==2 :
    hashfile = sys.argv[1]
    if not os.path.exists(hashfile):
      hashfile = os.path.join(os.path.dirname(__file__),hashfile)
      if not os.path.exists(hashfile):
        print("cannot found file")
      else
        CalcMD5(hashfile)
    else:
      CalcMD5(hashfile)
      #raw_input("pause")
  else:
    print("no filename")