python 文件的md5

参考http://blog.csdn.net/csapr1987/article/details/7633239

简单模式

from hashlib import md5
 
def md5_file(name):
    m = md5()
    a_file = open(name, 'rb')    #需要使用二进制格式读取文件内容
    m.update(a_file.read())
    a_file.close()
    return m.hexdigest()
 
if __main__ == '__init__':
    print md5_file('d:/test.txt')

大文件速度更快一点的方式

#!/usr/bin/python
#encoding=utf-8
import io
import sys
import hashlib
import string

def printUsage():
	print ('''Usage: [python] pymd5sum.py ''')
	
def main():
	if(sys.argv.__len__()==2):
		#print(sys.argv[1])

		m = hashlib.md5()
		file = io.FileIO(sys.argv[1],'r')
		bytes = file.read(1024)
		while(bytes != b''):
			m.update(bytes)
			bytes = file.read(1024) 
		file.close()
		
		#md5value = ""
		md5value = m.hexdigest()
		print(md5value+"\t"+sys.argv[1])
		
		#dest = io.FileIO(sys.argv[1]+".CHECKSUM.md5",'w')
		#dest.write(md5value)
		#dest.close()
	
	else:
		printUsage() 
main()