python 读取二进制文件 转为16进制输出

示例：

#!/usr/bin/env python
#encoding: utf-8
import binascii
fh = open(r'C:\Temp\img\2012517165556.png', 'rb')
a = fh.read()
#print 'raw: ',`a`,type(a)
hexstr = binascii.b2a_hex(a)
print a
print hexstr #示意结果为4d5a900003000000....