hex函数，参数可以是一个int整数或一个bytes类型元素，转为0x的十六进制字符串形式
with open(file='J:/新建文本文档.txt', mode='rb') as f:
s = f.read()
print(type(s), s)
result = ''
for i in s:
result += hex(i)
print(result)
<class 'bytes'> b'1abc\xe6\x97\xb6\xe9\x97\xb4'
0x310x610x620x630xe60x970xb60xe90x970xb4