字符串转换成16进制数据，当网络编程时，经常需要把字符1（0x31）转换成hex的1（0x1），例如：mac地址-String into hexadecimal data, when network programming, we often need to transfer the character 1 (0x31) to convert hex to 1 (0x1), for example: mac address

获取linux下客户机的MAC地址获取linux下客户机的MAC地址-Access to the client s MAC address under Linux