string.go
func StringMD5Hex(data string) string {
	hash := md5.New()
	hash.Write([]byte(data))
	return fmt.Sprintf("%x", hash.Sum(nil))
}
func StringMD5Hex(data string) string {
	hash := md5.New()
	hash.Write([]byte(data))
	return fmt.Sprintf("%x", hash.Sum(nil))
}
// StringMD5Hex returns the hex encoded MD5 hash of data