数据类型转换
string to other = 字符串转其他
string -> int
i1, err := strconv.Atoi("1")
string -> int64
i64, err := strconv.ParseInt("2", 10, 64)
hexstring -> []byte 16进制字符串转(16进制代表的)byte数组
hex_str := "4161"
hex_data, _ := hex.DecodeString(hex_str)
fmt.Println(string(hexData))//Aa