java如何给单片机串口发送一个16进制的命令

public static byte[] hex2byte(String hex) {
String digital = "0123456789ABCDEF";
String hex1 = hex.replace(" ", "");
char[] hex2char = hex1.toCharArray();
byte[] bytes = new byte[hex1.length() / 2];
byte temp;
for (int p = 0; p < bytes.length; p++) {
temp = (byte) (digital.indexOf(hex2char[2 * p]) * 16);
temp += digital.indexOf(hex2char[2 * p + 1]);
bytes[p] = (byte) (temp & 0xff);
}
return bytes;
}

byte [] asd =hex2byte(message);
outputStream.write(asd);