class ConvertUtil {

    public final static String bytesToHexString(byte[] bytes) {
        String result = "";
        String hex;
        for (byte b : bytes) {
            //字节高4位
            hex = String.valueOf(hexStr.charAt((b & 0xF0) >> 4));
            //字节低4位
            hex += String.valueOf(hexStr.charAt(b & 0x0F));
            result += hex + " ";
        }
        return result;
    }

}