字符串转十六进制

这个方法是从蓝牙官方的Demo中的一小段功能中抽出来的

 private String b(String st) {        {            // For all other profiles, writes the data formatted in HEX.            final byte[] data = st.getBytes();            StringBuilder stringBuilder = new StringBuilder(                    data.length);            if (data != null && data.length > 0) {                for (byte byteChar : data)                    stringBuilder.append(String.format("%02X ", byteChar));//                System.out.println("ppp" + new String(data) + "\n"//                        + stringBuilder.toString());            }            return stringBuilder.toString();        }