gistfile1.java

	public static String bytesToHex(byte[] data) {
		if (data==null) {
			 return null;
		} else {
			int len = data.length;
			String str = "";
			for (int i=0; i<len; i++) {
				if ((data[i]&0xFF)<16) {
					str = str + "0" + java.lang.Integer.toHexString(data[i]&0xFF);
				} else {
					str = str + java.lang.Integer.toHexString(data[i]&0xFF);
				}
			}
			return str;
		}
	}
	
	public static byte[] hexToBytes(String str) {
		if (str==null) {
			return null;
		} else if (str.length() < 2) {
			return null;
		} else {
			int len = str.length() / 2;
			byte[] buffer = new byte[len];
			for (int i=0; i<len; i++) {
				buffer[i] = (byte) Integer.parseInt(str.substring(i*2,i*2+2),16);
			}
			return buffer;
		}
	}