public static String binaryUrlencode(byte[] bytes) {
    return binaryUrlencode(bytes, 0, bytes.length);
  }

  public static String binaryUrlencode(byte[] bytes, int ofs, int len) {
    StringBuilder stringBuilder = new StringBuilder(len*3);
    for (int i = 0; i < len; i++) {
      stringBuilder.append("%");
      String s = "0" + Integer.toHexString(bytes[ofs+i]);
      stringBuilder.append(s.substring(s.length()-2, s.length()));
    }
    return stringBuilder.toString().toUpperCase();
  }

Began life as a copy of #2000460