To encode an URI you can simply use Java’s URLEncoder’s encode method which has been available since JDK 1.4.

String encodedUri;
  try {
    encodedUri = URLEncoder.encode(uri, "UTF-8");
  }
  catch (UnsupportedEncodingException exc) {
    // this should never happen
    logger.warn("UTF-8 is not a supported encoding?  Not encoding for now...", exc);
    encodedUri = uri;
  }