Re: Ahhh.. URL wants to get encoded. Does Java wanna?

Fellow Coders:

Thanks very much. Read all the fine answers, which put me on the
right track.

The simple goal is to produce a sitemap.xml, with the url properly
encoded (as specified at http://sitemaps.org/protocol.php).

An exemple, taken from this sitemaps.org:

http://www.example.com/Lmlat.php&q=name should become
http://www.example.com/%C3%BCmlat.php&q=name

(If the above is encoded by Google Group parser: Lmlaut => %C3%BCmlat
and & => &)

The code snippet posted by Wayne works ok, but the Lmlaut stays an
Lmlaut, since it is not part of the query.

And we can't URLEncode the whole string, since forward slashes and
other valid characters will be transformed in UTF8 char codes.

The brute force way to do it (and the only way I found could work with
the sitemap.org example) is to take the initial string, parse every
single char, replace <, >, & and " with their escaped version (&amp;,
&lt;, etc.) as Steven indicated, and finally test any remaining char
to be within the range \u0000 to \u007F (the Basic Latin block) and
encode any char outside that range with this class, taken straight out
of the W3C website (http://www.w3.org/International/O-URL-code.html):

/**********************************************************/

public class URLUTF8Encoder
{

  final static String[] hex = {
    "%00", "%01", "%02", "%03", "%04", "%05", "%06", "%07",
    "%08", "%09", "%0a", "%0b", "%0c", "%0d", "%0e", "%0f",
    "%10", "%11", "%12", "%13", "%14", "%15", "%16", "%17",
    "%18", "%19", "%1a", "%1b", "%1c", "%1d", "%1e", "%1f",
    "%20", "%21", "%22", "%23", "%24", "%25", "%26", "%27",
    "%28", "%29", "%2a", "%2b", "%2c", "%2d", "%2e", "%2f",
    "%30", "%31", "%32", "%33", "%34", "%35", "%36", "%37",
    "%38", "%39", "%3a", "%3b", "%3c", "%3d", "%3e", "%3f",
    "%40", "%41", "%42", "%43", "%44", "%45", "%46", "%47",
    "%48", "%49", "%4a", "%4b", "%4c", "%4d", "%4e", "%4f",
    "%50", "%51", "%52", "%53", "%54", "%55", "%56", "%57",
    "%58", "%59", "%5a", "%5b", "%5c", "%5d", "%5e", "%5f",
    "%60", "%61", "%62", "%63", "%64", "%65", "%66", "%67",
    "%68", "%69", "%6a", "%6b", "%6c", "%6d", "%6e", "%6f",
    "%70", "%71", "%72", "%73", "%74", "%75", "%76", "%77",
    "%78", "%79", "%7a", "%7b", "%7c", "%7d", "%7e", "%7f",
    "%80", "%81", "%82", "%83", "%84", "%85", "%86", "%87",
    "%88", "%89", "%8a", "%8b", "%8c", "%8d", "%8e", "%8f",
    "%90", "%91", "%92", "%93", "%94", "%95", "%96", "%97",
    "%98", "%99", "%9a", "%9b", "%9c", "%9d", "%9e", "%9f",
    "%a0", "%a1", "%a2", "%a3", "%a4", "%a5", "%a6", "%a7",
    "%a8", "%a9", "%aa", "%ab", "%ac", "%ad", "%ae", "%af",
    "%b0", "%b1", "%b2", "%b3", "%b4", "%b5", "%b6", "%b7",
    "%b8", "%b9", "%ba", "%bb", "%bc", "%bd", "%be", "%bf",
    "%c0", "%c1", "%c2", "%c3", "%c4", "%c5", "%c6", "%c7",
    "%c8", "%c9", "%ca", "%cb", "%cc", "%cd", "%ce", "%cf",
    "%d0", "%d1", "%d2", "%d3", "%d4", "%d5", "%d6", "%d7",
    "%d8", "%d9", "%da", "%db", "%dc", "%dd", "%de", "%df",
    "%e0", "%e1", "%e2", "%e3", "%e4", "%e5", "%e6", "%e7",
    "%e8", "%e9", "%ea", "%eb", "%ec", "%ed", "%ee", "%ef",
    "%f0", "%f1", "%f2", "%f3", "%f4", "%f5", "%f6", "%f7",
    "%f8", "%f9", "%fa", "%fb", "%fc", "%fd", "%fe", "%ff"
  };

  /**
   * Encode a string to the "x-www-form-urlencoded" form, enhanced
   * with the UTF-8-in-URL proposal. This is what happens:
   *
   * <ul>
   * <li><p>The ASCII characters 'a' through 'z', 'A' through 'Z',
   * and '0' through '9' remain the same.
   *
   * <li><p>The unreserved characters - _ . ! ~ * ' ( ) remain the
same.
   *
   * <li><p>The space character ' ' is converted into a plus sign '+'.
   *
   * <li><p>All other ASCII characters are converted into the
   * 3-character string "%xy", where xy is
   * the two-digit hexadecimal representation of the character
   * code
   *
   * <li><p>All non-ASCII characters are encoded in two steps: first
   * to a sequence of 2 or 3 bytes, using the UTF-8 algorithm;
   * secondly each of these bytes is encoded as "%xx".
   * </ul>
   *
   * @param s The string to be encoded
   * @return The encoded string
   */
  public static String encode(String s)
  {
    StringBuffer sbuf = new StringBuffer();
    int len = s.length();
    for (int i = 0; i < len; i++) {
      int ch = s.charAt(i);
      if ('A' <= ch && ch <= 'Z') { // 'A'..'Z'
        sbuf.append((char)ch);
      } else if ('a' <= ch && ch <= 'z') { // 'a'..'z'
           sbuf.append((char)ch);
      } else if ('0' <= ch && ch <= '9') { // '0'..'9'
           sbuf.append((char)ch);
      } else if (ch == ' ') { // space
           sbuf.append('+');
      } else if (ch == '-' || ch == '_' // unreserved
          || ch == '.' || ch == '!'
          || ch == '~' || ch == '*'
          || ch == '\'' || ch == '('
          || ch == ')') {
        sbuf.append((char)ch);
      } else if (ch <= 0x007f) { // other ASCII
           sbuf.append(hex[ch]);
      } else if (ch <= 0x07FF) { // non-ASCII <= 0x7FF
           sbuf.append(hex[0xc0 | (ch >> 6)]);
           sbuf.append(hex[0x80 | (ch & 0x3F)]);
      } else { // 0x7FF < ch <= 0xFFFF
           sbuf.append(hex[0xe0 | (ch >> 12)]);
           sbuf.append(hex[0x80 | ((ch >> 6) & 0x3F)]);
           sbuf.append(hex[0x80 | (ch & 0x3F)]);
      }
    }
    return sbuf.toString();
  }

}

/**********************************************************/

Are we having fun yet? In this particular case (a very common case),
1 line of PHP equals over 100 lines of Java. My KLOC just went
through the roof and my employer suggested I take a very long
vacation, in some remote location.

Thanks again all.