stringutil.java

google的gdata api包

                v = v*8 + (s.charAt(i++) - '0');
              }
              if ((i < len) && isOctal(s.charAt(i))) {
                v = v*8 + (s.charAt(i++) - '0');
              }
              c = (char)v;
            } else {
              // Propagate unknown escape sequences.
              sb.append('\\');
            }
            break;
          }
        }
      }
      sb.append(c);
    }
    return sb.toString();
  }

  /**
   * Unescape any MySQL escape sequences.
   * See MySQL language reference Chapter 6 at
   * <a href="http://www.mysql.com/doc/">http://www.mysql.com/doc/</a>.
   * This function will <strong>not</strong> work for other SQL-like
   * dialects.
   * @param s string to unescape, with the surrounding quotes.
   * @return unescaped string, without the surrounding quotes.
   * @exception IllegalArgumentException if s is not a valid MySQL string.
   */
  public static String unescapeMySQLString(String s)
      throws IllegalArgumentException {
    // note: the same buffer is used for both reading and writing
    // it works because the writer can never outrun the reader
    char chars[] = s.toCharArray();

    // the string must be quoted 'like this' or "like this"
    if (chars.length < 2 || chars[0] != chars[chars.length-1] ||
        (chars[0] != '\'' && chars[0] != '"')) {
      throw new IllegalArgumentException("not a valid MySQL string: " + s);
    }

    // parse the string and decode the backslash sequences; in addition,
    // quotes can be escaped 'like this: ''', "like this: """, or 'like this: "'
    int j = 1;  // write position in the string (never exceeds read position)
    int f = 0;  // state: 0 (normal), 1 (backslash), 2 (quote)
    for (int i = 1; i < chars.length - 1; i++) {
      if (f == 0) {             // previous character was normal
	if (chars[i] == '\\') {
	  f = 1;  // backslash
	} else if (chars[i] == chars[0]) {
	  f = 2;  // quoting character
	} else {
	  chars[j++] = chars[i];
	}
      } else if (f == 1) {      // previous character was a backslash
	switch (chars[i]) {
	  case '0':   chars[j++] = '\0';   break;
	  case '\'':  chars[j++] = '\'';   break;
	  case '"':   chars[j++] = '"';    break;
	  case 'b':   chars[j++] = '\b';   break;
	  case 'n':   chars[j++] = '\n';   break;
	  case 'r':   chars[j++] = '\r';   break;
	  case 't':   chars[j++] = '\t';   break;
	  case 'z':   chars[j++] = '\032'; break;
	  case '\\':  chars[j++] = '\\';   break;
	  default:
	    // if the character is not special, backslash disappears
	    chars[j++] = chars[i];
	    break;
	}
	f = 0;
      } else {                  // previous character was a quote
	// quoting characters must be doubled inside a string
	if (chars[i] != chars[0]) {
	  throw new IllegalArgumentException("not a valid MySQL string: " + s);
	}
	chars[j++] = chars[0];
	f = 0;
      }
    }
    // string contents cannot end with a special character
    if (f != 0) {
      throw new IllegalArgumentException("not a valid MySQL string: " + s);
    }

    // done
    return new String(chars, 1, j - 1);
  }

  static Map<String, Character> escapeStrings;

  static {
    // HTML character entity references as defined in HTML 4
    // see http://www.w3.org/TR/REC-html40/sgml/entities.html
    escapeStrings = new HashMap<String, Character>(252);

    escapeStrings.put("&nbsp;", new Character('\u00A0'));
    escapeStrings.put("&iexcl;", new Character('\u00A1'));
    escapeStrings.put("&cent;", new Character('\u00A2'));
    escapeStrings.put("&pound;", new Character('\u00A3'));
    escapeStrings.put("&curren;", new Character('\u00A4'));
    escapeStrings.put("&yen;", new Character('\u00A5'));
    escapeStrings.put("&brvbar;", new Character('\u00A6'));
    escapeStrings.put("&sect;", new Character('\u00A7'));
    escapeStrings.put("&uml;", new Character('\u00A8'));
    escapeStrings.put("&copy;", new Character('\u00A9'));
    escapeStrings.put("&ordf;", new Character('\u00AA'));
    escapeStrings.put("&laquo;", new Character('\u00AB'));
    escapeStrings.put("&not;", new Character('\u00AC'));
    escapeStrings.put("&shy;", new Character('\u00AD'));
    escapeStrings.put("&reg;", new Character('\u00AE'));
    escapeStrings.put("&macr;", new Character('\u00AF'));
    escapeStrings.put("&deg;", new Character('\u00B0'));
    escapeStrings.put("&plusmn;", new Character('\u00B1'));
    escapeStrings.put("&sup2;", new Character('\u00B2'));
    escapeStrings.put("&sup3;", new Character('\u00B3'));
    escapeStrings.put("&acute;", new Character('\u00B4'));
    escapeStrings.put("&micro;", new Character('\u00B5'));
    escapeStrings.put("&para;", new Character('\u00B6'));
    escapeStrings.put("&middot;", new Character('\u00B7'));
    escapeStrings.put("&cedil;", new Character('\u00B8'));
    escapeStrings.put("&sup1;", new Character('\u00B9'));
    escapeStrings.put("&ordm;", new Character('\u00BA'));
    escapeStrings.put("&raquo;", new Character('\u00BB'));
    escapeStrings.put("&frac14;", new Character('\u00BC'));
    escapeStrings.put("&frac12;", new Character('\u00BD'));
    escapeStrings.put("&frac34;", new Character('\u00BE'));
    escapeStrings.put("&iquest;", new Character('\u00BF'));
    escapeStrings.put("&Agrave;", new Character('\u00C0'));
    escapeStrings.put("&Aacute;", new Character('\u00C1'));
    escapeStrings.put("&Acirc;", new Character('\u00C2'));
    escapeStrings.put("&Atilde;", new Character('\u00C3'));
    escapeStrings.put("&Auml;", new Character('\u00C4'));
    escapeStrings.put("&Aring;", new Character('\u00C5'));
    escapeStrings.put("&AElig;", new Character('\u00C6'));
    escapeStrings.put("&Ccedil;", new Character('\u00C7'));
    escapeStrings.put("&Egrave;", new Character('\u00C8'));
    escapeStrings.put("&Eacute;", new Character('\u00C9'));
    escapeStrings.put("&Ecirc;", new Character('\u00CA'));
    escapeStrings.put("&Euml;", new Character('\u00CB'));
    escapeStrings.put("&Igrave;", new Character('\u00CC'));
    escapeStrings.put("&Iacute;", new Character('\u00CD'));
    escapeStrings.put("&Icirc;", new Character('\u00CE'));
    escapeStrings.put("&Iuml;", new Character('\u00CF'));
    escapeStrings.put("&ETH;", new Character('\u00D0'));
    escapeStrings.put("&Ntilde;", new Character('\u00D1'));
    escapeStrings.put("&Ograve;", new Character('\u00D2'));
    escapeStrings.put("&Oacute;", new Character('\u00D3'));
    escapeStrings.put("&Ocirc;", new Character('\u00D4'));
    escapeStrings.put("&Otilde;", new Character('\u00D5'));
    escapeStrings.put("&Ouml;", new Character('\u00D6'));
    escapeStrings.put("&times;", new Character('\u00D7'));
    escapeStrings.put("&Oslash;", new Character('\u00D8'));
    escapeStrings.put("&Ugrave;", new Character('\u00D9'));
    escapeStrings.put("&Uacute;", new Character('\u00DA'));
    escapeStrings.put("&Ucirc;", new Character('\u00DB'));
    escapeStrings.put("&Uuml;", new Character('\u00DC'));
    escapeStrings.put("&Yacute;", new Character('\u00DD'));
    escapeStrings.put("&THORN;", new Character('\u00DE'));
    escapeStrings.put("&szlig;", new Character('\u00DF'));
    escapeStrings.put("&agrave;", new Character('\u00E0'));
    escapeStrings.put("&aacute;", new Character('\u00E1'));
    escapeStrings.put("&acirc;", new Character('\u00E2'));
    escapeStrings.put("&atilde;", new Character('\u00E3'));
    escapeStrings.put("&auml;", new Character('\u00E4'));
    escapeStrings.put("&aring;", new Character('\u00E5'));
    escapeStrings.put("&aelig;", new Character('\u00E6'));
    escapeStrings.put("&ccedil;", new Character('\u00E7'));
    escapeStrings.put("&egrave;", new Character('\u00E8'));
    escapeStrings.put("&eacute;", new Character('\u00E9'));
    escapeStrings.put("&ecirc;", new Character('\u00EA'));
    escapeStrings.put("&euml;", new Character('\u00EB'));
    escapeStrings.put("&igrave;", new Character('\u00EC'));
    escapeStrings.put("&iacute;", new Character('\u00ED'));
    escapeStrings.put("&icirc;", new Character('\u00EE'));
    escapeStrings.put("&iuml;", new Character('\u00EF'));
    escapeStrings.put("&eth;", new Character('\u00F0'));
    escapeStrings.put("&ntilde;", new Character('\u00F1'));
    escapeStrings.put("&ograve;", new Character('\u00F2'));
    escapeStrings.put("&oacute;", new Character('\u00F3'));
    escapeStrings.put("&ocirc;", new Character('\u00F4'));
    escapeStrings.put("&otilde;", new Character('\u00F5'));
    escapeStrings.put("&ouml;", new Character('\u00F6'));
    escapeStrings.put("&divide;", new Character('\u00F7'));
    escapeStrings.put("&oslash;", new Character('\u00F8'));
    escapeStrings.put("&ugrave;", new Character('\u00F9'));
    escapeStrings.put("&uacute;", new Character('\u00FA'));
    escapeStrings.put("&ucirc;", new Character('\u00FB'));
    escapeStrings.put("&uuml;", new Character('\u00FC'));
    escapeStrings.put("&yacute;", new Character('\u00FD'));
    escapeStrings.put("&thorn;", new Character('\u00FE'));
    escapeStrings.put("&yuml;", new Character('\u00FF'));
    escapeStrings.put("&fnof;", new Character('\u0192'));
    escapeStrings.put("&Alpha;", new Character('\u0391'));
    escapeStrings.put("&Beta;", new Character('\u0392'));
    escapeStrings.put("&Gamma;", new Character('\u0393'));
    escapeStrings.put("&Delta;", new Character('\u0394'));
    escapeStrings.put("&Epsilon;", new Character('\u0395'));
    escapeStrings.put("&Zeta;", new Character('\u0396'));
    escapeStrings.put("&Eta;", new Character('\u0397'));
    escapeStrings.put("&Theta;", new Character('\u0398'));
    escapeStrings.put("&Iota;", new Character('\u0399'));
    escapeStrings.put("&Kappa;", new Character('\u039A'));
    escapeStrings.put("&Lambda;", new Character('\u039B'));
    escapeStrings.put("&Mu;", new Character('\u039C'));
    escapeStrings.put("&Nu;", new Character('\u039D'));
    escapeStrings.put("&Xi;", new Character('\u039E'));
    escapeStrings.put("&Omicron;", new Character('\u039F'));
    escapeStrings.put("&Pi;", new Character('\u03A0'));
    escapeStrings.put("&Rho;", new Character('\u03A1'));
    escapeStrings.put("&Sigma;", new Character('\u03A3'));
    escapeStrings.put("&Tau;", new Character('\u03A4'));
    escapeStrings.put("&Upsilon;", new Character('\u03A5'));
    escapeStrings.put("&Phi;", new Character('\u03A6'));
    escapeStrings.put("&Chi;", new Character('\u03A7'));
    escapeStrings.put("&Psi;", new Character('\u03A8'));
    escapeStrings.put("&Omega;", new Character('\u03A9'));
    escapeStrings.put("&alpha;", new Character('\u03B1'));
    escapeStrings.put("&beta;", new Character('\u03B2'));
    escapeStrings.put("&gamma;", new Character('\u03B3'));
    escapeStrings.put("&delta;", new Character('\u03B4'));
    escapeStrings.put("&epsilon;", new Character('\u03B5'));
    escapeStrings.put("&zeta;", new Character('\u03B6'));
    escapeStrings.put("&eta;", new Character('\u03B7'));
    escapeStrings.put("&theta;", new Character('\u03B8'));
    escapeStrings.put("&iota;", new Character('\u03B9'));
    escapeStrings.put("&kappa;", new Character('\u03BA'));
    escapeStrings.put("&lambda;", new Character('\u03BB'));
    escapeStrings.put("&mu;", new Character('\u03BC'));
    escapeStrings.put("&nu;", new Character('\u03BD'));
    escapeStrings.put("&xi;", new Character('\u03BE'));
    escapeStrings.put("&omicron;", new Character('\u03BF'));
    escapeStrings.put("&pi;", new Character('\u03C0'));
    escapeStrings.put("&rho;", new Character('\u03C1'));
    escapeStrings.put("&sigmaf;", new Character('\u03C2'));
    escapeStrings.put("&sigma;", new Character('\u03C3'));
    escapeStrings.put("&tau;", new Character('\u03C4'));
    escapeStrings.put("&upsilon;", new Character('\u03C5'));
    escapeStrings.put("&phi;", new Character('\u03C6'));
    escapeStrings.put("&chi;", new Character('\u03C7'));
    escapeStrings.put("&psi;", new Character('\u03C8'));
    escapeStrings.put("&omega;", new Character('\u03C9'));
    escapeStrings.put("&thetasym;", new Character('\u03D1'));
    escapeStrings.put("&upsih;", new Character('\u03D2'));
    escapeStrings.put("&piv;", new Character('\u03D6'));
    escapeStrings.put("&bull;", new Character('\u2022'));
    escapeStrings.put("&hellip;", new Character('\u2026'));
    escapeStrings.put("&prime;", new Character('\u2032'));
    escapeStrings.put("&Prime;", new Character('\u2033'));
    escapeStrings.put("&oline;", new Character('\u203E'));
    escapeStrings.put("&frasl;", new Character('\u2044'));
    escapeStrings.put("&weierp;", new Character('\u2118'));
    escapeStrings.put("&image;", new Character('\u2111'));
    escapeStrings.put("&real;", new Character('\u211C'));
    escapeStrings.put("&trade;", new Character('\u2122'));
    escapeStrings.put("&alefsym;", new Character('\u2135'));
    escapeStrings.put("&larr;", new Character('\u2190'));
    escapeStrings.put("&uarr;", new Character('\u2191'));
    escapeStrings.put("&rarr;", new Character('\u2192'));
    escapeStrings.put("&darr;", new Character('\u2193'));
    escapeStrings.put("&harr;", new Character('\u2194'));
    escapeStrings.put("&crarr;", new Character('\u21B5'));
    escapeStrings.put("&lArr;", new Character('\u21D0'));
    escapeStrings.put("&uArr;", new Character('\u21D1'));
    escapeStrings.put("&rArr;", new Character('\u21D2'));
    escapeStrings.put("&dArr;", new Character('\u21D3'));
    escapeStrings.put("&hArr;", new Character('\u21D4'));
    escapeStrings.put("&forall;", new Character('\u2200'));
    escapeStrings.put("&part;", new Character('\u2202'));
    escapeStrings.put("&exist;", new Character('\u2203'));
    escapeStrings.put("&empty;", new Character('\u2205'));
    escapeStrings.put("&nabla;", new Character('\u2207'));
    escapeStrings.put("&isin;", new Character('\u2208'));
    escapeStrings.put("&notin;", new Character('\u2209'));
    escapeStrings.put("&ni;", new Character('\u220B'));
    escapeStrings.put("&prod;", new Character('\u220F'));
    escapeStrings.put("&sum;", new Character('\u2211'));
    escapeStrings.put("&minus;", new Character('\u2212'));
    escapeStrings.put("&lowast;", new Character('\u2217'));
    escapeStrings.put("&radic;", new Character('\u221A'));
    escapeStrings.put("&prop;", new Character('\u221D'));
    escapeStrings.put("&infin;", new Character('\u221E'));
    escapeStrings.put("&ang;", new Character('\u2220'));
    escapeStrings.put("&and;", new Character('\u2227'));
    escapeStrings.put("&or;", new Character('\u2228'));
    escapeStrings.put("&cap;", new Character('\u2229'));
    escapeStrings.put("&cup;", new Character('\u222A'));
    escapeStrings.put("&int;", new Character('\u222B'));
    escapeStrings.put("&there4;", new Character('\u2234'));
    escapeStrings.put("&sim;", new Character('\u223C'));
    escapeStrings.put("&cong;", new Character('\u2245'));
    escapeStrings.put("&asymp;", new Character('\u2248'));
    escapeStrings.put("&ne;", new Character('\u2260'));
    escapeStrings.put("&equiv;", new Character('\u2261'));
    escapeStrings.put("&le;", new Character('\u2264'));
    escapeStrings.put("&ge;", new Character('\u2265'));
    escapeStrings.put("&sub;", new Character('\u2282'));
    escapeStrings.put("&sup;", new Character('\u2283'));
    escapeStrings.put("&nsub;", new Character('\u2284'));
    escapeStrings.put("&sube;", new Character('\u2286'));
    escapeStrings.put("&supe;", new Character('\u2287'));
    escapeStrings.put("&oplus;", new Character('\u2295'));
    escapeStrings.put("&otimes;", new Character('\u2297'));
    escapeStrings.put("&perp;", new Character('\u22A5'));
    escapeStrings.put("&sdot;", new Character('\u22C5'));
    escapeStrings.put("&lceil;", new Character('\u2308'));
    escapeStrings.put("&rceil;", new Character('\u2309'));
    escapeStrings.put("&lfloor;", new Character('\u230A'));
    escapeStrings.put("&rfloor;", new Character('\u230B'));
    escapeStrings.put("&lang;", new Character('\u2329'));
    escapeStrings.put("&rang;", new Character('\u232A'));
    escapeStrings.put("&loz;", new Character('\u25CA'));
    escapeStrings.put("&spades;", new Character('\u2660'));
    escapeStrings.put("&clubs;", new Character('\u2663'));
    escapeStrings.put("&hearts;", new Character('\u2665'));
    escapeStrings.put("&diams;", new Character('\u2666'));
    escapeStrings.put("&quot;", new Character('\u0022'));
    escapeStrings.put("&amp;", new Character('\u0026'));
    escapeStrings.put("&lt;", new Character('\u003C'));
    escapeStrings.put("&gt;", new Character('\u003E'));
    escapeStrings.put("&OElig;", new Character('\u0152'));
    escapeStrings.put("&oelig;", new Character('\u0153'));
    escapeStrings.put("&Scaron;", new Character('\u0160'));
    escapeStrings.put("&scaron;", new Character('\u0161'));
    escapeStrings.put("&Yuml;", new Character('\u0178'));
    escapeStrings.put("&circ;", new Character('\u02C6'));
    escapeStrings.put("&tilde;", new Character('\u02DC'));
    escapeStrings.put("&ensp;", new Character('\u2002'));
    escapeStrings.put("&emsp;", new Character('\u2003'));
    escapeStrings.put("&thinsp;", new Character('\u2009'));
    escapeStrings.put("&zwnj;", new Character('\u200C'));
    escapeStrings.put("&zwj;", new Character('\u200D'));
    escapeStrings.put("&lrm;", new Character('\u200E'));
    escapeStrings.put("&rlm;", new Character('\u200F'));
    escapeStrings.put("&ndash;", new Character('\u2013'));
    escapeStrings.put("&mdash;", new Character('\u2014'));
    escapeStrings.put("&lsquo;", new Character('\u2018'));
    escapeStrings.put("&rsquo;", new Character('\u2019'));
    escapeStrings.put("&sbquo;", new Character('\u201A'));
    escapeStrings.put("&ldquo;", new Character('\u201C'));
    escapeStrings.put("&rdquo;", new Character('\u201D'));
    escapeStrings.put("&bdquo;", new Character('\u201E'));
    escapeStrings.put("&dagger;", new Character('\u2020'));
    escapeStrings.put("&Dagger;", new Character('\u2021'));
    escapeStrings.put("&permil;", new Character('\u2030'));
    escapeStrings.put("&lsaquo;", new Character('\u2039'));
    escapeStrings.put("&rsaquo;", new Character('\u203A'));
    escapeStrings.put("&euro;", new Character('\u20AC'));
  }

  /**
   * Replace all the occurences of HTML escape strings with the
   * respective characters.
   *
   * @param s a <code>String</code> value
   * @return a <code>String</code> value
   */
  public static final String unescapeHTML(String s) {
    char[] chars = s.toCharArray();
    char[] escaped = new char[chars.length];

    // Note: escaped[pos] = end of the escaped char array.
    int pos = 0;

    for (int i = 0; i < chars.length;) {
      if (chars[i] != '&') {
        escaped[pos++] = chars[i++];
        continue;
      }

      // Allow e.g. &#123;
      int j = i + 1;
      if (j < chars.length && chars[j] == '#')
        j++;

      // Scan until we find a char that is not letter or digit.
      for (; j < chars.length; j++) {