工具集

1.xml字符串的转义，主要用于在html页面中显示xml内容
 

    /**
       * Escapes '&', '<', '>', '"', and '\'' to their XML entity equivalents.
       */
      public static String escapeXml(String unescaped) {
        StringBuilder builder = new StringBuilder();
        escapeXml(unescaped, 0, unescaped.length(), true, builder);
        return builder.toString();
      }
      
      /**
       * Escapes '&', '<', '>', '"', and optionally ''' to their XML entity
       * equivalents. The portion of the input string between start (inclusive) and
       * end (exclusive) is scanned.  The output is appended to the given
       * StringBuilder.
       * 
       * @param code the input String
       * @param start the first character position to scan.
       * @param end the character position following the last character to scan.
       * @param quoteApostrophe if true, the &apos; character is quoted as
       *     &amp;apos;
       * @param builder a StringBuilder to be appended with the output.
       */
      public static void escapeXml(String code, int start, int end,
          boolean quoteApostrophe, StringBuilder builder) {
        int lastIndex = 0;
        int len = end - start;
        char[] c = new char[len];
        
        code.getChars(start, end, c, 0);
        for (int i = 0; i < len; i++) {
          switch (c[i]) {
            case '&':
              builder.append(c, lastIndex, i - lastIndex);
              builder.append("&amp;");
              lastIndex = i + 1;
              break;
            case '>':
              builder.append(c, lastIndex, i - lastIndex);
              builder.append("&gt;");
              lastIndex = i + 1;
              break;
            case '<':
              builder.append(c, lastIndex, i - lastIndex);
              builder.append("&lt;");
              lastIndex = i + 1;
              break;
            case '\"':
              builder.append(c, lastIndex, i - lastIndex);
              builder.append("&quot;");
              lastIndex = i + 1;
              break;
            case '\'':
              if (quoteApostrophe) {
                builder.append(c, lastIndex, i - lastIndex);
                builder.append("&apos;");
                lastIndex = i + 1;
              }
              break;
            default:
              break;
          }
        }
        builder.append(c, lastIndex, len - lastIndex);
      }