code: public static boolean hasCharset(String ctype)
      {
          if (ctype == null)
          {
              return false;
          }
          Matcher matcher = CHARSET_PATT.matcher(ctype);
          if (matcher.find())
          {
              return true;
          }
          else
          {
              return false;
          }
      }
docs: Check if a content-type string has a charset field appended.
  
  @param ctype
  the content-type string
  @return true if {@code ctype} has a charset, false otherwise