How to find sunstring with regular expression?

Question

How can I find a substring in a string with a regular expression?
Example:
I have a original string "<tr><th>RecordId: </th><td valign=middle>A4711</td></tr>"
Now i want to extract the value "A4711" from this string with a regular expression. Everything except "A4711" is fixed, the id "A4711" itself is dynamic. How is it possible to get the substring "A4711" of the original string with a regular expression?

Answer 1

i wrote a little method with the infos above to get such results:
     * Get all substrings of a string that matches a regular expression.
     * @param original String to inspect.
     * @param regExp Regular expression as search criteria.
     * @return All matches of <i>regExp</i> or null if one input parameter is null.
    public static String[] getSubstrings(String original, String regExp) {
        String[] result = null;
        if (original != null && regExp != null) {
            Pattern pattern = Pattern.compile(regExp);
            Matcher matcher = pattern.matcher(original);
            boolean matchFound = matcher.find();
            Vector matches = new Vector();
            while (matchFound) {
                String match = matcher.group();        
                matches.addElement(match);
                matchFound = matcher.find();
            }//next match
            int count = matches.size();
            result = new String[count];
            for (int i = 0; i < count; i++) {
                result[i] = (String) matches.elementAt(i);
            }//next match
        }//else: input unavailable
        return result;
    }//getSubstrings()