Java formaler Ausdruck aus XML Datei laden

ersetze.xml:

<root>

<ersetze>=<durch> = </durch> </ersetze>

<ersetze>\w\w<durch> </durch> </ersetze>

</root>

um im Java einen String zu durchsuchen und entsprechend zu ersetzen. Dies wird durch folgenden Code realisiert:

[c]

    private static String find_replace(String source) throws IOException,

            ParserConfigurationException, SAXException, XPathExpressionException {

        String result = new String(source);

        String ersetze = "";

        String durch = "";

        try {

            DocumentBuilderFactory factory_j =

                    DocumentBuilderFactory.newInstance();

            factory_j.setNamespaceAware(true);

            DocumentBuilder builder_j = factory_j.newDocumentBuilder();

            Document doc_j = builder_j.parse("T:\\ersetze.xml");

            XPathFactory xfactory_j = XPathFactory.newInstance();

            XPath xpath_j = xfactory_j.newXPath();

            XPathExpression expr_j = xpath_j.compile("//ersetze");

            Object result_j = expr_j.evaluate(doc_j,

                    XPathConstants.NODESET);

            NodeList nodes_j = (NodeList) result_j;

            for (int i = 0; i < nodes_j.getLength(); i++) {

                XPathExpression expr_j_se =

                        xpath_j.compile("self::*/text()");

                Object result_j_se = expr_j_se.evaluate(nodes_j.item(i),

                        XPathConstants.NODESET);

                NodeList nodes_j_se = (NodeList) result_j_se;

                ersetze = nodes_j_se.item(0).getNodeValue();

                expr_j_se = xpath_j.compile("self::*/durch/text()");

                result_j_se = expr_j_se.evaluate(nodes_j.item(i),

                        XPathConstants.NODESET);

                nodes_j_se = (NodeList) result_j_se;

                durch = nodes_j_se.item(0).getNodeValue();

                Pattern replace = Pattern.compile(ersetze.trim());

                Matcher matcher2 = replace.matcher(result);

                result = matcher2.replaceAll(durch);

            }

        } catch (Exception ex) {

            ex.printStackTrace();

        }

        return result;

    }