如何在JAX-WS中更改响应xml

@WebService
public class MyWebService {
    @WebMethod
    public String processRequest(String xmlRequest) {
        // 解析接收到的XML请求
        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        DocumentBuilder builder;
        try {
            builder = factory.newDocumentBuilder();
            Document document = builder.parse(new InputSource(new StringReader(xmlRequest)));

            // 找到要更改的XML元素
            XPath xpath = XPathFactory.newInstance().newXPath();
            XPathExpression expr = xpath.compile("//elementToChange");
            Node node = (Node) expr.evaluate(document, XPathConstants.NODE);

            // 修改XML元素
            node.setTextContent("New Value");

            // 将修改后的XML转换为字符串
            TransformerFactory transformerFactory = TransformerFactory.newInstance();
            Transformer transformer = transformerFactory.newTransformer();
            StringWriter writer = new StringWriter();
            transformer.transform(new DOMSource(document), new StreamResult(writer));
            String modifiedXml = writer.getBuffer().toString();

            // 创建响应对象并返回
            return modifiedXml;
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }
}