Java HTML/XML - 如何更新属性

import java.io.StringReader;
import java.io.StringWriter;

import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

import org.w3c.dom.Attr;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.xml.sax.InputSource;

public class Main {
  public static String getXMLData() {
    return "<a><person number='' dept=''><name>myName</name></person></a>";
  }

  public static void main(String[] argv) throws Exception {
    DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
    Document doc = factory.newDocumentBuilder().parse(
        new InputSource(new StringReader(getXMLData())));

    dupAttributes(doc);

    System.out.println(documentToString(doc));

  }
  public static void dupAttributes(Document doc) {
    Element root = doc.getDocumentElement();
    Element personOne = (Element)root.getFirstChild();

    Attr deptAttr = personOne.getAttributeNode("dept");
    personOne.removeAttributeNode(deptAttr);
    String deptString = deptAttr.getValue();
    personOne.setAttribute("dept",deptString+"updated");

    String mailString = personOne.getAttribute("mail");
    personOne.setAttribute("mail",mailString+"updated");
    
    String titleString = personOne.getAttribute("title");
    //personOne.removeAttribute("title");
    personOne.setAttribute("title",titleString+"updated");
  }


  public static String documentToString(Document document) {
    try {
      TransformerFactory tf = TransformerFactory.newInstance();
      Transformer trans = tf.newTransformer();
      StringWriter sw = new StringWriter();
      trans.transform(new DOMSource(document), new StreamResult(sw));
      return sw.toString();
    } catch (TransformerException tEx) {
      tEx.printStackTrace();
    }
    return null;
  }
}