Java WS:如何从模型对象构建ElementNSImpl？

public class Person {
    private String name;
    private int age;

    // 构造函数、getter和setter方法
    public Person() {}

    public Person(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }
}

import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;

@XmlRootElement(name = "person")
public class Person {
    private String name;
    private int age;

    // 构造函数、getter和setter方法
    // ...

    @XmlElement(name = "name")
    public String getName() {
        return name;
    }

    @XmlElement(name = "age")
    public int getAge() {
        return age;
    }
}

import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;
import java.io.StringWriter;

public class JAXBUtil {
    public static String convertToXml(Object obj) throws JAXBException {
        JAXBContext context = JAXBContext.newInstance(obj.getClass());
        Marshaller marshaller = context.createMarshaller();
        marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE);

        StringWriter sw = new StringWriter();
        marshaller.marshal(obj, sw);
        return sw.toString();
    }
}

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import java.io.StringReader;

public class XMLUtil {
    public static Element convertToElementNSImpl(String xml) throws ParserConfigurationException, SAXException, IOException {
        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        DocumentBuilder builder = factory.newDocumentBuilder();
        Document doc = builder.parse(new InputSource(new StringReader(xml)));
        return doc.getDocumentElement();
    }
}

public class Main {
    public static void main(String[] args) {
        try {
            Person person = new Person("John Doe", 30);
            String xml = JAXBUtil.convertToXml(person);
            Element elementNSImpl = XMLUtil.convertToElementNSImpl(xml);

            // 现在你有了一个ElementNSImpl实例
            System.out.println(elementNSImpl.getTextContent());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}