如何在java中自定义xml文件中的xml格式

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
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;

try {
    DocumentBuilderFactory docFactory = DocumentBuilderFactory.newInstance();
    DocumentBuilder docBuilder = docFactory.newDocumentBuilder();

    // 创建根元素
    Document doc = docBuilder.newDocument();
    Element rootElement = doc.createElement("root");
    doc.appendChild(rootElement);

    // 创建子元素
    Element childElement = doc.createElement("child");
    rootElement.appendChild(childElement);

    // 设置子元素的属性
    childElement.setAttribute("attribute", "value");

    // 创建文本节点并将其添加到子元素中
    childElement.appendChild(doc.createTextNode("Text content"));

    // 将文档写入XML文件
    TransformerFactory transformerFactory = TransformerFactory.newInstance();
    Transformer transformer = transformerFactory.newTransformer();
    DOMSource source = new DOMSource(doc);
    StreamResult result = new StreamResult(new File("custom.xml"));
    transformer.transform(source, result);

    System.out.println("XML文件创建成功！");
} catch (ParserConfigurationException | TransformerException e) {
    e.printStackTrace();
}

try {
    File xmlFile = new File("custom.xml");
    DocumentBuilderFactory docFactory = DocumentBuilderFactory.newInstance();
    DocumentBuilder docBuilder = docFactory.newDocumentBuilder();
    Document doc = docBuilder.parse(xmlFile);

    // 获取根元素
    Element rootElement = doc.getDocumentElement();

    // 获取子元素列表
    NodeList childNodes = rootElement.getChildNodes();

    // 遍历子元素
    for (int i = 0; i < childNodes.getLength(); i++) {
        Node childNode = childNodes.item(i);

        // 检查节点类型是否为元素
        if (childNode.getNodeType() == Node.ELEMENT_NODE) {
            Element childElement = (Element) childNode;

            // 获取子元素的属性
            String attribute = childElement.getAttribute("attribute");

            // 获取子元素的文本内容
            String textContent = childElement.getTextContent();

            System.out.println("子元素属性：" + attribute);
            System.out.println("子元素文本内容：" + textContent);
        }
    }
} catch (Exception e) {
    e.printStackTrace();
}