无法正确获取xml节点的最后一个节点

<root>
  <node1>...</node1>
  <node2>...</node2>
  <node3>...</node3>
</root>

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

// 加载XML文档
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document document = builder.parse("xml文件路径");

// 获取根节点
Node root = document.getDocumentElement();

// 获取最后一个节点
NodeList nodeList = root.getChildNodes();
Node lastNode = nodeList.item(nodeList.getLength() - 1);

<root>
  <node1>...</node1>
  <node2>...</node2>
  <node3>...</node3>
</root>

import org.xml.sax.Attributes;
import org.xml.sax.helpers.DefaultHandler;
import org.xml.sax.InputSource;
import javax.xml.parsers.SAXParserFactory;
import javax.xml.parsers.SAXParser;

// 定义回调函数处理器
class MyHandler extends DefaultHandler {
    private String lastNodeName;  // 记录最后一个节点名称

    // 开始元素的回调函数
    public void startElement(String uri, String localName, String qName, Attributes attributes) {
        lastNodeName = qName;
    }
    
    // 结束文档的回调函数
    public void endDocument() {
        System.out.println("Last node: " + lastNodeName);
    }
}

// 加载XML文档
SAXParserFactory factory = SAXParserFactory.newInstance();
SAXParser parser = factory.newSAXParser();
MyHandler handler = new MyHandler();
parser.parse(new InputSource("xml文件路径"), handler);