无法从XML获取具有JDOM的子属性

import org.jdom2.Document;
import org.jdom2.Element;
import org.jdom2.JDOMException;
import org.jdom2.input.SAXBuilder;
import org.jdom2.xpath.XPathExpression;
import org.jdom2.xpath.XPathFactory;

public class JDOMExample {
    public static void main(String[] args) {
        try {
            // 创建SAXBuilder对象
            SAXBuilder saxBuilder = new SAXBuilder();
            
            // 读取XML文件并构建Document对象
            Document document = saxBuilder.build("path/to/xml/file.xml");
            
            // 创建XPathFactory对象
            XPathFactory xPathFactory = XPathFactory.instance();
            
            // 编译XPath表达式
            XPathExpression<Element> xPathExpression = xPathFactory.compile("//parent/child[@attribute='value']", Filters.element());
            
            // 在文档中执行XPath表达式
            List<Element> elements = xPathExpression.evaluate(document);
            
            // 遍历匹配的元素并获取子属性
            for (Element element : elements) {
                String subAttribute = element.getChild("subElement").getAttributeValue("subAttribute");
                System.out.println("Sub Attribute: " + subAttribute);
            }
        } catch (JDOMException | IOException e) {
            e.printStackTrace();
        }
    }
}