Java HTML/XML - 如何在XPath中选择具有指定名称的文档中的所有节点

import java.io.File;

import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpression;
import javax.xml.xpath.XPathFactory;

import org.w3c.dom.Document;
import org.w3c.dom.NodeList;

public class Main {
  public static void main(String[] args) throws Exception {
    Document doc = DocumentBuilderFactory.newInstance().newDocumentBuilder()
        .parse(new File("Test.xml"));
    XPath xPath = XPathFactory.newInstance().newXPath();
    XPathExpression exp = xPath.compile("//data");
    NodeList nl = (NodeList) exp.evaluate(doc, XPathConstants.NODESET);
    System.out.println("Found " + nl.getLength() + " results");
  }

}