Java HTML/XML - 如何使用XPath获取XML子元素

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

public class Main {
  public static void main(String[] args) throws Exception {
    DocumentBuilderFactory Factory = DocumentBuilderFactory.newInstance();
    DocumentBuilder builder = Factory.newDocumentBuilder();
    Document doc = builder.parse("myxml.xml");
    XPathFactory factory = XPathFactory.newInstance();
    XPath xpath = factory.newXPath();

    XPathExpression expr = xpath.compile("//" + "item1" + "/*");
    Object result = expr.evaluate(doc, XPathConstants.NODESET);
    NodeList nodes = (NodeList) result;
    System.out.println(nodes.getLength());
    for (int i = 0; i < nodes.getLength(); i++) {
      Element el = (Element) nodes.item(i);
      System.out.println("tag: " + el.getNodeName());
      if (el.getFirstChild().getNodeType() == Node.TEXT_NODE)
        System.out.println("inner value:" + el.getFirstChild().getNodeValue());

      NodeList children = el.getChildNodes();
      for (int k = 0; k < children.getLength(); k++) {
        Node child = children.item(k);
        if (child.getNodeType() != Node.TEXT_NODE) {
          System.out.println("child tag: " + child.getNodeName());
          if (child.getFirstChild().getNodeType() == Node.TEXT_NODE)
            System.out.println("inner child value:"
                + child.getFirstChild().getNodeValue());
        }
      }
    }
  }
}