java使用XPath表达式解析xml节点，xpath表达式xml节点,public stati

java使用XPath表达式解析xml节点，xpath表达式xml节点,public stati

public static void examineXmlFile(String path) throws Exception {        DocumentBuilderFactory domFactory = DocumentBuilderFactory.newInstance();        domFactory.setNamespaceAware(true); // never forget this!        DocumentBuilder builder = domFactory.newDocumentBuilder();        Document doc = builder.parse(path);        XPathFactory factory = XPathFactory.newInstance();        XPath xpath = factory.newXPath();        XPathExpression expr = xpath.compile("//node/@id");        Object result = expr.evaluate(doc, XPathConstants.NODESET);        NodeList nodes = (NodeList) result;        for (int i = 0; i < nodes.getLength(); i++) {            Node n = nodes.item(i);            System.out.println(nodes.item(i).getNodeValue());        }    }

另一个使用xPath的示例：ReadXMLbyXPath

package util.xml;import java.io.File;import java.io.IOException;import javax.xml.parsers.DocumentBuilder;import javax.xml.parsers.DocumentBuilderFactory;import javax.xml.parsers.ParserConfigurationException;import javax.xml.xpath.XPath;import javax.xml.xpath.XPathConstants;import javax.xml.xpath.XPathExpressionException;import javax.xml.xpath.XPathFactory;import org.w3c.dom.Document;import org.w3c.dom.Node;import org.xml.sax.InputSource;import org.xml.sax.SAXException;import com.sun.org.apache.xpath.internal.NodeSet;public class ReadXMLbyXPath {  public static void main(String[] arg ) throws XPathExpressionException, ParserConfigurationException, SAXException, IOException  {     // parse the XML as a W3C Document     DocumentBuilder builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();     Document document = builder.parse(new File("E:/workspace/Java-Util/src/util/xml/widgets.xml"));     XPath xpath = XPathFactory.newInstance().newXPath();     String expression = "/widgets/widget";     Node widgetNode = (Node) xpath.evaluate(expression, document, XPathConstants.NODE);     System.out.println(widgetNode.getNodeName());//节点名称     System.out.println(widgetNode.getNodeValue());//节点值是null，为什么？     System.out.println(widgetNode.getTextContent());//节点text  }}

XML文件：widgets.xml

<widgets><widget value="widgetValue">widText</widget></widgets>