java操作xpath

include http://www.ibm.com/developerworks/cn/xml/x-javaxpathapi.html
 
 

import java.io.IOException;
import org.w3c.dom.*;
import org.xml.sax.SAXException;
import javax.xml.parsers.*;
import javax.xml.xpath.*;

public class Main
{
    public static void main(String[] args) 
    throws ParserConfigurationException, SAXException, 
           IOException, XPathExpressionException {
        
        
     DocumentBuilderFactory domFactory = DocumentBuilderFactory.newInstance();
     domFactory.setNamespaceAware(true); // never forget this!
     DocumentBuilder builder = domFactory.newDocumentBuilder();
     Document doc = builder.parse("D:\\books.xml");
     
     XPathFactory factory = XPathFactory.newInstance();
     XPath xpath = factory.newXPath();
     XPathExpression expr = xpath.compile("//book[author='Neal Stephenson']/title/text()");

     Object result = expr.evaluate(doc, XPathConstants.NODESET);
     NodeList nodes = (NodeList) result;
     for (int i = 0; i < nodes.getLength(); i++) {
         System.out.println(nodes.item(i).getNodeValue()); 
     }
   }
}

 
book s.xml:
 
  

<inventory>
    <book year="2000">
        <title>Snow Crash</title>
        <author>Neal Stephenson</author>
        <publisher>Spectra</publisher>
        <isbn>0553380958</isbn>
        <price>14.95</price>
    </book>
 
    <book year="2005">
        <title>Burning Tower</title>
        <author>Larry Niven</author>
        <author>Jerry Pournelle</author>
        <publisher>Pocket</publisher>
        <isbn>0743416910</isbn>
        <price>5.99</price>
    <book>
 
    <book year="1995">
        <title>Zodiac</title>
        <author>Neal Stephenson<author>
        <publisher>Spectra</publisher>
        <isbn>0553573862</isbn>
        <price>7.50</price>
    <book>

    <!-- more books... -->
 
</inventory>