import java.io.File;
import java.io.IOException;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;
public class DomBuilder {
 public static void main(String[] args) {
  File docfile = new File("books.xml");
  Document doc = null;
  try {
   DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
   dbf.setNamespaceAware(true);
   DocumentBuilder db = dbf.newDocumentBuilder();
   doc = db.parse(docfile);
                                  Element root = doc.getDocumentElement();
   System.out.println("The root element is "+root.getNodeName());
                                 NodeList titles = root.getElementsByTagName("title");
   for(int titlenum=0;titlenum<titles.getLength();titlenum++){
    System.out.println("before change title :"+titles.item(titlenum).getFirstChild().getNodeValue());
   }
   DomBuilder.changebook(root, "title", "processed");
   NodeList titlesed = doc.getElementsByTagName("title");
   for(int titlenum=0;titlenum<titlesed.getLength();titlenum++){
    System.out.println("After change title :"+titlesed.item(titlenum).getFirstChild().getNodeValue());
   }
  } catch (ParserConfigurationException e) {
   System.out.println("The parser was not configured correctly.");
   System.exit(1);
  } catch (SAXException e) {
   System.out.println("Problem parsing the file.");
   System.exit(1);
  } catch (IOException e) {
   System.out.println("Cannot read input file.");
   System.exit(1);
  }

 }
 private static void changebook(Node start,String eleName,String eleValue){
  if(start.getNodeName().equals(eleName)){
   start.getFirstChild().setNodeValue(eleValue);
   System.out.println("set value finished !");
  }
  System.out.println("executed !");
  for(Node child=start.getFirstChild();child!=null;child=start.getNextSibling()){
   changebook(child,eleName,eleValue);
   System.out.println("递归调用 ！");
  }
  
 }

}

执行之后，没有修改成功，有哪位高手能指点一下？谢谢！