import java.io.IOException;
import java.io.StringWriter;
import java.util.List;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.XMLWriter;

public class Dom4JHandle {

    private static final String xmlString = "<books><book price=\"108\"><name>Java编程思想</name><author>Bruce Eckel</author></book><book price=\"52\"><name>Effective Java</name><author>Joshua Bloch</author></book><book price=\"118\"><name>Java 7入门经典</name><author>Ivor Horton</author></book></books>";
    
    public static void main(String[] args) {
        parseXml(xmlString);
        assembleXml();
    }
    
    public static void parseXml(String xmlString) {
        try {
            Document doc = DocumentHelper.parseText(xmlString);
            Element root = doc.getRootElement();
            @SuppressWarnings("unchecked")
            List<Element> elements = root.elements();
            for(Element element : elements) {
                System.out.println("name=" + element.elementText("name") + "\tauthor=" + element.elementText("author")
                        + "\tprice=" + element.attributeValue("price"));
            }
        } catch (DocumentException e) {
            e.printStackTrace();
        }
    }
    
    public static String assembleXml() {
        Document doc = DocumentHelper.createDocument();
        Element root = doc.addElement("books");
        Element book = root.addElement("book");
        book.addAttribute("price", "108");
        book.addElement("name").setText("Java编程思想");
        book.addElement("author").setText("Bruce Eckel");
        book = root.addElement("book");
        book.addAttribute("price", "52");
        book.addElement("name").setText("Effective Java");
        book.addElement("author").setText("Joshua Bloch");
        book = root.addElement("book");
        book.addAttribute("price", "118");
        book.addElement("name").setText("Java 7入门经典");
        book.addElement("author").setText("Ivor Horton");
        OutputFormat format = OutputFormat.createCompactFormat(); //createPrettyPrint() 层次格式化
        StringWriter writer = new StringWriter();
        XMLWriter output = new XMLWriter(writer, format);
        try {
            output.write(doc);
            writer.close();
            output.close();
            System.out.println(writer.toString());
        } catch (IOException e) {
            e.printStackTrace();
            return null;
        }
        return writer.toString();
    }
}

    http://www.w3school.com.cn/xpath/index.asp

import java.io.StringReader;
import java.util.List;

import org.jdom.Document;
import org.jdom.Element;
import org.jdom.input.SAXBuilder;
import org.jdom.output.Format;
import org.jdom.output.XMLOutputter;

public class JdomHandle {

    private static final String xmlString = "<books><book price=\"108\"><name>Java编程思想</name><author>Bruce Eckel</author></book><book price=\"52\"><name>Effective Java</name><author>Joshua Bloch</author></book><book price=\"118\"><name>Java 7入门经典</name><author>Ivor Horton</author></book></books>";

    public static void main(String[] args) {
        parseXml(xmlString);
        assembleXml();
    }

    public static void parseXml(String xmlString) {
        SAXBuilder builder = new SAXBuilder();
        Document doc = null;
        try {
            doc = builder.build(new StringReader(xmlString));
            Element root = doc.getRootElement(); // 根元素
            @SuppressWarnings("unchecked")
            List<Element> list = root.getChildren();
            if (list != null) {
                for (Element element : list) {
                    System.out.println("name=" + element.getChildText("name") + "\tauthor="
                            + element.getChildText("author") + "\tprice=" + element.getAttributeValue("price"));
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public static String assembleXml() {
        Document doc = new Document();
        Element root = new Element("books");
        Element book = new Element("book");
        Element name = new Element("name");
        Element author = new Element("author");
        book.setAttribute("price", "108");
        name.addContent("Java编程思想");
        author.addContent("Bruce Eckel");
        book.addContent(name);
        book.addContent(author);
        root.addContent(book);
        book = new Element("book");
        name = new Element("name");
        author = new Element("author");
        book.setAttribute("price", "52");
        name.addContent("Effective Java");
        author.addContent("Joshua Bloch");
        book.addContent(name);
        book.addContent(author);
        root.addContent(book);
        book = new Element("book");
        name = new Element("name");
        author = new Element("author");
        name.addContent("Java 7入门经典");
        author.addContent("Ivor Horton");
        book.setAttribute("price", "118");
        book.addContent(name);
        book.addContent(author);
        root.addContent(book);
        doc.addContent(root);
        XMLOutputter xo = new XMLOutputter(Format.getCompactFormat()); // getPrettyFormat() 层次格式化
        System.out.println(xo.outputString(doc));
        return xo.outputString(doc);
    }
}