1. 解析XML的兩種方法
   

package cnslp.dom4j.com;
import java.io.File;
import java.util.Iterator;

import org.dom4j.Attribute;
import org.dom4j.Document;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;
/**
 * Created by cnslp on 2017/5/12 0012.
 * 解析XML文檔的兩種方法
 */


public class Demo {
    public static void main(String[] args) throws Exception {
        SAXReader reader = new SAXReader();//創建SAXReader讀取器，專門用於讀取xml
        File file = new File("books.xml");
        Document document = reader.read(file);
        Element root = document.getRootElement();
        //叠代方法
        Iterator it = root.elementIterator();
        while (it.hasNext()) {
            Element element = (Element) it.next();

           Iterator attrIt = element.attributeIterator();//叠代元素屬性
           while (attrIt.hasNext()) {
            Attribute a  = (Attribute) attrIt.next();
            System.out.println(a.getValue());
           }

           Iterator eleIt = element.elementIterator();//叠代子元素
           while (eleIt.hasNext()) {
            Element e = (Element) eleIt.next();
            System.out.println(e.getName() + ": " + e.getText());
           }
           System.out.println();
        }
    }

    /*   //List方法
        //根據saxReader的read重寫方法可知，既可以通過inputStream輸入流來讀取，也可以通過file對象來讀取
        //Document document = saxReader.read(inputStream);

        List<Element> childElements = root.elements();
        for (Element child : childElements) {
            System.out.println("element name:"+ child.getName());
            //未知屬性名情況下
            List<Attribute> attributeList = child.attributes();//獲取元素的所有屬性
           for (Attribute attr : attributeList) {
            System.out.println("name:"+attr.getName() + ": " + attr.getValue());
           }
           //已知屬性名情況下
           //System.out.println("id: " + child.attributeValue("id"));

            //未知子元素名情況下
           List<Element> elementList = child.elements();
           for (Element ele : elementList) {
            System.out.println(ele.getName() + ": " + ele.getText());
           }
           System.out.println();

            //已知子元素名的情況下
           // System.out.println("title" + child.elementText("title"));
           // System.out.println("author" + child.elementText("author"));

            System.out.println();
        }
    }*/
}

2.生成XML文檔

package cnslp.dom4j.com;
import org.dom4j.*;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.XMLWriter;

import java.io.File;
import java.io.FileOutputStream;

/**
 * Created by cnslp on 2017/5/12 0012.
 */
public class OutXML {
    public static void main(String[] args) throws Exception {
        Document doc = DocumentHelper.createDocument();
        //增加根節點
        Element books = doc.addElement("books");
        //增加子元素
        Element book1 = books.addElement("book");
        Element title1 = book1.addElement("title");
        Element author1 = book1.addElement("author");

        Element book2 = books.addElement("book");
        Element title2 = book2.addElement("title");
        Element author2 = book2.addElement("author");

        //為子節點添加屬性
        book1.addAttribute("id", "001");
        //為元素添加內容
        title1.setText("Harry Potter");
        author1.setText("J K. Rowling");

        book2.addAttribute("id", "002");
        title2.setText("Learning XML");
        author2.setText("Erik T. Ray");

        //實例化輸出格式對象
        OutputFormat format = OutputFormat.createPrettyPrint();
        //設置輸出編碼
        format.setEncoding("UTF-8");
        //創建需要寫入的File對象
        File file = new File("D:" + File.separator + "books.xml");
        //生成XMLWriter對象，構造函數中的參數為需要輸出的文件流和格式
        XMLWriter writer = new XMLWriter(new FileOutputStream(file), format);
        //開始寫入，write方法中包含上面創建的Document對象
        writer.write(doc);
    }

}

dom4j解析和生成XML文檔