使用dom4j其它的API

import java.io.File;
import java.io.FileOutputStream;
import java.io.OutputStream;
import java.util.List;

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

//使用dom4j其它的API
public class Demo4 {
    public static void main(String[] args) throws Exception {

        //String->XML
        String text = "这是根元素";
        Document document = DocumentHelper.parseText(text);
        OutputFormat format = OutputFormat.createPrettyPrint();
        OutputStream os = new FileOutputStream("src/day2/domx/stringcar.xml");
        XMLWriter xmlWriter = new XMLWriter(os,format);
        xmlWriter.write(document);
        xmlWriter.close();

        /*创建空XML文件*/
        Document document = DocumentHelper.createDocument();
        document.addElement("root").setText("这是根元素");
        OutputFormat format = OutputFormat.createPrettyPrint();
        OutputStream os = new FileOutputStream("src/day2/domx/stringcar.xml");
        XMLWriter xmlWriter = new XMLWriter(os,format);
        xmlWriter.write(document);
        xmlWriter.close();

        /*指定插入次序，默认插入到最后*/
        SAXReader saxReader = new SAXReader();
        Document document = saxReader.read(new File("src/day2/domx/stringcar.xml"));
        List elementList = document.getRootElement().elements();
        Element newCarElement = DocumentHelper.createElement("汽车");
        newCarElement.setText("这是我的汽车");
        elementList.add(1,newCarElement);
        OutputFormat format = OutputFormat.createPrettyPrint();
        OutputStream os = new FileOutputStream("src/day2/domx/stringcar.xml");
        XMLWriter xmlWriter = new XMLWriter(os,format);
        xmlWriter.write(document);
        xmlWriter.close();

        //XML->String
        SAXReader saxReader = new SAXReader();
        Document document = saxReader.read(new File("src/day2/domx/stringcar.xml"));
        Element rootElement = document.getRootElement();
        Element firstCarElement = (Element) rootElement.elements().get(0);
        String xml = firstCarElement.asXML();
        System.out.println(xml);
    }
}