操作前,记得加载dom4j的jar文件

示例代码如下

package web_day04;



import java.io.FileOutputStream;

import java.io.FileWriter;

import java.io.IOException;

import java.util.Iterator;



import org.dom4j.*;

import org.dom4j.io.OutputFormat;

import org.dom4j.io.SAXReader;

import org.dom4j.io.XMLWriter;

import org.junit.Test;



import java.util.List;



/*

 * 读取节点

 * 读取属性

 * 添加节点

 * 删除节点

 * 更新节点

 * 打印元素节点

 * 

 */

 



public class Dom4jExercises {

	//读取节点文本

	@Test

	public void readNodeText() throws DocumentException{

		//获得代表xml文件的document对象

		Document document = getDomDocment();

		Element rootElement = document.getRootElement();

		Element firstBookElement = rootElement.element("书");

		Element firstBookNameElement = firstBookElement.element("书名");

		String bookName = firstBookNameElement.getText();

		System.out.println(bookName);

		

	}

	

	//读取所有属性的值

	@Test

	public void testReadAttribute() throws DocumentException{

		Document document = getDomDocment();

		//获得第二本书的属性

		Element rootElement = document.getRootElement();

		List listElement = rootElement.elements();

		

		for(int i=0;i<listElement.size();i++)

		{

			//获取子元素的属性

			//listElement.get(i).toString();

			//System.out.println(listElement.get(i).toString());

			Element nodeElement = (Element)listElement.get(i);

			String attrStr =  nodeElement.attributeValue("出版社");

			System.out.println(attrStr);

		}

		

	}

	//添加节点 [第二条加入]

	@Test

	public void addNodeTest() throws IOException, DocumentException{

		Document document = getDomDocment();

		

		//第二条添加一个price

		

		Element rootElement = document.getRootElement();

		List listElement = rootElement.elements();

		Element secondElement = (Element)listElement.get(1);

		

		secondElement.addElement("price").addText("7.8折");

		

		//写会文件

		//document.setXMLEncoding("utf-8");

		

		write(document,"utf-8");

	}

	

	@Test

	public void deleteNode() throws DocumentException, IOException{

		Document document = getDomDocment();

		Element rootElement = document.getRootElement();

		List listElement = rootElement.elements();

		

		Element secondElement = (Element)listElement.get(1);

		secondElement.remove((Element)(secondElement.elements().get(3)));

		

		write(document,"utf-8");

		

		

	}

	

	

	

	private Document getDomDocment() throws DocumentException {

		SAXReader reader = new SAXReader();

        Document document = reader.read("src/book.xml");

        return document;

	}

	

	

	public void write(Document document,String encode) throws IOException {

		



        //注意由于FileWriter 很久没有更新,一致使用的是老版本的

        //FileWriter始终使用的是当前系统相关的编码,跟自己设置的编码无关

        //原则写文件,不要使用FileWriter

		

		

		OutputFormat format = new OutputFormat();

		

		if (null != encode)  

        {  

            format.setEncoding(encode.toUpperCase());  

        }  

		

        // lets write to a file

		/*

        XMLWriter writer = new XMLWriter(

            new FileWriter( "src/book.xml" ),format

        );

        */

		XMLWriter writer = new XMLWriter(

				new FileOutputStream("src/book.xml"),format

				);

        

        writer.write( document );

        writer.close();

    }

}