javaweb dom4j解析xml文档

<?xml version="1.0" encoding="UTF-8"?>

<书架> 
  <书> 
    <书名>java程序设计</书名>  
    <作者>张三</作者>  
    <售价>309元</售价>  
    <售价>45元</售价>  
    <出版社>南京大学出版社</出版社> 
  </书>  
  <书> 
    <书名>C语言程序设计</书名>  
    <作者>李四</作者>  
    <售价>40元</售价>  
    <出版社>北京大学出版社</出版社> 
  </书> 
</书架>

package DOM4J;

import java.io.File;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.OutputStreamWriter;
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;
import org.junit.Test;

public class Dom4jDemo {
	@Test
	//用dom4j读取xml文档
	public void read() throws Exception {
		//获得DOCUMENT对象
		SAXReader reader = new SAXReader();
		//获取需要解析文档的路径
		Document document = reader.read(new File("src/book.xml"));
		Element root = document.getRootElement();
		List list = root.elements("书");
		String bookname = ((Element) list.get(1)).element("书名").getText();
		System.out.println(bookname);
	}
	@Test
	//用dom4j添加节点
	public void add() throws Exception {
		//获得DOCUMENT对象
		SAXReader reader = new SAXReader();
		//获取需要解析文档的路径
		Document document = reader.read(new File("src/book.xml"));
		Element root = document.getRootElement();
		List list = root.elements("书");
		((Element) list.get(1)).addElement("出版社").setText("北京大学出版社");
		//更新内存
//		OutputFormat format=OutputFormat.createCompactFormat();//紧凑xml内容
		OutputFormat format=OutputFormat.createPrettyPrint();//漂亮xml内容
		format.setEncoding("UTF-8");
		
		XMLWriter writer = new XMLWriter(new FileOutputStream("src/book.xml"),format);
		writer.write(document);
		writer.close();
	}
	
	@Test
	//用dom4j在指点位置添加节点
		public void add1() throws Exception {
			//获得DOCUMENT对象
			SAXReader reader = new SAXReader();
			//获取需要解析文档的路径
			Document document = reader.read(new File("src/book.xml"));
			Element root = document.getRootElement().element("书");
			List<Element> list =root.elements();
			Element price=DocumentHelper.createElement("售价");
			price.setText("309元");
			list.add(2, price);
			//更新内存
//			OutputFormat format=OutputFormat.createCompactFormat();//紧凑xml内容
			OutputFormat format=OutputFormat.createPrettyPrint();//漂亮xml内容
			format.setEncoding("UTF-8");
			//使用文件输入流
			XMLWriter writer = new XMLWriter(new FileOutputStream("src/book.xml"),format);
			writer.write(document);
			writer.close();
		}
	@Test
	//用dom4j在指点位置添加节点
		public void delete() throws Exception {
			//获得DOCUMENT对象
			SAXReader reader = new SAXReader();
			//获取需要解析文档的路径
			Document document = reader.read(new File("src/book.xml"));
			Element root = document.getRootElement().element("书");
			List<Element> list =root.elements();
			for (Element element : list) {
				System.out.println(element.getName());
				if(element.getName()=="出版社"){
					element.getParent().remove(element);
				}
			}		
			//更新内存
//			OutputFormat format=OutputFormat.createCompactFormat();//紧凑xml内容
			OutputFormat format=OutputFormat.createPrettyPrint();//漂亮xml内容
			format.setEncoding("UTF-8");
			//使用文件输入流
			XMLWriter writer = new XMLWriter(new FileOutputStream("src/book.xml"),format);
			writer.write(document);
			writer.close();
		}
	
	@Test
	//用dom4j更新数据
		public void update() throws Exception {
			//获得DOCUMENT对象
			SAXReader reader = new SAXReader();
			//获取需要解析文档的路径
			Document document = reader.read(new File("src/book.xml"));
			Element root = document.getRootElement().element("书");
			List<Element> list =root.elements();
			for (Element element : list) {
				if(element.getName()=="出版社"){
					element.setText("南京大学出版社");
				}
			}		
			//更新内存
//			OutputFormat format=OutputFormat.createCompactFormat();//紧凑xml内容
			OutputFormat format=OutputFormat.createPrettyPrint();//漂亮xml内容
			format.setEncoding("UTF-8");
			//使用文件输入流
			XMLWriter writer = new XMLWriter(new FileOutputStream("src/book.xml"),format);
			writer.write(document);
			writer.close();
		}
}