DOM4J解析XML

 DOM4J解析XML文件是DOM解析中最好用的一种方法，只要在工程目录下导入dom4j-1.6.1.jar就行了 

package cn.moving.parseXml;

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

import org.dom4j.Attribute;
import org.dom4j.Document;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
import org.dom4j.Node;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.SAXReader;
import org.dom4j.io.XMLWriter;
import org.junit.Test;


public class Dom4jParse {

	@Test
	public void read() throws Exception {
		SAXReader reader = new SAXReader();
		Document document = reader.read(new File(
				"src/cn/moving/parseXml/book.xml"));
		Element books = document.getRootElement();
		Element e = (Element) books.elements().get(0);
		Element bookName = e.element("书名");
		System.out.println(bookName.getText());
		Attribute attr = bookName.attribute("name");
		System.out.println(attr.getText());

	}

	@Test
	public void add() throws Exception {
		SAXReader reader = new SAXReader();
		Document document = reader.read("src/cn/moving/parseXml/book.xml");
		Element book = (Element) document.getRootElement().element("书");
		book.addElement("出版社").setText("人民邮电出版社");
		OutputFormat format = OutputFormat.createCompactFormat();
		// OutputFormat format = new OutputFormat();
		format.setEncoding("UTF-8");
		XMLWriter writer = new XMLWriter(new FileOutputStream(
				"src/cn/moving/parseXml/outbook2.xml"));
		// XMLWriter writer = new XMLWriter(new
		// FileOutputStream("src/cn/moving/parseXml/outbook2.xml"), format);
		writer.write(document);
		writer.close();
	}
	
	@Test
	//往指定位置添加元素
	public void addAppoint() throws Exception {
		SAXReader reader = new SAXReader();
		Document document = reader.read("src/cn/moving/parseXml/book.xml");
		Element book = (Element) document.getRootElement().element("书");
		List list = book.elements();//[书名，作者，价格]
		Element e = DocumentHelper.createElement("折扣");
		e.setText("7折");
		list.add(2,e);
		OutputFormat format = OutputFormat.createCompactFormat();
		// OutputFormat format = new OutputFormat();
		format.setEncoding("UTF-8");

		XMLWriter writer = new XMLWriter(new FileOutputStream(
				"src/cn/moving/parseXml/outbook2.xml"));		

                //漂亮格式输出

		// XMLWriter writer = new XMLWriter(new FileOutputStream("src/cn/moving/parseXml/outbook2.xml"), format);
		writer.write(document);
		writer.close();
	}
	
	@Test
	// 删除节点<售价>10</售价>
	public void delete() throws Exception {
		SAXReader reader = new SAXReader();
		Document document  = reader.read("src/cn/moving/parseXml/book.xml");
		Element element = document.getRootElement().element("书").element("售价");
		element.getParent().remove(element);
		XMLWriter writer = new XMLWriter(new FileOutputStream("src/cn/moving/parseXml/book.xml"));
		writer.write(document);
		writer.close();
	

	}

	@Test
	// 更新售价
	public void update() throws Exception {

		SAXReader reader = new SAXReader();
		Document document  = reader.read("src/cn/moving/parseXml/book.xml");
		Element element = document.getRootElement().element("书").element("售价");
		element.setText("59");
		XMLWriter writer = new XMLWriter(new FileOutputStream("src/cn/moving/parseXml/book.xml"));
		writer.write(document);
		writer.close();		
	}
	
	@Test
	//Powerful Navigation with XPath
	public void xpath() throws Exception{
		SAXReader reader = new SAXReader();
		Document document = reader.read(new File("src/cn/moving/parseXml/book.xml"));
		String value = document.selectSingleNode("//作者").getText();
		Node node = document.selectSingleNode("//书名[@aa='bbb']");
		String bookName = document.selectSingleNode("//书名[@aa='bbb']").getText();
		String attrValue = node.valueOf("@aa");
		System.out.println(value);
		System.out.println(attrValue);
		System.out.println(bookName);
	}
}