读取xml文件

简单的一个xml文件

<?xml version="1.0" encoding="UTF-8"?>
<书架>
     <书>
        <书名 name="wang">web实战开发</书名>
        <作者>王国辉</作者>
        <售价>100</售价>
     </书>
     <书>
        <书名>java核心技术</书名>
        <作者>Gary.Cornnell</作者>
        <售价>100</售价>
     </书>
</书架>

然后用java写程序来读取该文件

import java.io.FileOutputStream;
import java.io.IOException;

//所有相关的包都是org.w3c.dom
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

import org.junit.Test;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

public class Factory {
	/*public static void main(String[] args) throws Exception
	{
		//创建工厂
		DocumentBuilderFactory factory=DocumentBuilderFactory.newInstance();
		//创建dom解析器
		DocumentBuilder builder=factory.newDocumentBuilder();
		//解析xml文档，得到代表文档的document
		Document document=builder.parse("src/book.xml");
	}
	*/
	@Test
	public void read() throws Exception
	{
		DocumentBuilderFactory factory=DocumentBuilderFactory.newInstance();
		DocumentBuilder builder=factory.newDocumentBuilder();
		Document document=builder.parse("G:\\JAVA  TEST\\Test\\src\\test1\\book.xml");
		
		NodeList list=document.getElementsByTagName("书名");
		Node node=list.item(1);
		String content=node.getTextContent();
		System.out.println(content);
	}
	@Test
	public void read1() throws Exception
	{
		DocumentBuilderFactory factory=DocumentBuilderFactory.newInstance();
		DocumentBuilder builder=factory.newDocumentBuilder();
		Document document=builder.parse("G:\\JAVA  TEST\\Test\\src\\test1\\book.xml");
		
		Node node=document.getElementsByTagName("书架").item(0);
		
		root(node);
	}
	private void root(Node node)            //私有方法才能运行成功
	{
		if(node instanceof Element)
		{
			System.out.println(node.getNodeName());
		}
		NodeList list=node.getChildNodes();
		for(int i=0;i<list.getLength();i++)
		{
			Node child=list.item(i);
			root(child);
		}
	}
	@Test
	public void read3() throws Exception
	{
		DocumentBuilderFactory factory=DocumentBuilderFactory.newInstance();
		DocumentBuilder builder=factory.newDocumentBuilder();
		Document document=builder.parse("G:\\JAVA  TEST\\Test\\src\\test1\\book.xml");
		
		Element bookname=(Element)document.getElementsByTagName("书名").item(0);
		//在知道类型的情况下转化
		String value=bookname.getAttribute("name");
		System.out.println(value);
	}
	@Test
	public void read4() throws Exception
	{
		DocumentBuilderFactory factory=DocumentBuilderFactory.newInstance();
		DocumentBuilder Builder=factory.newDocumentBuilder();
		Document document=Builder.parse("G:\\JAVA  TEST\\Test\\src\\test1\\book.xml");
		//创建节点
		Element Class=document.createElement("类别");
		Class.setTextContent("it");
		//把该元素添加到节点
		//获得参考节点
		Element refnode=(Element)document.getElementsByTagName("售价").item(0);
		
		Element book=(Element)document.getElementsByTagName("书").item(0);
		//插入到指定位置
		book.insertBefore(Class, refnode);
		//把更新内容保存的xml文档
		TransformerFactory transformerfactory=TransformerFactory.newInstance();
		Transformer transformer=transformerfactory.newTransformer();
		transformer.transform(new DOMSource(document),new StreamResult(new FileOutputStream("G:\\JAVA  TEST\\Test\\src\\test1\\book.xml")));
	
	}
}