<?xml version="1.0" encoding="UTF-8"?>
 
<书架> 
  <书> 
    <书名>Java就业培训教程</书名>  
    <作者>张孝祥</作者>  
    <售价>39.00元</售价> 
  </书>  
  <书> 
    <书名>JavaScript网页开发</书名>  
    <作者>张孝祥</作者>  
    <售价>28.00元</售价> 
  </书> 
</书架>

package com.itheima.sax;
 
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
 
import org.xml.sax.Attributes;
import org.xml.sax.ContentHandler;
import org.xml.sax.Locator;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.DefaultHandler;
 
 
public class SaxDemo1 {
	public static void main(String[] args) throws Exception {
		//1.获取解析器工厂
		SAXParserFactory factory = SAXParserFactory.newInstance();
		//2.通过工厂获取sax解析器
		SAXParser parser = factory.newSAXParser();
		//3.获取读取器
		XMLReader reader = parser.getXMLReader();
		//4.注册事件处理器
		reader.setContentHandler(new MyContentHandler2() );
		//5.解析xml
		reader.parse("book.xml");
		
		
	}
}
 
//适配器设计模式
class MyContentHandler2 extends DefaultHandler{
	private String eleName = null;
	private int count = 0;
	@Override
	public void startElement(String uri,String localName,String name,Attributes attributes) throws SAXException {
		this.eleName = name;
	}
	
	@Override
	public void characters(char[] ch,int start,int length)
			throws SAXException {
		if("书名".equals(eleName) && ++count==2){
			System.out.println(new String(ch,start,length));
		}
	}
	
	@Override
	public void endElement(String uri,String name)
			throws SAXException {
		eleName = null;
	}
	
}
 
 
 
 
class MyContentHandler implements ContentHandler{
 
	public void startDocument() throws SAXException {
		System.out.println("文档解析开始了.......");
	}
	
	public void startElement(String uri,Attributes atts) throws SAXException {
		System.out.println("发现了开始标签,"+name);
	}
	
	public void characters(char[] ch,int length)
		throws SAXException {
		System.out.println(new String(ch,length));
	}
	
	public void endElement(String uri,String name)
		throws SAXException {
		System.out.println("发现结束标签,"+name);
	}
 
	
	public void endDocument() throws SAXException {
		System.out.println("文档解析结束了.......");
	}
	
	
	
	
	
	
	
	
	
	public void endPrefixMapping(String prefix) throws SAXException {
		// TODO Auto-generated method stub
		
	}
 
	public void ignorableWhitespace(char[] ch,int length)
			throws SAXException {
		// TODO Auto-generated method stub
		
	}
 
	public void processingInstruction(String target,String data)
			throws SAXException {
		// TODO Auto-generated method stub
		
	}
 
	public void setDocumentLocator(Locator locator) {
		// TODO Auto-generated method stub
		
	}
 
	public void skippedEntity(String name) throws SAXException {
		// TODO Auto-generated method stub
		
	}
 
	
 
	
 
	public void startPrefixMapping(String prefix,String uri)
			throws SAXException {
		// TODO Auto-generated method stub
		
	}
	
}

//1.获取解析器工厂
		SAXParserFactory factory = SAXParserFactory.newInstance();
		//2.通过工厂获取sax解析器
		SAXParser parser = factory.newSAXParser();
		//3.获取读取器
		XMLReader reader = parser.getXMLReader();
		//4.注册事件处理器
		reader.setContentHandler(new MyContentHandler2() );
		//5.解析xml
		reader.parse("book.xml");

package com.itheima.dom4j;
 
import org.dom4j.Document;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;
 
public class Dom4jDemo1 {
	public static void main(String[] args) throws Exception {
		//1.获取解析器
		SAXReader reader = new SAXReader();
		//2.解析xml获取代表整个文档的dom对象
		Document dom = reader.read("book.xml");
		//3.获取根节点
		Element root = dom.getRootElement();
		//4.获取书名进行打印
		String bookName = root.element("书").element("书名").getText();
		System.out.println(bookName);
	}
}

SAXReader reader = new SAXReader();
Document dom = reader.read("book.xml");
Element root = dom.getRootElement();

package com.itheima.dom4j;
 
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.io.OutputFormat;
import org.dom4j.io.SAXReader;
import org.dom4j.io.XMLWriter;
import org.junit.Test;
 
public class Demo4jDemo2 {
	@Test
	public void attr() throws Exception{
		SAXReader reader = new SAXReader();
		Document dom = reader.read("book.xml");
		Element root = dom.getRootElement();
		
		Element bookEle = root.element("书");
		//bookEle.addAttribute("出版社","传智出版社");
		//String str = bookEle.attributeValue("出版社");
		//System.out.println(str);
		Attribute attr = bookEle.attribute("出版社");
	    attr.getParent().remove(attr);
		
		XMLWriter writer = new XMLWriter(new FileOutputStream("book.xml"),OutputFormat.createPrettyPrint());
		writer.write(dom);
		writer.close();
	}
	
	@Test
	public void del() throws Exception{
		SAXReader reader = new SAXReader();
		Document dom = reader.read("book.xml");
		Element root = dom.getRootElement();
		
		Element price2Ele = root.element("书").element("特价");
		price2Ele.getParent().remove(price2Ele);
 
		XMLWriter writer = new XMLWriter(new FileOutputStream("book.xml"),OutputFormat.createPrettyPrint());
		writer.write(dom);
		writer.close();
	}
	
	@Test
	public void update()throws Exception{
		SAXReader reader = new SAXReader();
		Document dom = reader.read("book.xml");
		Element root = dom.getRootElement();
		
		root.element("书").element("特价").setText("4.0元");
		
		XMLWriter writer = new XMLWriter(new FileOutputStream("book.xml"),OutputFormat.createPrettyPrint());
		writer.write(dom);
		writer.close();
	}
	
	@Test
	public void add()throws Exception{
		SAXReader reader = new SAXReader();
		Document dom = reader.read("book.xml");
		Element root = dom.getRootElement();
		//凭空创建<特价>节点,设置标签体
		Element price2Ele = DocumentHelper.createElement("特价");
		price2Ele.setText("40.0元");
		//获取父标签<书>将特价节点挂载上去
		Element bookEle = root.element("书");
		bookEle.add(price2Ele);
		
		//将内存中的dom树会写到xml文件中,从而使xml中的数据进行更新
//		FileWriter writer = new FileWriter("book.xml");
//		dom.write(writer);
//		writer.flush();
//		writer.close();
		//加了一个OutputFormat.createPrettyPrint()格式转化器，作用是让让新增节点对齐
		XMLWriter writer = new XMLWriter(new FileOutputStream("book.xml"),OutputFormat.createPrettyPrint());
		writer.write(dom);
		writer.close();
	}
	
	@Test
	public void find() throws Exception{
		SAXReader reader = new SAXReader();
		Document dom = reader.read("book.xml");
		Element root = dom.getRootElement();
		
		List<Element> list =  root.elements();
		Element book2Ele = list.get(1);
		System.out.println(book2Ele.element("书名").getText());
		
	}
}