dom4j解析xml文档

有一个xml文档

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

<书架> 
  <书> 
    <书名 name="xxxx">java web</书名>  
    <作者>张大</作者>  
    <价格>102</价格>  
    <评价>well</评价> 
  </书>  
  <书> 
    <书名>spring</书名>  
    <作者>呜呜</作者>  
    <价格>55</价格> 
  </书> 
</书架>

读取文档的内容（第二本书的书名）

	public void read() throws DocumentException{
		SAXReader reader = new SAXReader();
	    Document document = reader.read(new File("src/book.xml"));
	    
	    Element root = document.getRootElement();
	    Element book = (Element) root.elements("书").get(1);
	    String value = book.element("书名").getText();
	    System.out.println(value);
	}

读取文档的属性（name中的属性）

	public void readAtrr() throws DocumentException{
		SAXReader reader = new SAXReader();
	    Document document = reader.read(new File("src/book.xml"));
	    
	    Element root = document.getRootElement();
	    Element book = (Element) root.elements("书").get(0);
	    String value = book.element("书名").attribute("name").getValue();
	    System.out.println(value);

	}

在默认位子添加一个评价

	public void add() throws Exception{
		SAXReader reader = new SAXReader();
	    Document document = reader.read(new File("src/book.xml"));
	    
	    Element book = document.getRootElement().element("书");
	    book.addElement("评价").setText("well");
	    
	    //更新到xml，注意乱码问题
	    XMLWriter writer = new XMLWriter(
	    		new OutputStreamWriter(new FileOutputStream("src/book.xml"), "utf-8")
	    );
	    writer.write( document );  //UTF-8
        writer.close();
	}

在指定位子添加（价格上）

	public void add3() throws Exception{
		SAXReader reader = new SAXReader();
	    Document document = reader.read(new File("src/book.xml"));
	    
	    Element book = document.getRootElement().element("书");
	    List list = book.elements();
	    
	    //创建要加入的节点
	    Element evaluation = DocumentHelper.createElement("评价");
	    evaluation.setText("good,good");
	    
	    list.add(2, evaluation);
	    
	    //更新到xml，注意乱码问题
	    OutputFormat format = OutputFormat.createPrettyPrint();
	    format.setEncoding("utf-8");//和xml文档一致
	    XMLWriter writer = new XMLWriter(new FileOutputStream("src/book.xml"),format );
	    
	    writer.write( document );  //UTF-8
        writer.close();
	}

删除一个评价

	public void delete() throws Exception{
		SAXReader reader = new SAXReader();
	    Document document = reader.read(new File("src/book.xml"));
	    
	    List list = document.getRootElement().element("书").elements("评价");
	    list.remove(0);
	    
	    //更新到xml，注意乱码问题
	    OutputFormat format = OutputFormat.createPrettyPrint();
	    format.setEncoding("utf-8");//和xml文档一致
	    XMLWriter writer = new XMLWriter(new FileOutputStream("src/book.xml"),format );
	    
	    writer.write( document );  //UTF-8
        writer.close();
	}

更改节点

	public void update() throws Exception{
		SAXReader reader = new SAXReader();
	    Document document = reader.read(new File("src/book.xml"));
	    
	    Element book = (Element) document.getRootElement().elements("书").get(1);
	    book.element("作者").setText("哈哈！");
	    
	    OutputFormat format = OutputFormat.createPrettyPrint();
	    format.setEncoding("utf-8");//和xml文档一致
	    XMLWriter writer = new XMLWriter(new FileOutputStream("src/book.xml"),format );
	    
	    writer.write( document );  //UTF-8
        writer.close();
	    
	}