dom4j增删改查

     //dom4j添加内容，在第一本书上指定位置添加售价  更改保存所有孩子list集合的顺序
     @Test
     public void add1() throws Exception{
         //读
         SAXReader reader = new SAXReader();
         Document document = reader.read(new File("src/book.xml"));

         //添加
         Element book = document.getRootElement().element("书");
         List list = book.elements();//[书名、作者、售价]
         Element price = DocumentHelper.createElement("售价");
         price.setText("309");
         list.add(2,price);

         //输出
         OutputFormat format = OutputFormat.createPrettyPrint();
         format.setEncoding("UTF-8");
         XMLWriter writer = new XMLWriter(new FileOutputStream("src/book.xml"),format);
         writer.write(document);
         writer.close();

     }
     @Test
     public void deleat() throws Exception{
         //读
         SAXReader reader = new SAXReader();
         Document document = reader.read(new File("src/book.xml"));

         //删除
         Element price = document.getRootElement().element("书").element("售价");
         price.getParent().remove(price);

         //输出
         OutputFormat format = OutputFormat.createPrettyPrint();
         format.setEncoding("UTF-8");
         XMLWriter writer = new XMLWriter(new FileOutputStream("src/book.xml"),format);
         writer.write(document);
         writer.close();

     }