1     //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 2     @Test 3     public void add1() throws Exception{ 4         //读 5         SAXReader reader = new SAXReader(); 6         Document document = reader.read(new File("src/book.xml")); 7  8         //添加 9         Element book = document.getRootElement().element("书");10         List list = book.elements();//[书名、作者、售价]11         Element price = DocumentHelper.createElement("售价");12         price.setText("309");    13         list.add(2,price);14         15         //输出16         OutputFormat format = OutputFormat.createPrettyPrint();17         format.setEncoding("UTF-8");18         XMLWriter writer = new XMLWriter(new FileOutputStream("src/book.xml"),format);19         writer.write(document);20         writer.close();21 22     }23     @Test24     public void deleat() throws Exception{25         //读26         SAXReader reader = new SAXReader();27         Document document = reader.read(new File("src/book.xml"));28 29         //删除30         Element price = document.getRootElement().element("书").element("售价");31         price.getParent().remove(price);32         33         //输出34         OutputFormat format = OutputFormat.createPrettyPrint();35         format.setEncoding("UTF-8");36         XMLWriter writer = new XMLWriter(new FileOutputStream("src/book.xml"),format);37         writer.write(document);38         writer.close();39 40     }