dom4j是由JDOM开发团队分裂后开发出来的包；在hibernate、JAXM中都使用了dom4j；

性能来说：Dom4j>JDom>JAXP;

DocumentHelper类中有：

(1)Document document = DocumentHelper.createDocument(); //创建一个document对象，通常用于新建一个xml文档

(2)Element element = DocumentHelper.createElement(); //创建一个element对象，即创建一个标签

(3)Document document = DocumentHelper.parseText(String xml); //将xml字符串转换成以document为根节点的DOM树

 

SAXReader类中有：

(1)SAXReader reader = new SAXReader();

(2)Document document  = reader.read(new File("1.xml")); //读取并解析1.xml文档，并返回document

 

Document类中有：

(1)String text = document.asXML(Document); //将一颗DOM树转为XML字符串

(2)Element root = document.getRootElement(); //获得根节点

 

Element中有：

(1)Element newelem = elem.addElement("child"); //加入名为child的子标签，并返回此element

(2)newelem.addAttribute("name","value"); //标签添加一个属性

(3)newelem.addText("xxxx"); //为标签添加一个标签值

(4)newelem.getText(); //获得标签的标签值

(5)String value = newelem.attributeValue("name"); //获得标签的属性值

(6)Iterator iter = newelem.attributeIterator() ; //标签的属性迭代器

(7)List childs = newelem.elements(); //获得标签的全部子元素

(8)Element child = newelem.element("name"); //获得标签的子标签中的多个标签中的第一个元素

(9)List childs = newelem.elements("name"); //获得标签的子标签中的全部标签

(10)newelem.remove(elem); //删除elem标签

 

XMLWriter类中有：

(1)XMLWriter writer = new XMLWriter(OutputStream out,OutputFormat format);

(2)writer.write(document); //输出document

(3)writer.close(); //关闭XMLWriter流

 

OutputFormat类中有：

(1)OutputFormat format = OutputFormat.createPrettyFormat(); //输出时排版整齐

(2)OutputFormat format = OutputFormat.createCompactFormat(); //输出时排版紧实

(3)format.setEncoding("UTF-8"); //设置中的encoding属性，默认为UTF-8

 

Attribute类中有：

(1)attr.setValue("value"); //设置属性

(2)String value = attr.getValue();

三、dom4j中的CRUD

 

1.Create

 

创建一个文档：

 private static void create() throws Exception {    Document document = DocumentHelper.createDocument();    Element person = DocumentHelper.createElement("person");    document.add(person);    Element name = person.addElement("name").addAttribute("a", "x").addText("xiazdong");    Element age = person.addElement("age").addText("20");    OutputFormat format = OutputFormat.createPrettyPrint();    format.setEncoding("utf-8");    XMLWriter writer = new XMLWriter(new FileOutputStream("output.xml"),format);    writer.write(document);    writer.close();   }

插入：

private static void insert(Document document) throws Exception {   Element root = document.getRootElement();   List list =  root.elements("person");   Element person = (Element)list.get(1);   Element tmpElement = person.addElement("tmpChild");   tmpElement.setText("tmp");    //添加标签值   tmpElement.addAttribute("tmpname", "tmpvalue"); //添加属性   Element tmp2 = DocumentHelper.createElement("tmpChild2");//创建一个element   tmp2.setText("tmp2");   list.add(1,tmp2); //在指定位置添加元素   XMLWriter writer = new XMLWriter(new FileOutputStream("1.xml"));   writer.write(document);   writer.close();   }

2.Read

 

private static void read(Document document) throws Exception{   Element root = document.getRootElement();   Element person = (Element) root.elements("person").get(1);   String value = person.element("name").getText();   String attri = person.element("name").attributeValue("a");   System.out.println(value);   System.out.println(attri);  }

3.Update

 

private static void update(Document document) throws Exception{   Element root = document.getRootElement();   Element name = root.element("person").element("name");   name.setText("xiazdong");    //更新标签值   name.attribute("a").setValue("bb");  //更新属性值   OutputFormat format = OutputFormat.createPrettyPrint();   format.setEncoding("utf-8");   XMLWriter writer = new XMLWriter(new FileOutputStream("1.xml"),format);   writer.write(document);   writer.close();  }

4.Delete

private static void delete(Document document) throws Exception {   Element root = document.getRootElement();   Element name = root.element("person").element("name");   name.remove(name.attribute("a"));  //删除attribute   name.getParent().remove(name);   //删除element   OutputFormat format = OutputFormat.createPrettyPrint();   format.setEncoding("utf-8");   XMLWriter writer = new XMLWriter(new FileOutputStream("1.xml"),format);   writer.write(document);   writer.close();  }

四、乱码问题

 

解决方法：

format.setEncoding("UTF-8");

并且用字节流输出

 

 转自：http://blog.csdn.net/xiazdong/article/details/7294109