Create xml in android dom way

<?xml version="1.0" encoding="utf-8"?>
<classes>
	<group name="一年级" num="10">
		<person name="小明" age="7">
			<chinese>语文90</chinese>
			<english>英语80</english>
		</person>
	</group>
</classes>

// 从assets文件夹下获取文件 转换成输入流
//			inStream = this.getResources().getAssets().open(fileName);
//			doc = docBuilder.parse(inStream);
			InputStream fosStream = openFileInput(fileName);
			doc = docBuilder.parse(fosStream);

String[] fileNames = getFilesDir().list();

String fileName = fileNames[0];

private void createXmlFile(){
		
		try {
			DocumentBuilderFactory factory = DocumentBuilderFactory
					.newInstance();
			DocumentBuilder builder = factory.newDocumentBuilder();
			Document doc  = builder.newDocument();
			//创建xml根元素
			Element rootEle = doc.createElement("classes");
			doc.appendChild(rootEle);
			//创建xml二级元素
			Element groupEle = doc.createElement("group");
			groupEle.setAttribute("name", "一年级");
			groupEle.setAttribute("num", "10");
			//创建xml person元素
			Element personEle = doc.createElement("person");
			//personEle 的属性和属性值
			personEle.setAttribute("name", "小明");
			personEle.setAttribute("age", "7");
			//创建personELe的子元素
			Element chinese = doc.createElement("chinese");
			//创建personELe的子元素的值
			chinese.appendChild(doc.createTextNode("语文90"));
			personEle.appendChild(chinese);
			Element english = doc.createElement("english");
			english.appendChild(doc.createTextNode("英语80"));
			personEle.appendChild(english);
			
			groupEle.appendChild(personEle);
			rootEle.appendChild(groupEle);
			
			TransformerFactory tf = TransformerFactory.newInstance();
			Transformer transformer = tf.newTransformer();
			
			DOMSource source = new DOMSource(doc);
			transformer.setOutputProperty(OutputKeys.ENCODING, "utf-8");
			transformer.setOutputProperty(OutputKeys.INDENT, "no");
			//创建文件存放在 /data/data/cn.xxx.xxx(当前包)/files 
			FileOutputStream fos = openFileOutput("Dom.xml", Context.MODE_PRIVATE);
			//创建文件存放在 /data/data/cn.xxx.xxx(当前包)/cache
//			FileOutputStream fos = Op
			PrintWriter pw = new PrintWriter(fos);
			StreamResult result = new StreamResult(pw);
			transformer.transform(source, result);
			
			System.out.println("生成XML文件成功!");
		} catch (ParserConfigurationException e) {
			System.out.println(e.getMessage());
		} catch (TransformerConfigurationException e) {
			System.out.println(e.getMessage());
		} catch (TransformerException e) {
			System.out.println(e.getMessage());
		} catch (FileNotFoundException e) {
			System.out.println(e.getMessage());
		}
		
	}