java 使用 dom 和 dom4j 读写xml

最近闲着没事，简单整理一下java读写xml的方法，以前也就是匆匆忙忙的使用，没有认真的思考过，本人菜鸟，希望各位老鸟指正！

本来想总结一下常用的读写xml的四个方法，为了写程序方便，定义了接口，事与愿违，有时间以后补上吧！
定义接口如下：

public interface ParserXmlInterface
{
	//创建xml
	public void createXml(String path);
	//解析xml
	public void parserXml(String fileName);
	//为dom4j xpath定义
	public void xpathDom4j(String path);
}

1.Dom读写xml方法

public class DomParaserXmlImpl
		implements ParserXmlInterface
{
	private Document document;

	// 实现接口生成xml方法
	public void createXml(String path)
	{
		// 初始化DOM
		this.initDocument();

		// 创建元素，并添加节点
		Element root = this.document.createElement("employess");
		this.document.appendChild(root);
		Element employee = this.document.createElement("employee");

		Element name = this.document.createElement("name");
		name.appendChild(this.document.createTextNode("gshzhou"));
		employee.appendChild(name);

		Element sex = this.document.createElement("sex");
		sex.appendChild(this.document.createTextNode("male"));
		employee.appendChild(sex);

		Element age = this.document.createElement("age");
		age.appendChild(this.document.createTextNode("25"));

		employee.appendChild(age);
		root.appendChild(employee);

		try
		{
			// 确定要创建的哪一个 Factory 实现被命名为
			TransformerFactory transFactory = TransformerFactory.newInstance();
			// 将原树转换为结果树。可以在转换之间保留参数和输出属性
			Transformer tf = transFactory.newTransformer();
			// 创建带有DOM节点的新输入源
			DOMSource domSource = new DOMSource(document);
			// 设置转换中实际的输出属性。
			tf.setOutputProperty(OutputKeys.INDENT, "yes");
			// java.io 向文本输出流打印对象的格式化表示形式。
			PrintWriter writer = new PrintWriter(new FileOutputStream(path));
			// 从字节流构造充当结果的持有者
			StreamResult result = new StreamResult(writer);
			// 讲xml转换为目标结果。
			tf.transform(domSource, result);

			System.out.println("xml生成成功");
		}
		catch (Exception e)
		{
			System.out.println("生成xml时异常：" + e.getMessage());
		}
	}

	// 实现接口解析xml
	public void parserXml(String fileName)
	{
		DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
		try
		{
			DocumentBuilder db = factory.newDocumentBuilder();
			document = db.parse(fileName);
			NodeList employees = document.getChildNodes();
			for( int i = 0; i < employees.getLength(); i++)
			{
				Node employee = employees.item(i);
				NodeList employeeInfo = employee.getChildNodes();
				for( int j = 0; j < employeeInfo.getLength(); j++)
				{
					Node node = employeeInfo.item(j);
					NodeList employeeMate = node.getChildNodes();
					for( int k = 0; k < employeeMate.getLength(); k++)
					{
						System.out.println(employeeMate.item(k).getNodeName()
								+ ":" + employeeMate.item(k).getTextContent());
					}
				}
			}
			System.out.println("DOM 解析完毕");
		}
		catch (Exception e)
		{
			e.printStackTrace();
			System.out.println("解析xml异常:" + e.getMessage());
		}
	}

	// 初始化dom
	private void initDocument()
	{
		try
		{
			DocumentBuilderFactory factory = DocumentBuilderFactory
					.newInstance();
			DocumentBuilder builder = factory.newDocumentBuilder();
			this.document = builder.newDocument();
		}
		catch (ParserConfigurationException e)
		{
			System.out.println("初始化DOM异常>");
		}
	}
	
	//方法是为Dom4j定义的接口，用xpath很方便 的找到节点的属性以及值。
	public void xpathDom4j(String path)
	{
		
	}
}

2. dom4j 读写xml以及xpath的简单使用。

public class Dom4jParaserXmlImpl
		implements ParserXmlInterface
{
	//dom4j生成xml
	public void createXml(String path)
	{
		Document document = DocumentHelper.createDocument();
		Element employees = document.addElement("employees");
		
		//第一个员工信息
		Element employee = employees.addElement("employee");
		employee.addAttribute("id", "gshzhou");
		
		Element name = employee.addElement("name");
		name.setText("gshzhou");
		Element sex = employee.addElement("sex");
		sex.setText("male");
		Element age = employee.addElement("age");
		age.setText("25");
		
		//第二个员工信息
		Element employee2 = employees.addElement("employee");
		employee2.addAttribute("id", "mingr");
		Element name2 = employee2.addElement("name");
		name2.setText("mingr");
		Element sex2 = employee2.addElement("sex");
		sex2.setText("male");
		Element age2 = employee2.addElement("age");
		age2.setText("30");
		
		try
		{
			Writer fileWrite = new FileWriter(path);
			XMLWriter xmlWrite = new XMLWriter(fileWrite);
			xmlWrite.write(document);
			xmlWrite.close();
			System.out.println("Dom4j生成xml成功。");
		}
		catch (IOException e)
		{
			System.out.println("Dom4j生成xml异常。" + e.getMessage());
		}
		
	}

	//dom4j解析xml
	public void parserXml(String fileName)
	{
		File inputXml = new File(fileName);
		SAXReader saxReader = new SAXReader();
		
		try
		{
			Document document = saxReader.read(inputXml);
			Element employees = document.getRootElement();
			for(Iterator i = employees.elementIterator(); i.hasNext(); )
			{
				Element employee = (Element)i.next();
				for(Iterator j = employee.elementIterator(); j.hasNext(); )
				{
					Element node = (Element)j.next();
					System.out.println(node.getName() + ":" + node.getText());
				}
			}
			System.out.println("Dom4j解析成功.");
		}
		catch (DocumentException e)
		{
			System.out.println("dom4j解析xml异常：" + e.getMessage());
		}
	}
	
	//Dom4j的一个亮点，使用xpath语法查找节点，快
	public void xpathDom4j(String path)
	{
		SAXReader saxReader = new SAXReader();
		try
		{
			Document document = saxReader.read(path);
			Node root = document.selectSingleNode("/employees");
			//Node root = document.getRootElement();
			//取employees下id为gshzhou的节点
			List list = root.selectNodes("employee[@id='gshzhou']");
			System.out.println(list.size());
			for(Object o : list)
			{
				Element e = (Element)o;
				//attributeValue是读取节点的属性值
				System.out.println("Node's attribute -> " + e.attributeValue("id"));
			}
			//取employees下所有的 employee节点
			List list1 = root.selectNodes("employee");
			//取employees节点下的employee节点下的name节点
			List list2 = root.selectNodes("employee[@id='gshzhou']/name");
			System.out.println("Node name -> " + ((Element)list2.get(0)).getName()); //输出子节点名字
			System.out.println("Node value -> "+((Element)list2.get(0)).getText());//输出子节点内容
		}
		catch (DocumentException e)
		{
			e.printStackTrace();
		}
	}
}

说明：Dom4j用到了 dom4j-1.6.1.jar 和 jaxen-1.1-beta-6.jar 都能在下载的dom4j包中找到。

评论

2 楼 free_zhou 2010-06-02  

谢谢 这不是在你的指导下

1 楼 liwanfeng 2010-05-20  

可以！看来学习的还是很快的吗！恭喜恭喜啊！