Java操作XML数据

XML的操作：

1、Java读取XML数据格式：
代码示例：
一个创建好的XML文件：

<?xml version="1.0" encoding="UTF-8"?><Languages cat="it">    <lan id="1">        <name>Java</name>        <ide>Eclipse</ide>    </lan>    <lan id="2">        <name>Swift</name>        <ide>Xcode</ide>    </lan>    <lan id="3">        <name>C#</name>        <ide>Visual Studio</ide>    </lan></Languages>

用java读取XML中各个标签和子标签及属性的方法：

import java.io.File;import java.io.IOException;import javax.xml.parsers.DocumentBuilder;import javax.xml.parsers.DocumentBuilderFactory;import javax.xml.parsers.ParserConfigurationException;import org.w3c.dom.Document;import org.w3c.dom.Element;import org.w3c.dom.Node;import org.w3c.dom.NodeList;import org.xml.sax.SAXException;public class ReadXML {    public static void main(String[] args) {            try {            //DOM方式解析XML            DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();            DocumentBuilder builder = factory.newDocumentBuilder();            Document document = builder.parse(new File("languages.xml"));            Element root = document.getDocumentElement();            System.out.println("cat=" + root.getAttribute("cat"));            NodeList list = root.getElementsByTagName("lan");            for (int i = 0; i < list.getLength(); i++) {                Element lan = (Element)list.item(i); //Element 继承自Node,由父级到子集需要转换。                System.out.println("--------------");                System.out.println("id = " + lan.getAttribute("id"));                NodeList childs = lan.getChildNodes();                for (int j = 0; j < childs.getLength(); j++) {                    Node node = childs.item(j);//这样的解析方法会把空格和换行也解析出来，创建if语句来解析                    if (node instanceof Element) {                        System.out.println(node.getNodeName() + "=" + node.getTextContent());                    }                }                //这个方法使得代码不专业。                //Element name = (Element) lan.getElementsByTagName("name").item(0);                //System.out.println("name=" + name.getTextContent());            }        } catch (ParserConfigurationException e) {            // TODO Auto-generated catch block            e.printStackTrace();        } catch (SAXException e) {            // TODO Auto-generated catch block            e.printStackTrace();        } catch (IOException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }    }}

2、用Java创建XML数据
代码示例：

import javax.xml.parsers.DocumentBuilder;import javax.xml.parsers.DocumentBuilderFactory;import javax.xml.parsers.ParserConfigurationException;import javax.xml.transform.Transformer;import javax.xml.transform.TransformerConfigurationException;import javax.xml.transform.TransformerException;import javax.xml.transform.TransformerFactory;import javax.xml.transform.dom.DOMSource;import javax.xml.transform.stream.StreamResult;import org.w3c.dom.Document;import org.w3c.dom.Element;public class CreatXML {    public static void main(String[] args) {        try {                   DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();            DocumentBuilder builder = factory.newDocumentBuilder();            Document document = builder.newDocument();            Element root = document.createElement("language");            root.setAttribute("cat", "it");            Element lan1 = document.createElement("lan");            lan1.setAttribute("id", "1");            Element name1 = document.createElement("name");            name1.setTextContent("Java");            Element ide1 = document.createElement("ide");            ide1.setTextContent("Eclipse");            //节点填充            lan1.appendChild(name1);            lan1.appendChild(ide1);            root.appendChild(lan1);            Element lan2 = document.createElement("lan");            lan2.setAttribute("id", "2");            Element name2 = document.createElement("name");            name2.setTextContent("Swift");            Element ide2 = document.createElement("ide");            ide2.setTextContent("XCode");            //节点填充            lan2.appendChild(name2);            lan2.appendChild(ide2);            root.appendChild(lan2);            Element lan3  = document.createElement("lan");            lan3.setAttribute("id", "3");            Element name3 = document.createElement("name");            name3.setTextContent("C#");            Element ide3 = document.createElement("ide");            ide3.setTextContent("Visual Studio");            //节点填充            lan3.appendChild(name3);            lan3.appendChild(ide3);            root.appendChild(lan3);            document.appendChild(root);            //------------            TransformerFactory transformerFactory = TransformerFactory.newInstance();            Transformer transformer = transformerFactory.newTransformer();            StringWriter writer = new StringWriter();            transformer.transform(new DOMSource(document), new StreamResult(writer));            System.out.println(writer.toString());            transformer.transform(new DOMSource(document), new StreamResult("newxml.xml"));        } catch (ParserConfigurationException e) {            // TODO Auto-generated catch block            e.printStackTrace();        } catch (TransformerConfigurationException e) {            // TODO Auto-generated catch block            e.printStackTrace();        } catch (TransformerException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }    }}

3、这种操作方式是一种非常经典的方式：“DOM”。但是这个方式过于繁琐，这里介绍一个方便的操作方式：DOM4J。这个jar和说明文档大家可以下载下来看看，或者留言我邮件给你，这里举了个例子介绍方法：
创建XML：

import org.dom4j.Document;import org.dom4j.DocumentException;import org.dom4j.DocumentHelper;//应用DOM4J操作xml文件，方便快捷public class TestDOM4j {    public static void main(String[] args) {        String xmlString = "<root><people>Alan</people></root>";        try {            Document document = DocumentHelper.parseText(xmlString);            System.out.println(document.asXML());        } catch (DocumentException e) {            e.printStackTrace();        }       }}

不需要应用DocumentBuilderFactory接口和DocumentBuilder类来创建，转化时也不需要用工厂方法TransformerFactory来转化，简便快捷，更多操作方法可以在下载库中的docs文件中查询。