1. Dom概述
Dom方式创建XML,应用了标准xml构造器 javax.xml.parsers.DocumentBuilder 来创建 XML 文档,需要导入以下内容
javax.xml.parsers
javax.xml.transformjavax.xml.parsers.DocumentBuilder
javax.xml.parsers.DocumentBuilderFactory
javax.xml.parsers.ParserConfigurationException;
javax.xml.transform.TransformerFactory
javax.xml.transform.Transformer
javax.xml.transform.dom.DOMSource
javax.xml.transform.stream.StreamResult
javax.xml.transform.OutputKeys;
javax.xml.transform.TransformerFactoryConfigurationError;
javax.xml.transform.TransformerConfigurationException;
javax.xml.transform.TransformerException;
org.w3c.dom
org.w3c.dom.Document;
org.w3c.dom.Element;
org.w3c.dom.Node;
org.w3c.dom.DOMException;
org.w3c.dom.NodeList;
org.xml.sax.SAXException;
sdk源码查看路径(google code)
创建和解析xml的效果图:
2、Dom 创建 XML
Dom,借助 javax.xml.parsers.DocumentBuilder,可以创建 org.w3c.dom.Document 对象。
使用来自 DocumentBuilderFactory 的 DocumentBuilder 对象在 Android 设备上创建与解析 XML 文档。您将使用 XML pull 解析器的扩展来解析 XML 文档。
Code
- /** Dom方式,创建 XML */
- public String domCreateXML() {
- String xmlWriter = null;
- Person []persons = new Person[3]; // 创建节点Person对象
- persons[0] = new Person(1, "sunboy_2050", "http://blog.csdn.net/sunboy_2050");
- persons[1] = new Person(2, "baidu", "http://www.baidu.com");
- persons[2] = new Person(3, "google", "http://www.google.com");
- try {
- DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
- DocumentBuilder builder = factory.newDocumentBuilder();
- Document doc = builder.newDocument();
- Element eleRoot = doc.createElement("root");
- eleRoot.setAttribute("author", "homer");
- eleRoot.setAttribute("date", "2012-04-26");
- doc.appendChild(eleRoot);
- int personsLen = persons.length;
- for(int i=0; i<personsLen; i++) {
- Element elePerson = doc.createElement("person");
- eleRoot.appendChild(elePerson);
- Element eleId = doc.createElement("id");
- Node nodeId = doc.createTextNode(persons[i].getId() + "");
- eleId.appendChild(nodeId);
- elePerson.appendChild(eleId);
- Element eleName = doc.createElement("name");
- Node nodeName = doc.createTextNode(persons[i].getName());
- eleName.appendChild(nodeName);
- elePerson.appendChild(eleName);
- Element eleBlog = doc.createElement("blog");
- Node nodeBlog = doc.createTextNode(persons[i].getBlog());
- eleBlog.appendChild(nodeBlog);
- elePerson.appendChild(eleBlog);
- }
- Properties properties = new Properties();
- properties.setProperty(OutputKeys.INDENT, "yes");
- properties.setProperty(OutputKeys.MEDIA_TYPE, "xml");
- properties.setProperty(OutputKeys.VERSION, "1.0");
- properties.setProperty(OutputKeys.ENCODING, "utf-8");
- properties.setProperty(OutputKeys.METHOD, "xml");
- properties.setProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
- TransformerFactory transformerFactory = TransformerFactory.newInstance();
- Transformer transformer = transformerFactory.newTransformer();
- transformer.setOutputProperties(properties);
- DOMSource domSource = new DOMSource(doc.getDocumentElement());
- OutputStream output = new ByteArrayOutputStream();
- StreamResult result = new StreamResult(output);
- transformer.transform(domSource, result);
- xmlWriter = output.toString();
- } catch (ParserConfigurationException e) { // factory.newDocumentBuilder
- e.printStackTrace();
- } catch (DOMException e) { // doc.createElement
- e.printStackTrace();
- } catch (TransformerFactoryConfigurationError e) { // TransformerFactory.newInstance
- e.printStackTrace();
- } catch (TransformerConfigurationException e) { // transformerFactory.newTransformer
- e.printStackTrace();
- } catch (TransformerException e) { // transformer.transform
- e.printStackTrace();
- } catch (Exception e) {
- e.printStackTrace();
- }
- savedXML(fileName, xmlWriter.toString());
- return xmlWriter.toString();
- }
运行结果:
3、Dom 解析 XML
Dom方式,解析XML是创建XML的逆过程,主要用到了builder.parse(is)进行解析,然后通过Tag、NodeList、Element、childNotes等得到Element和Node属性或值。
Code
- /** Dom方式,解析 XML */
- public String domResolveXML() {
- StringWriter xmlWriter = new StringWriter();
- InputStream is= readXML(fileName);
- try {
- DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
- DocumentBuilder builder = factory.newDocumentBuilder();
- Document doc = builder.parse(is);
- doc.getDocumentElement().normalize();
- NodeList nlRoot = doc.getElementsByTagName("root");
- Element eleRoot = (Element)nlRoot.item(0);
- String attrAuthor = eleRoot.getAttribute("author");
- String attrDate = eleRoot.getAttribute("date");
- xmlWriter.append("root").append("\t\t");
- xmlWriter.append(attrAuthor).append("\t");
- xmlWriter.append(attrDate).append("\n");
- NodeList nlPerson = eleRoot.getElementsByTagName("person");
- int personsLen = nlPerson.getLength();
- Person []persons = new Person[personsLen];
- for(int i=0; i<personsLen; i++) {
- Element elePerson = (Element) nlPerson.item(i); // person节点
- Person person = new Person(); // 创建Person对象
- NodeList nlId = elePerson.getElementsByTagName("id");
- Element eleId = (Element)nlId.item(0);
- String id = eleId.getChildNodes().item(0).getNodeValue();
- person.setId(Integer.parseInt(id));
- NodeList nlName = elePerson.getElementsByTagName("name");
- Element eleName = (Element)nlName.item(0);
- String name = eleName.getChildNodes().item(0).getNodeValue();
- person.setName(name);
- NodeList nlBlog = elePerson.getElementsByTagName("blog");
- Element eleBlog = (Element)nlBlog.item(0);
- String blog = eleBlog.getChildNodes().item(0).getNodeValue();
- person.setBlog(blog);
- xmlWriter.append(person.toString()).append("\n");
- persons[i] = person;
- }
- } catch (ParserConfigurationException e) { // factory.newDocumentBuilder
- e.printStackTrace();
- } catch (SAXException e) { // builder.parse
- e.printStackTrace();
- } catch (IOException e) { // builder.parse
- e.printStackTrace();
- } catch (Exception e) {
- e.printStackTrace();
- }
- return xmlWriter.toString();
- }
运行结果:
4、Person类
Person类,是创建xml的单位实例,基于Java面向对象定义的一个类
- public class Person {
- private int id;
- private String name;
- private String blog;
- public Person() {
- this.id = -1;
- this.name = "";
- this.blog = "";
- }
- public Person(int id, String name, String blog) {
- this.id = id;
- this.name = name;
- this.blog = blog;
- }
- public Person(Person person) {
- this.id = person.id;
- this.name = person.name;
- this.blog = person.blog;
- }
- public Person getPerson(){
- return this;
- }
- public void setId(int id) {
- this.id = id;
- }
- public int getId(){
- return this.id;
- }
- public void setName(String name) {
- this.name = name;
- }
- public String getName() {
- return this.name;
- }
- public void setBlog(String blog) {
- this.blog = blog;
- }
- public String getBlog() {
- return this.blog;
- }
- public String toString() {
- return "Person \nid = " + id + "\nname = " + name + "\nblog = " + blog + "\n";
- }
- }