Android 创建与解析XML（二）—— Dom方式

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.parsers.DocumentBuilder 

javax.xml.parsers.DocumentBuilderFactory 

javax.xml.parsers.ParserConfigurationException;

javax.xml.transform

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";
    }
}

代码下载

参考推荐：

org.w3c.dom

javax.xml.parsers

javax.xml.transform

dom创建xml

java dom创建xml