Android Xml文件操作

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Android 文件操作
Android SQLite应用
Android Xml文件操作
Android SharedPreferences应用
Android Json应用

1. Xml文件写操作

数据类

public class People {	
    public int id;
    public String name;
    public String addr;
    public int age;
}

XmlSerializer写操作，以startDocument开始，endDocument结束。attribute()保存属性,text()保存文本。

private void writeXml(OutputStream output, List<People> peopleList) throws IOException {
    XmlSerializer xmlSerializer = Xml.newSerializer();

    xmlSerializer.setOutput(output, CHARSET);
    xmlSerializer.startDocument(CHARSET, true);

    xmlSerializer.startTag(null, TAG_ROOT);

    for (People people : peopleList) {
        xmlSerializer.startTag(null, TAG_PEOPLE);
        xmlSerializer.attribute(null, TAG_ID, Integer.toString(people.id));

        writeTextTag(xmlSerializer, TAG_NAME, people.name);
        writeTextTag(xmlSerializer, TAG_ADDR, people.addr);
        writeTextTag(xmlSerializer, TAG_AGE, Integer.toString(people.age));

        xmlSerializer.endTag(null, TAG_PEOPLE);
    }

    xmlSerializer.endTag(null, TAG_ROOT);
    xmlSerializer.endDocument();
}

private void writeTextTag(XmlSerializer xmlSerializer, String tag, String text)
        throws IOException {
    xmlSerializer.startTag(null, tag);
    xmlSerializer.text(text);
    xmlSerializer.endTag(null, tag);
}

people.xml文件

<?xml version='1.0' encoding='utf-8' standalone='yes' ?>
<peoples>
	<people id="1">
		<name>Mike</name>
		<addr>ShangHai</addr>
		<age>20</age>
	</people>
	<people id="2">
		<name>Tom</name>
		<addr>BeiJing</addr>
		<age>23</age>
	</people>
	<people id="3">
		<name>Lily</name>
		<addr>ShenZhen</addr>
		<age>21</age>
	</people>
	<people id="4">
		<name>Jack</name>
		<addr>GuangZhou</addr>
		<age>22</age>
	</people>
</peoples>

2. Xml文件读操作

(1) DOM方式，一次读入全部文档，优点是比较直观

private List<People> readXmlByDom(InputStream input) throws Exception {
    List<People> peopleList = new ArrayList<>();

    DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
    DocumentBuilder builder = factory.newDocumentBuilder();
    Document document = builder.parse(input);
    Element root = document.getDocumentElement();

    NodeList nodeList = root.getElementsByTagName(TAG_PEOPLE);

    for (int index = 0; index < nodeList.getLength(); index++) {
        Element peopleElement = (Element) nodeList.item(index);
        String id = peopleElement.getAttribute(TAG_ID);

        People people = new People();
        people.id = Integer.parseInt(id);

        people.name = readText(peopleElement, TAG_NAME);
        people.addr = readText(peopleElement, TAG_ADDR);
        people.age = Integer.parseInt(readText(peopleElement, TAG_AGE));

        peopleList.add(people);
    }
    return peopleList;
}

private String readText(Element parent, String tag) {
    return parent.getElementsByTagName(tag).item(0).getTextContent();
}

(2) SAX方式，逐行读入，需要指定Handler

private List<People> readXmlBySax(InputStream input) throws Exception {
    SAXParserFactory factory = SAXParserFactory.newInstance();
    PeopleHandler handler = new PeopleHandler();

    SAXParser parser = factory.newSAXParser();
    XMLReader xmlReader = parser.getXMLReader();
    xmlReader.setContentHandler(handler);

    xmlReader.parse(new InputSource(input));

    return handler.getPeopleList();
}

private static class PeopleHandler extends DefaultHandler {
    private List<People> peopleList = new ArrayList<>();
    private People people;
    private String text;

    @Override
    public void startElement(String uri, String localName, String qName,
                             Attributes attributes) throws SAXException {
        if (TAG_PEOPLE.equals(localName)) {
            people = new People();
            people.id = Integer.parseInt(attributes.getValue(TAG_ID));
        }
    }

    @Override
    public void endElement(String uri, String localName, String qName) throws SAXException {
        if (TAG_PEOPLE.equals(localName)) {
            peopleList.add(people);
        } else if (TAG_NAME.equals(localName)) {
            people.name = text;
        } else if (TAG_ADDR.equals(localName)) {
            people.addr = text;
        } else if (TAG_AGE.equals(localName)) {
            people.age = Integer.parseInt(text);
        }
    }

    @Override
    public void characters(char[] ch, int start, int length) throws SAXException {
        super.characters(ch, start, length);

        text = new String(ch, start, length);
    }

    public List<People> getPeopleList() {
        return peopleList;
    }
}

(3) PULL方式，与SAX方法一样
private List readXmlByPull(InputStream input) throws Exception {
List peopleList = new ArrayList<>();

    XmlPullParserFactory factory = XmlPullParserFactory.newInstance();
    XmlPullParser parser = factory.newPullParser();
    parser.setInput(new InputStreamReader(input));

    int eventType = parser.getEventType();
    People people = null;
    String text = null;

    while (eventType != XmlPullParser.END_DOCUMENT) {
        if (eventType == XmlPullParser.START_TAG) {
            if (TAG_PEOPLE.equals(parser.getName())) {
                people = new People();
                people.id = Integer.parseInt(parser.getAttributeValue(null, TAG_ID));
            }
        } else if (eventType == XmlPullParser.END_TAG) {
            if (TAG_PEOPLE.equals(parser.getName())) {
                peopleList.add(people);
            } else if (TAG_NAME.equals(parser.getName())) {
                people.name = text;
            } else if (TAG_ADDR.equals(parser.getName())) {
                people.addr = text;
            } else if (TAG_AGE.equals(parser.getName())) {
                people.age = Integer.parseInt(text);
            }
        } else if (eventType == XmlPullParser.TEXT) {
            text = parser.getText();
        }
        eventType = parser.next();
    }
    return peopleList;
}