Android 简易XML解析

Posted 2020-06-29 woider

首先创建在android工程中创建一个Assets文件夹 app/src/main/assets

在这里添加一个名为 data.xml的文件，然后编辑这个文件，加入如下XML格式内容

<?xml version="1.0" encoding="utf-8"?>
<apps>
    <app>
        <id>1</id>
        <name>Google Maps</name>
        <version>1.0</version>
    </app>
    <app>
        <id>2</id>
        <name>Chrome</name>
        <version>2.1</version>
    </app>
    <app>
        <id>3</id>
        <name>Google play</name>
        <version>2.3</version>
    </app>
</apps>

==============获取XML中内容================

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        try {
            //获取XML文件的输入流
            InputStream fis = getResources().getAssets().open("data.xml");
            InputStreamReader isr = new InputStreamReader(fis, "UTF-8");
            StringBuffer stringBuffer = new StringBuffer();
            int mark = -1;
            while ((mark = isr.read()) != -1) {
                stringBuffer.append((char) mark);
            }
            String data = stringBuffer.toString();
            //把整个文件内容以String方式传入
            //parseXMLWithPull(data);
            //parseXMLWithSAX(data);

        } catch (IOException e) {
            e.printStackTrace();
        }

    }

==============Pull解析方式=================

获取解析工具XmlPullParser：
XmlPullParserFactory factory = XmlPullParserFactory.newInstance();
XmlPullParser xmlPullParser = factory.newPullParser();

传入XML字符流：
xmlPullParser.setInput(new StringReader(xmlData));

根据节点特征进行处理：
switch ( xmlPullParser.getEventType() )

    private void parseXMLWithPull(String xmlData) {
        try {
            XmlPullParserFactory factory = XmlPullParserFactory.newInstance();
            XmlPullParser xmlPullParser = factory.newPullParser();
            xmlPullParser.setInput(new StringReader(xmlData));
            int eventType = xmlPullParser.getEventType();
            String id = "";
            String name = "";
            String version = "";
            while (eventType != xmlPullParser.END_DOCUMENT) {
                String nodeName = xmlPullParser.getName();
                switch (eventType) {
                    //开始解析某个节点
                    case XmlPullParser.START_TAG: {
                        if ("id".equals(nodeName)) {
                            id = xmlPullParser.nextText();
                        } else if ("name".equals(nodeName)) {
                            name = xmlPullParser.nextText();
                        } else if ("version".equals(nodeName)) {
                            version = xmlPullParser.nextText();
                        }
                    }
                    break;
                    //完成解析某个节点
                    case XmlPullParser.END_TAG: {
                        if ("app".equals(nodeName)) {
                            Log.d("woider", "id is " + id);
                            Log.d("woider", "name is " + name);
                            Log.d("woider", "version is " + version);
                        }
                    }
                    break;
                }
                eventType = xmlPullParser.next();
            }


        } catch (Exception e) {
            e.printStackTrace();
        }
    }

parseXMLWithPull

 

 ==============SAX解析方式=================

使用SAX解析通常需要创建一个类继承DefaultHandler，并重写父类的五个方法

startDocument()：开始XML解析的时候调用

startElement()：开始解析某个结点的时候调用

characters()：获取节点中内容的时候调用

endElement()：完成解析某个节点的时候调用

endDocument()：完成整个XML解析的时候调用

public class ContentHandler extends DefaultHandler {

    private String nodeName;
    private StringBuilder id;
    private StringBuilder name;
    private StringBuilder version;


    @Override
    public void startDocument() throws SAXException {
        id = new StringBuilder();
        name = new StringBuilder();
        version = new StringBuilder();
    }

    @Override
    public void startElement(String uri, String localName, String qName, Attributes attributes)
            throws SAXException {
        //记住当前结点名
        nodeName = localName;
    }

    @Override
    public void characters(char[] ch, int start, int length) throws SAXException {
        //进行格式规范化
        String str = new String(ch, start, length).trim();
        //根据当前节点名添加内容
        if ("id".equals(nodeName)) {
            id.append(str);
        } else if ("name".equals(nodeName)) {
            name.append(str);
        } else if ("version".equals(nodeName)) {
            version.append(str);
        }
    }

    @Override
    public void endElement(String uri, String localName, String qName) throws SAXException {
        if ("app".equals(localName)) {
            Log.d("woider", "id is " + id);
            Log.d("woider", "name is " + name);
            Log.d("woider", "version is " + version);
            //清空StringBuilder
            id.setLength(0);
            name.setLength(0);
            version.setLength(0);
        }
    }

    @Override
    public void endDocument() throws SAXException {
    }
}

ContentHandler

获取解析工具XMLReader：
SAXParserFactory factory = SAXParserFactory.newInstance();
XMLReader xmlReader = factory.newSAXParser().getXMLReader();

传入规则到解析工具：
ContentHandler handler = new ContentHandler();
xmlReader.setContentHandler(handler);

开始执行解析：
xmlReader.parse(new InputSource(new StringReader(xmlData)));

    private void parseXMLWithSAX(String xmlData) {
        try {
            SAXParserFactory factory = SAXParserFactory.newInstance();
            XMLReader xmlReader = factory.newSAXParser().getXMLReader();
            ContentHandler handler = new ContentHandler();
            //将ContentHandler的实例设置到XMLReader中
            xmlReader.setContentHandler(handler);
            //开始执行解析
            xmlReader.parse(new InputSource(new StringReader(xmlData)));

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

parseXMLWithSAX

 

 　方法二（直接针对InputStream解析）

获取解析工具SAXParser：
SAXParserFactory factory = SAXParserFactory.newInstance();
SAXParser parser = factory.newSAXParser();

获取规则和输入流：
handler = new ParserHandler();
InputStream inputStream = getResources().getAssets().open("data.xml");

同时传入开始解析：
parser.parse(inputStream, handler);

　最后打印 LogCat 中的日志，data.xml的解析就完成了

除了 Pull 解析和 SAX 解析之外，还有一种 DOM 解析也非常重要。

另外还有一些XML解析工具，比如 JDOM 和 DOM4J，它们简化了解析的步骤，提高了解析的效率。