Android：如何解析这种XML

Question

I have an XML document, and I need to parse in order to extract, for each item, the value of:

<title>
<description>
<articleDate>
<story>
<author>
<photo>
<caption>

I am trying with DOM, but I am a lost because each node

<item>

of the root

<channel> 

has 3 children:

<article>
<media> 
<link>

Answer 1

Maybe this can help: http://www.mkyong.com/java/how-to-modify-xml-file-in-java-dom-parser/

How to append tags in XML in Android?

other example:

final String xmlFile = "YourFile.xml";
    ArrayList<String> userData = new ArrayList<String>();
    FileInputStream fis;
    InputStreamReader isr;
    String data = null;
    try {
        fis = c.openFileInput(xmlFile);
        isr = new InputStreamReader(fis);
        char[] inputBuffer = new char[fis.available()];
        isr.read(inputBuffer);
        data = new String(inputBuffer);
        isr.close();
        fis.close();
    } catch (FileNotFoundException e3) {
        // TODO Auto-generated catch block
        e3.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    XmlPullParserFactory factory = null;
    try {
        factory = XmlPullParserFactory.newInstance();
    } catch (XmlPullParserException e2) {
        // TODO Auto-generated catch block
        e2.printStackTrace();
    }
    factory.setNamespaceAware(true);
    XmlPullParser xpp = null;
    try {
        xpp = factory.newPullParser();
    } catch (XmlPullParserException e2) {
        // TODO Auto-generated catch block
        e2.printStackTrace();
    }
    try {
        xpp.setInput(new StringReader(data));
    } catch (XmlPullParserException e1) {
        // TODO Auto-generated catch block
        e1.printStackTrace();
    }
    int eventType = 0;
    try {
        eventType = xpp.getEventType();
    } catch (XmlPullParserException e1) {
        // TODO Auto-generated catch block
        e1.printStackTrace();
    }
    while (eventType != XmlPullParser.END_DOCUMENT) {
        if (eventType == XmlPullParser.START_DOCUMENT) {
            System.out.println("Start document");
        } else if (eventType == XmlPullParser.START_TAG) {
            System.out.println("Start tag " + xpp.getName());

        } else if (eventType == XmlPullParser.END_TAG) {
            System.out.println("End tag " + xpp.getName());
        } else if (eventType == XmlPullParser.TEXT) {
            userData.add(xpp.getText());
            System.out.println(xpp.getText());
        }
        try {
            eventType = xpp.next();
        } catch (XmlPullParserException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

}   

Answer 2

item是您的根。您必须使用sax解析器来粗化这个xml。 请看这里

Answer 3

I've had a lot of success using SAX, it's fast and simple. I got the idea for this simple and 'recursive' method show below from some websites that demonstrated a template based parser generator. I simply do it by hand, but extend from the 'DefaultHandler' class.

The real trick here, is that each object type gets it's own 'DefaultHandler' extension that knows how to parse THAT type and that type alone. This makes refactoring and reusing your parsers your XML and parsers possible. Then, whenever you see the start of a new child 'element' of some type, you create an empty child container and it's extension of 'DefaultHandler'. Set the current handler to the one for that type and let it recursively chomp away.

There are improvements I could make with this too, like pushing the some of the common methods up to my own base class that extends 'DefaultHandler'. I also created the 'IXMLSerializer' interface, so that I could quickly write these out. There may be a better way for that too.

Taking the sting out of SAX

Based on this, I came up with a strategy to start by creating objects for each of the element types...

public class CollectionType implements IXMLSerializer{

public static final String  TYPE_TAG = "Collection";

protected IdentityType identity;
protected List<PropertyType> property;
protected List<ItemReferenceType> itemReference;
protected List<SporeType> spore;
protected List<RegionType> region;
protected List<BackpackItemType> backpackItem;


/**
 * Gets the value of the identity property.
 * 
 * @return
 *     possible object is
 *     {@link IdentityType }
 *     
 */
public IdentityType getIdentity() {
    return identity;
}

/**
 * Sets the value of the identity property.
 * 
 * @param value
 *     allowed object is
 *     {@link IdentityType }
 *     
 */
public void setIdentity(IdentityType value) {
    this.identity = value;
}


/**
 * Gets the value of the property property.
 * 
 * <p>
 * This accessor method returns a reference to the live list,
 * not a snapshot. Therefore any modification you make to the
 * returned list will be present inside the JAXB object.
 * This is why there is not a <CODE>set</CODE> method for the property property.
 * 
 * <p>
 * For example, to add a new item, do as follows:
 * <pre>
 *    getProperty().add(newItem);
 * </pre>
 * 
 * 
 * <p>
 * Objects of the following type(s) are allowed in the list
 * {@link PropertyType }
 * 
 * 
 */
public List<PropertyType> getProperty() {
    if (property == null) {
        property = new ArrayList<PropertyType>();
    }
    return this.property;
}

/**
 * Gets the value of the itemReference property.
 * 
 * <p>
 * This accessor method returns a reference to the live list,
 * not a snapshot. Therefore any modification you make to the
 * returned list will be present inside the JAXB object.
 * This is why there is not a <CODE>set</CODE> method for the itemReference property.
 * 
 * <p>
 * For example, to add a new item, do as follows:
 * <pre>
 *    getItemReference().add(newItem);
 * </pre>
 * 
 * 
 * <p>
 * Objects of the following type(s) are allowed in the list
 * {@link ItemReferenceType }
 * 
 * 
 */
public List<ItemReferenceType> getItemReference() {
    if (itemReference == null) {
        itemReference = new ArrayList<ItemReferenceType>();
    }
    return this.itemReference;
}

/**
 * Gets the value of the spore property.
 * 
 * <p>
 * This accessor method returns a reference to the live list,
 * not a snapshot. Therefore any modification you make to the
 * returned list will be present inside the JAXB object.
 * This is why there is not a <CODE>set</CODE> method for the spore property.
 * 
 * <p>
 * For example, to add a new item, do as follows:
 * <pre>
 *    getSpore().add(newItem);
 * </pre>
 * 
 * 
 * <p>
 * Objects of the following type(s) are allowed in the list
 * {@link SporeType }
 * 
 * 
 */
public List<SporeType> getSpore() {
    if (spore == null) {
        spore = new ArrayList<SporeType>();
    }
    return this.spore;
}

/**
 * Gets the value of the region property.
 * 
 * <p>
 * This accessor method returns a reference to the live list,
 * not a snapshot. Therefore any modification you make to the
 * returned list will be present inside the JAXB object.
 * This is why there is not a <CODE>set</CODE> method for the region property.
 * 
 * <p>
 * For example, to add a new item, do as follows:
 * <pre>
 *    getRegion().add(newItem);
 * </pre>
 * 
 * 
 * <p>
 * Objects of the following type(s) are allowed in the list
 * {@link RegionType }
 * 
 * 
 */
public List<RegionType> getRegion() {
    if (region == null) {
        region = new ArrayList<RegionType>();
    }
    return this.region;
}

/**
 * Gets the value of the backpackItem property.
 * 
 * <p>
 * This accessor method returns a reference to the live list,
 * not a snapshot. Therefore any modification you make to the
 * returned list will be present inside the JAXB object.
 * This is why there is not a <CODE>set</CODE> method for the backpackItem property.
 * 
 * <p>
 * For example, to add a new item, do as follows:
 * <pre>
 *    getBackpackItem().add(newItem);
 * </pre>
 * 
 * 
 * <p>
 * Objects of the following type(s) are allowed in the list
 * {@link BackpackItemType }
 * 
 * 
 */
public List<BackpackItemType> getBackpackItem() {
    if (backpackItem == null) {
        backpackItem = new ArrayList<BackpackItemType>();
    }
    return this.backpackItem;
}

@Override
public void serializeType(XmlSerializer serializer, String namespace)
        throws IllegalArgumentException, IllegalStateException, IOException {

    serializer.startTag(namespace, TYPE_TAG);
    getIdentity().serializeType(serializer, namespace);

    Iterator<PropertyType> pItor = getProperty().iterator();
    while (pItor.hasNext()){
        pItor.next().serializeType(serializer, namespace);
    }

    Iterator<ItemReferenceType> iItor = getItemReference().iterator();
    while (iItor.hasNext()){
        iItor.next().serializeType(serializer, namespace);
    }

    Iterator<SporeType> sItor = getSpore().iterator();
    while (sItor.hasNext()){
        sItor.next().serializeType(serializer, namespace);
    }

    Iterator<RegionType> rItor = getRegion().iterator();
    while (rItor.hasNext()){
        rItor.next().serializeType(serializer, namespace);
    }

    Iterator<BackpackItemType> bItor = getBackpackItem().iterator();
    while (bItor.hasNext()){
        bItor.next().serializeType(serializer, namespace);
    }

    serializer.endTag(namespace, TYPE_TAG);
}

}

Then, I create a top level document handler....

public class DocumentHandler extends DefaultHandler {
public static final String      TAG = DocumentHandler.class.getSimpleName();
private static final boolean    mDebugLogging = true;

SAXParserFactory        mSaxParserFactory;
SAXParser               mSaxParser;
XMLReader               mXmlReader;
Stack<String>           mElementStack = new Stack<String>();

private CollectionType  mCollection = null;
private RequestType     mRequest = null;
private ResponseType    mResponse = null;




public DocumentHandler() throws SAXException, ParserConfigurationException{
    mSaxParserFactory = SAXParserFactory.newInstance();
    mSaxParserFactory.setNamespaceAware(true);      //  Must be set true, otherwise no attributes!
    //m_saxParserFactory.setFeature("http://xml.org/sax/features/namespaces", true);
    //m_saxParserFactory.setFeature("http://xml.org/sax/features/namespace-prefixes", true);
    mSaxParser = mSaxParserFactory.newSAXParser();

    if (mDebugLogging) {
        Log.d(TAG, "SAX parser namespace aware? " + mSaxParser.isNamespaceAware());
        Log.d(TAG, "SAX parser is validating? " + mSaxParser.isValidating());
    }
    mXmlReader = mSaxParser.getXMLReader();
}

@Override
public void endDocument() throws SAXException {
    if (mDebugLogging) {
        Log.d(TAG, "Beginning Document Parse");
    }
    super.endDocument();
}




@Override
public void startDocument() throws SAXException {
    if (mDebugLogging) {
        Log.d(TAG, "Ending Document Parse");
    }
    super.startDocument();
}


@Override
public void startElement(java.lang.String uri, java.lang.String localName, java.lang.String qName, Attributes attributes) throws SAXException {
    if (qName.equals("Collection")) {
        mCollection = new CollectionType();
        final DefaultHandler handler = new CollectionHandler(mElementStack, mCollection, attributes, mXmlReader, this);
        mElementStack.push ("ServerResponse");
        mXmlReader.setContentHandler (handler);
    }
    else if (qName.equals("Request")){
        mRequest = new RequestType();
        final DefaultHandler handler = new RequestHandler(mElementStack, mRequest, attributes, mXmlReader, this);
        mElementStack.push("Request");
        mXmlReader.setContentHandler(handler);
    }
    else if (qName.equals("Response")){
        mResponse = new ResponseType();
        final DefaultHandler handler = new ResponseHandler(mElementStack, mResponse, attributes, mXmlReader, this);
        mElementStack.push("Response");
        mXmlReader.setContentHandler(handler);
    }
}


@Override
public void endElement(java.lang.String uri, java.lang.String localName, java.lang.String qName) throws SAXException {}


public void parse(InputSource is) throws SAXException, IOException {
    mXmlReader.setContentHandler(this);
    mXmlReader.parse(is);
}


public RequestType parseRequest(InputStream inStream) throws SAXException, IOException {
    final InputSource inSource = new InputSource(inStream);
    parse(inSource);
    return mRequest;
}

public CollectionType parseCollection(InputStream inStream) throws SAXException, IOException {
    final InputSource inSource = new InputSource(inStream);
    parse(inSource);
    return mCollection;
}

public ResponseType parseResponse(InputStream inStream) throws SAXException, IOException {
    final InputSource inSource = new InputSource(inStream);
    parse(inSource);
    return mResponse;
}

}

Then I extend 'DefaultHandler' for each of the types like this:

public class CollectionHandler extends DefaultHandler { private final CharArrayWriter m_textBuffer = new CharArrayWriter (); private final Stack m_elementStack; private final DefaultHandler m_parent; private final XMLReader m_parser;

private final CollectionType            m_collection;

public CollectionHandler(Stack<String> path, CollectionType collection, Attributes attributes, XMLReader parser, DefaultHandler parent) throws SAXException{
    m_elementStack = path;
    m_collection = collection;
    m_parser = parser;
    m_parent = parent;
    start(attributes);
}

private void start(Attributes attributes){}


@Override
public void startElement(java.lang.String uri, java.lang.String localName, java.lang.String qName, Attributes attributes) throws SAXException {
    m_textBuffer.reset();

    if (qName.equals("Identity")){
        final IdentityType identity = new IdentityType();
        m_collection.setIdentity(identity);
        final DefaultHandler handler = new IdentityHandler(m_elementStack, identity, attributes, m_parser, this);
        m_elementStack.push("Identity");
        m_parser.setContentHandler(handler);
    }

    if (qName.equals("BackpackItem")){
        final BackpackItemType backpackItem = new BackpackItemType();
        m_collection.getBackpackItem().add(backpackItem);
        final DefaultHandler handler = new BackpackItemHandler(m_elementStack, backpackItem, attributes, m_parser, this);
        m_elementStack.push("BackpackItem");
        m_parser.setContentHandler(handler);
    }

    else if (qName.equals("ItemReference")){
        final ItemReferenceType itemReference = new ItemReferenceType();
        m_collection.getItemReference().add(itemReference);
        final DefaultHandler handler = new ItemReferenceHandler(m_elementStack, itemReference, attributes, m_parser, this);
        m_elementStack.push("ItemReference");
        m_parser.setContentHandler(handler);
    }

    else if (qName.equals("Property")){
        final PropertyType property = new PropertyType();
        m_collection.getProperty().add(property);
        final DefaultHandler handler = new PropertyHandler(m_elementStack, property, attributes, m_parser, this);
        m_elementStack.push("Property");
        m_parser.setContentHandler(handler);
    }

    else if (qName.equals("Region")){
        final RegionType toInsert = new RegionType();
        m_collection.getRegion().add(toInsert);
        final DefaultHandler handler = new RegionHandler(m_elementStack, toInsert, attributes, m_parser, this);
        m_elementStack.push("Region");
        m_parser.setContentHandler(handler);
    }

    else if (qName.equals("Spore")){
        final SporeType toInsert = new SporeType();
        m_collection.getSpore().add(toInsert);
        final DefaultHandler handler = new SporeHandler(m_elementStack, toInsert, attributes, m_parser, this);
        m_elementStack.push ("Spore");
        m_parser.setContentHandler (handler);
    }
}


@Override
public void endElement(java.lang.String uri, java.lang.String localName, java.lang.String qName) throws SAXException {
    if (qName.equals("Collection")){
        m_elementStack.pop();
        m_parser.setContentHandler(m_parent);
    }
}

}