使用 XmlPull 解析 XML 的簡單例子

XmlPull和Sax類似，是基于流（stream）操作文件，然后根據節點事件回調開發者編寫的處理程序。因為是基于流的處理，因此Xmlpull和 Sax都比較節約內存資源，不會象Dom那樣要把所有節點以對橡樹的形式展現在內存中。 但Xmlpull比Sax更簡明，而且不需要掃描完整個流。
而 MXP1是實現XmlPull的一個java類庫

import java.io.FileReader;
import java.io.IOException;
import java.io.StringReader;

import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;
import org.xmlpull.v1.XmlPullParserFactory;
/**

An example of an application that uses XMLPULL V1 API.
*
@author <a href="http://www.extreme.indiana.edu/~aslom/">Aleksander Slominski</a>
*/
public class MyXmlPullApp
{
public final static String SAMPLE_XML =

 "<?xml version=\"1.0\"?>\n"+
 "\n"+
 "<poem xmlns=\"http://www.megginson.com/ns/exp/poetry\">\n"+
 "<title>Roses are Red</title>\n"+
 "<l>Roses are red,</l>\n"+
 "<l>Violets are blue;</l>\n"+
 "<l>Sugar is sweet,</l>\n"+
 "<l>And I love you.</l>\n"+
 "</poem>";


public static void main (String args[])

 throws XmlPullParserException, IOException

{

 XmlPullParserFactory factory = XmlPullParserFactory.newInstance();
 factory.setNamespaceAware(true);
 XmlPullParser xpp = factory.newPullParser();
 System.out.println("parser implementation class is "+xpp.getClass());

 MyXmlPullApp app = new MyXmlPullApp();

 if(args.length == 0) {
     System.out.println("Parsing simple sample XML");//:\n"+ SAMPLE_XML);
     xpp.setInput( new StringReader( SAMPLE_XML ) );
     app.processDocument(xpp);
 } else {
     for (int i = 0; i < args.length; i++) {
         System.out.println("Parsing file: "+args[i]);
         xpp.setInput ( new FileReader ( args [i] ) );
         app.processDocument(xpp);
     }
 }

}



public void processDocument(XmlPullParser xpp)
    throws XmlPullParserException, IOException
{
    int eventType = xpp.getEventType();
    do {
        if(eventType == xpp.START_DOCUMENT) {
            System.out.println("Start document");
        } else if(eventType == xpp.END_DOCUMENT) {
            System.out.println("End document");
        } else if(eventType == xpp.START_TAG) {
            processStartElement(xpp);
        } else if(eventType == xpp.END_TAG) {
            processEndElement(xpp);
        } else if(eventType == xpp.TEXT) {
            processText(xpp);
        }
        eventType = xpp.next();
    } while (eventType != xpp.END_DOCUMENT);
}


public void processStartElement (XmlPullParser xpp)
{
    String name = xpp.getName();
    String uri = xpp.getNamespace();
    if ("".equals (uri)) {
        System.out.println("Start element: " + name);
    } else {
        System.out.println("Start element: {" + uri + "}" + name);
    }
}


public void processEndElement (XmlPullParser xpp)
{
    String name = xpp.getName();
    String uri = xpp.getNamespace();
    if ("".equals (uri))
        System.out.println("End element: " + name);
    else
        System.out.println("End element:   {" + uri + "}" + name);
}

int holderForStartAndLength[] = new int[2];

public void processText (XmlPullParser xpp) throws XmlPullParserException
{
    char ch[] = xpp.getTextCharacters(holderForStartAndLength);
    int start = holderForStartAndLength[0];
    int length = holderForStartAndLength[1];
    System.out.print("Characters:    \"");
    for (int i = start; i < start + length; i++) {
        switch (ch[i]) {
            case '\\':
                System.out.print("\\\\");
                break;
            case '"':
                System.out.print("\\\"");
                break;
            case '\n':
                System.out.print("\\n");
                break;
            case '\r':
                System.out.print("\\r");
                break;
            case '\t':
                System.out.print("\\t");
                break;
            default:
                System.out.print(ch[i]);
                break;
        }
    }
    System.out.print("\"\n");
}

}</pre>