Java与XML原来可以这么简单--基于XMLPull的解析器

XmlPull和Sax类似，是基于流（stream）操作文件，然后根据节点事件回调开发者编写的处理程序。因为是基于流的处理，因此Xmlpull和Sax都比较节约内存资源，不会象Dom那样要把所有节点以对橡树的形式展现在内存中。

但Xmlpull比Sax更简明，而且不需要扫描完整个流。现在XmlPull是一开源项目，并成为了Google android类库的一部分，想了解更多请查看http://www.xmlpull.org。XmlPull的jar以及源文件见附件。

 

XmlPull使用起来很简单，下面献上一自己写的实例，xml数据由google weather api提供：http://easymorse.googlecode.com/svn/tags/android.xmlpull.google.weather-1.0/assets/weather.xml

 

public class xmlPuller {

	public static void main(String[] args) {
		XmlPullParser xpp = null;
		String url = "http://easymorse.googlecode.com/svn/tags/android.xmlpull.google.weather-1.0/assets/weather.xml";
		String filename = "weather.xml";
		FileInputStream fis = null;
		InputStream is = null;
		try {
			if(getRemoteFile(url,filename)){
				fis = new FileInputStream(new File("weather.xml"));
				is = new BufferedInputStream(fis); 
				XmlPullParserFactory factory = XmlPullParserFactory.newInstance();
				factory.setNamespaceAware(true);
				xpp = factory.newPullParser();
				xpp.setInput(is,"utf-8");
				int type = xpp.getEventType();
				StringBuilder sb = new StringBuilder();
				while(type!=XmlPullParser.END_DOCUMENT){
					switch(type){
					case XmlPullParser.START_DOCUMENT:
						sb.append("Start document");
						break;
					case XmlPullParser.START_TAG:
						sb.append("Start tag:" + xpp.getName() + "\n");
						for(int i=0;i<xpp.getAttributeCount();i++){
							sb.append("\t Attr:" + xpp.getAttributeName(i) + "--");
							sb.append("Value:" + xpp.getAttributeValue(i));
						}
						break;
					case XmlPullParser.END_TAG:
						sb.append("End tag:" + xpp.getName());
						break;
					case XmlPullParser.TEXT:
						if(xpp.getText().endsWith("")){
							sb.append("\t Start text: null");
						} else {
							sb.append("\t Start text:" + xpp.getText());
						}
						break;
					default:break;
					}
					System.out.println(sb.toString());
					sb.delete(0, sb.length());
					xpp.next();
					type = xpp.getEventType();
				}
				
				System.out.println("End document");
			}
		}catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}catch (XmlPullParserException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} finally {
				try {
					if(is!=null){
					is.close();
					}
					if(fis!=null){
						fis.close();
					}
				} catch (IOException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}	
		}		
	}

   

 

 运行时经常会遇到以下的异常：

 

caused by: org.xmlpull.v1.XmlPullParserException: resource not found: /META-INF/services/org.xmlpull.v1.XmlPullParserFactory make sure that parser implementing XmlPull API is available; nested exception is:
org.xmlpull.v1.XmlPullParserException: resource not found: /META-INF/services/org.xmlpull.v1.XmlPullParserFactory make sure that parser implementing XmlPull API is available
	at org.xmlpull.v1.XmlPullParserFactory.newInstance(XmlPullParserFactory.java:278)
	at org.xmlpull.v1.XmlPullParserFactory.newInstance(XmlPullParserFactory.java:259)
	at xmlPuller.main(xmlPuller.java:28)

  

XmlPullParserException:resource not found！

没有找到这样的资源：META-INF/services/org.xmlpull.v1.XmlPullParserFactory

so，我们就为它添加这样的资源：

 

       将http://kxml.sourceforge.net/下载的kxml2.jar加到你的项目中即可。

     kxml2.jar就包含了META-INF/services/org.xmlpull.v1.XmlPullParserFactory文件，它的内容其实就是一句话：

      org.kxml2.io.KXmlParser,org.kxml2.io.KXmlSerializer

 

     

评论

2 楼 a86261566 2015-08-21  

多谢   简单易懂

1 楼 wangshiming 2011-09-16  

兄台，你的getRemoteFile(url,filename)方法是执行什么功能啊，是不是忘记贴出来了