Android学习笔记之XML解析（SAX）

SAX是一种占用内存少且解析速度快的解析器，它采用的是事件启动，它不需要解析完整个文档，而是按照内容顺序 看文档某个部分是否符合xml语法，如果符合就触发相应的事件，所谓的事件就是些回调方法（callback）,这些方法 定义在ContentHandler中，下面是其主要方法：

startDocument:当遇到文档的时候就触发这个事件 调用这个方法 可以在其中做些预处理工作

startElement: (String namespaceURI,String localName,String qName,Attributes atts)当遇开始标签的时候就会触发这个方法。

endElement（String uri,String localName,String name）：当遇到结束标签时触发这个事件，调用此法可以做些善后工作。

charachers(char [] ch,int start,int length):当遇到xml内容时触发这个方法，用new String(ch,start,length)可以接受内容。

MyContentHandler.java

package mars.xml;

import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;

public class MyContentHandler extends DefaultHandler {
	String hisname, address, money, sex, status;
	String tagName;

	public void startDocument() throws SAXException {
		System.out.println("````````begin````````");
	}

	public void endDocument() throws SAXException {
		System.out.println("````````end````````");
	}

	public void startElement(String namespaceURI, String localName,
			String qName, Attributes attr) throws SAXException {
		tagName = localName;
		if (localName.equals("worker")) {
			//获取标签的全部属性
			for (int i = 0; i < attr.getLength(); i++) {
				System.out.println(attr.getLocalName(i) + "=" + attr.getValue(i));
			}
		}
	}

	public void endElement(String namespaceURI, String localName, String qName)
			throws SAXException {
		//在workr标签解析完之后，会打印出所有得到的数据
		tagName = "";
		if (localName.equals("worker")) {
			this.printout();
		}
	}
	public void characters(char[] ch, int start, int length)
			throws SAXException {
		if (tagName.equals("name"))
			hisname = new String(ch, start, length);
		else if (tagName.equals("sex"))
			sex = new String(ch, start, length);
		else if (tagName.equals("status"))
			status = new String(ch, start, length);
		else if (tagName.equals("address"))
			address = new String(ch, start, length);
		else if (tagName.equals("money"))
			money = new String(ch, start, length);
	}

	private void printout() {
		System.out.print("name: ");
		System.out.println(hisname);
		System.out.print("sex: ");
		System.out.println(sex);
		System.out.print("status: ");
		System.out.println(status);
		System.out.print("address: ");
		System.out.println(address);
		System.out.print("money: ");
		System.out.println(money);
		System.out.println();
	}

}

XMLActitity.java

package mars.xml;

import java.io.StringReader;

import javax.xml.parsers.SAXParserFactory;

import mars.utils.HttpDownloader;

import org.xml.sax.InputSource;
import org.xml.sax.XMLReader;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class XMLActitity extends Activity {
    /** Called when the activity is first created. */
	private Button parseButton ;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        parseButton = (Button)findViewById(R.id.parseButton);
        parseButton.setOnClickListener(new ParseButtonListener());
    }
    
    class ParseButtonListener implements OnClickListener{

		public void onClick(View v) {
			HttpDownloader hd = new HttpDownloader();
			String resultStr = hd.download("http://192.168.1.107:8081/voa1500/test.xml");
			System.out.println(resultStr);
			try{
				//创建一个SAXParserFactory
				SAXParserFactory factory = SAXParserFactory.newInstance();
				XMLReader reader = factory.newSAXParser().getXMLReader();
				//为XMLReader设置内容处理器
				reader.setContentHandler(new MyContentHandler());
				//开始解析文件
				reader.parse(new InputSource(new StringReader(resultStr)));
			}
			catch(Exception e){
				e.printStackTrace();
			}
		}
    	
    }
}