JAVA解析XML的四种方法--SAX

优点：不用事先调入整个文档，占用资源少；SAX解析器代码比DOM解析器代码小，适于Applet，下载。

缺点：不是持久的；事件过后，若没保存数据，那么数据就丢了；无状态性；从事件中只能得到文本，但不知该文本属于哪个元素；使用场合：Applet;只需XML文档的少量内容，很少回头访问；机器内存少。

import java.io.IOException;
import java.util.logging.Handler;

import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;

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

public class SAX {
	
	
	public static void main(String[] args) {
		SAXParserFactory factory = SAXParserFactory.newInstance();
		try {
			SAXParser parser =  factory.newSAXParser();
			//SAXParserHandler handler = new SAXParserHandler();
			parser.parse("books.xml", new SAXParserHandler());
			
			
		} catch (ParserConfigurationException e) {
			e.printStackTrace();
		} catch (SAXException e) {
			e.printStackTrace();
		}catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
	}

}

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

public class SAXParserHandler extends DefaultHandler {
	
	/**
	 * <>---------</>之间
	 */
	@Override
	public void characters(char[] ch, int start, int length) throws SAXException {
		super.characters(ch, start, length);
		String value = new String(ch, start, length);
			System.out.print(value.trim());
	}
	
	@Override
	public void startDocument() throws SAXException {
		super.startDocument();
		System.err.println("----开始解析----\n");
	}

	@Override
	public void endDocument() throws SAXException {
		super.endDocument();
		System.out.println("\n----结束解析----");
	}

	/**
	 *endElement获得</>之前内容 
	 */
	@Override
	public void endElement(String uri, String localName, String qName) throws SAXException {
		super.endElement(uri, localName, qName);
		if(qName!="book" && qName!="bookstore")
			System.out.println("-------" + qName);
		
	}

	

	/**
	 * startElement获得标签<>内属性
	 */
	@Override
	public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
		super.startElement(uri, localName, qName, attributes);
		if(attributes.getLength() != 0) {
			System.out.print(qName + "的属性:----");
			for(int i=0; i<attributes.getLength(); i++) {
			    System.out.print(attributes.getQName(i) + " = " + attributes.getValue(i));
			    System.out.println("\n");
				}
		    }
}

}