使用jaxp对比xml进行SAX解析

package cn.itcast.sax;

import java.io.IOException;

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

import org.xml.sax.Attributes;
import org.xml.sax.ContentHandler;
import org.xml.sax.Locator;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.DefaultHandler;

public class Demo1 {

    /**
     *sax方式解析book1.xml文件
     * @throws SAXException
     * @throws ParserConfigurationException
     * @throws IOException
     */
    public static void main(String[] args) throws ParserConfigurationException, SAXException, IOException {

        //1.创建工厂
        SAXParserFactory factory = SAXParserFactory.newInstance();

        //2.用工厂创建解析器
        SAXParser sp = factory.newSAXParser();

        //3.利用解析器得到reader
        XMLReader reader = sp.getXMLReader();

        //4、在解析xml文档之前，设置好事件处理器
        reader.setContentHandler(new MyContentHandler2());

        //4.利用reader读取 xml文档
        reader.parse("src/book1.xml");
    }
}
//用于获取第一个售价节点的值：<售价>109</售价>
class MyContentHandler2 extends DefaultHandler{

    private boolean isOk = false;
    private int index = 1;
    @Override
    public void characters(char[] ch, int start, int length)
            throws SAXException {
        if(isOk==true && index==1){
            System.out.println(new String(ch,start,length));
        }
    }

    @Override
    public void startElement(String uri, String localName, String name,
            Attributes attributes) throws SAXException {
        if(name.equals("售价")){
            isOk = true;
        }
    }

    @Override
    public void endElement(String uri, String localName, String name)
            throws SAXException {
        if(name.equals("售价")){
            isOk = false;
            index++;
        }
    }

}

//得到xml文档内容的事件处理器
class MyContentHandler implements ContentHandler{

    public void startElement(String uri, String localName, String name,
            Attributes atts) throws SAXException {

        System.out.println("当前解析到了:" + name + ",这个标签是开始标签");
        for(int i=0;i<atts.getLength();i++){
            String attname = atts.getQName(i);
            String attvalue = atts.getValue(i);

            System.out.println(attname + "=" + attvalue);
        }

    }

    public void endElement(String uri, String localName, String name)
    throws SAXException {

        System.out.println("当前解析到了:" + name + ",这个标签是结束标签");

    }

    public void characters(char[] ch, int start, int length)
            throws SAXException {

        System.out.println("当前解析到了内容：" + new String(ch,start,length));
    }

    public void endDocument() throws SAXException {
        // TODO Auto-generated method stub

    }

    public void endPrefixMapping(String prefix) throws SAXException {
        // TODO Auto-generated method stub

    }

    public void ignorableWhitespace(char[] ch, int start, int length)
            throws SAXException {
        // TODO Auto-generated method stub

    }

    public void processingInstruction(String target, String data)
            throws SAXException {
        // TODO Auto-generated method stub

    }

    public void setDocumentLocator(Locator locator) {
        // TODO Auto-generated method stub

    }

    public void skippedEntity(String name) throws SAXException {
        // TODO Auto-generated method stub

    }

    public void startDocument() throws SAXException {
        // TODO Auto-generated method stub

    }

    public void startPrefixMapping(String prefix, String uri)
            throws SAXException {
        // TODO Auto-generated method stub

    }

}