java使用SAX解析xml详解编程语言

import java.io.File; 
import java.util.LinkedList; 
import java.util.List; 
 
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 ParseXMLFileWithSAX extends DefaultHandler { 
 
private StringBuffer buffer = new StringBuffer(); 
 
    private static String responseCode; 
    private static String date; 
    private static String title; 
 
    private static Currency currency; 
    private static Rates rates; 
 
    public static void main(String[] args) throws Exception { 
 
        DefaultHandler handler = new ParseXMLFileWithSAX(); 
 
        SAXParserFactory factory = SAXParserFactory.newInstance(); 
        factory.setValidating(false); 
 
        SAXParser parser = factory.newSAXParser(); 
 
        parser.parse(new File("in.xml"), handler); 
 
        System.out.println("Response Code:" + responseCode); 
        System.out.println("Date:" + date); 
        System.out.println("Title:" + title); 
        System.out.println("Rates:"); 
 
        for (Currency curr : rates.currencies) { 
            System.out.println("/tCode:" + curr.code + " - Rate:" + curr.rate); 
        } 
 
    } 
 
    private static class Currency { 
        public String code; 
        public String rate; 
    } 
 
    private static class Rates { 
        public List<Currency> currencies = new LinkedList<Currency>(); 
    } 
 
    @Override 
    public void startElement(String uri, String localName, String qName, 
            Attributes attributes) throws SAXException { 
 
        buffer.setLength(0); 
 
        if (qName.equals("response")) { 
            responseCode = attributes.getValue("code"); 
        } 
        else if (qName.equals("date")) { 
            date = ""; 
        } 
        else if (qName.equals("title")) { 
            title = ""; 
        } 
        else if (qName.equals("rates")) { 
            rates = new Rates();  
        } 
        else if (qName.equals("currency")) { 
            currency = new Currency();  
        } 
 
    } 
 
    @Override 
    public void endElement(String uri, String localName, String qName)throws SAXException { 
 
        if (qName.equals("date")) { 
            date = buffer.toString(); 
        } 
        else if (qName.equals("title")) { 
            title = buffer.toString(); 
        } 
        else if (qName.equals("currency")) { 
            rates.currencies.add(currency); 
        } 
        else if (qName.equals("code")) { 
            currency.code = buffer.toString(); 
        } 
        else if (qName.equals("rate")) { 
            currency.rate = buffer.toString(); 
        } 
 
    } 
 
    public void characters(char[] ch, int start, int length) { 
        buffer.append(ch, start, length); 
    } 
 
}

输入xml文件:

<?xml version="1.0" encoding="UTF-8" ?> 
<response code="200"> 
    <date>2008-11-07</date> 
    <title>Exchange rates for 2008-11-07</title> 
    <rates> 
        <currency> 
            <code>EUR</code> 
            <rate>1.220</rate> 
        </currency> 
        <currency> 
            <code>USD</code> 
            <rate>1.275</rate> 
        </currency> 
    </rates> 
</response>

输出：

Response Code:200 
Date:2008-11-07 
Title:Exchange rates for 2008-11-07 
Rates: 
    Code:EUR - Rate:1.0 
    Code:USD - Rate:1.275600