weatherservice.java

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/*
 * WeatherService.java
 *
 * Created on 2006年5月5日, 下午9:22
 *
 * To change this template, choose Tools | Template Manager
 * and open the template in the editor.
 */

package com.j2medev.chapter4.weather;

import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Vector;
import javax.xml.parsers.*;
import org.xml.sax.*;
import org.xml.sax.helpers.DefaultHandler;

public class WeatherService {
    
    private String host = "http://xml.weather.yahoo.com/forecastrss?";
    public WeatherService() {
    }
    
    public String getWeather(String location,String style){
        try{
            URL url = new URL(host+"p="+location+"&u="+style);
            InputStream is = url.openStream();
            SAXParserFactory factory = SAXParserFactory.newInstance();
            SAXParser parser = factory.newSAXParser();
            WeatherHandler handler = new WeatherHandler();
            parser.parse(is,handler);
            return handler.getWeather();
            
        }catch(MalformedURLException ex){
            ex.printStackTrace();
        }catch(IOException ex){
            ex.printStackTrace();
        }catch(ParserConfigurationException ex){
            ex.printStackTrace();
        }catch(SAXException ex){
            ex.printStackTrace();
        }
        return null;
    }
    
    class WeatherHandler extends DefaultHandler{

        Location location = new Location();
        Unit unit = new Unit();
        Vector v = new Vector();
        
        public String getWeather(){
            StringBuffer sb = new StringBuffer();
            for(int i = 0;i<v.size();i++){
                sb.append(((Forecast)v.get(i)).toString());
            }
            return location.toString()+sb.toString();
        }

        public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
            if("yweather:location".equals(qName)){
                for(int i = 0;i<attributes.getLength();i++){
                    location.set(i,attributes.getValue(i));
                }
            }else if("yweather:units".equals(qName)){
                for(int i = 0;i<attributes.getLength();i++){
                    unit.set(i,attributes.getValue(i));
                }
            }else if("yweather:forecast".equals(qName)){
                Forecast forecast = new Forecast();
                for(int i = 0;i<attributes.getLength();i++){
                    forecast.set(i,attributes.getValue(i));
                }
                forecast.setUnit(unit);
                v.addElement(forecast);
            }
        }
    }
}