SAXParser ne récupère pas les données XML de l'URL

Question

Ma classe implémentée SAXParser qui utilise adresse URL pour traiter les données XML ne retourne pas le résultat. La classe utilise une classe de devise supplémentaire qui stocke à son tour deux variables currId et rate avec setters/getters. Quand je cours ma classe rien ne se montre dans la console de Java. Voici le code:

public class MySAXParser extends DefaultHandler { 

    private static List<Currencies> currencies = new ArrayList<Currencies>(); 
    private static Currencies curr = null; 
    private static String text = null; 

    public static void main(String[] args) { 

     String url = "http://nbt.tj/en/kurs/export_xml.php?date=2016-08-01&export=xmlout"; 

     try { 
      SAXParserFactory spf = SAXParserFactory.newInstance(); 
      SAXParser sp = spf.newSAXParser(); 
      MySAXParser handler = new MySAXParser(); 
      URL uri = new URL(url); 
      sp.parse(new InputSource(uri.openStream()), handler); 
     } catch (Exception ex) { 
      ex.printStackTrace(); 
     } 

     for (Currencies curr : currencies) { 
      System.out.println(curr.toString()); 
     } 

    } 

    public void startElement (String s, String s1, String elementName, Attributes atts) throws SAXException { 
     if (elementName.equalsIgnoreCase("valute")) { 
      curr = new Currencies(); 
      curr.setCurrId(atts.getValue("id")); 
     } 
    } 

    public void endElement (String s, String s1, String element) throws SAXException { 
     if (element.equals("valute")) { 
      currencies.add(curr); 
     } 
     if (element.equalsIgnoreCase("value")) { 
      curr.setRate(Double.parseDouble(text)); 
     } 
    } 

    @Override 
    public void characters (char[] ch, int start, int length) throws SAXException { 
     text = String.copyValueOf(ch, start, length).trim(); 
    } 

} 

Alors, qu'est-ce qui m'a manqué ou mal fait? Toute aide serait appréciée.

Answer 1

Voici ma tentative qui fonctionne très bien avec Java 1.8:

import java.net.URL; 
import java.util.ArrayList; 
import java.util.HashSet; 
import java.util.List; 
import java.util.Set; 
import javax.xml.parsers.SAXParser; 
import javax.xml.parsers.SAXParserFactory; 
import org.xml.sax.Attributes; 
import org.xml.sax.InputSource; 
import org.xml.sax.SAXException; 
import org.xml.sax.helpers.DefaultHandler; 


public class MySAXParser extends DefaultHandler { 

    private List<Currency> currencies = new ArrayList<>(); 
    private Currency curr = null; 
    private StringBuilder sb; 

    public static void main(String[] args) { 

     String url = "http://nbt.tj/en/kurs/export_xml.php?date=2016-08-01&export=xmlout"; 

     try { 
      SAXParserFactory spf = SAXParserFactory.newInstance(); 
      spf.setNamespaceAware(true); 

      SAXParser sp = spf.newSAXParser(); 
      MySAXParser handler = new MySAXParser(); 

      sp.parse(new InputSource(url), handler); 

      for (Currency curr : handler.getCurrencies()) { 
       System.out.println(curr.toString()); 
      } 
     } catch (Exception ex) { 
      ex.printStackTrace(); 
     } 

    } 

    public List<Currency> getCurrencies() { 
     return currencies; 
    } 

    @Override 
    public void startElement(String s, String localName, String elementName, Attributes atts) throws SAXException { 
     if (elementName.equalsIgnoreCase("valute")) { 
      curr = new Currency(); 
      currencies.add(curr); 
      curr.setCurrId(atts.getValue("ID")); 
     } else if (elementName.equalsIgnoreCase("value") || elementName.equalsIgnoreCase("CharCode")) { 
      sb = new StringBuilder(); 
     } 
    } 

    @Override 
    public void endElement(String s, String localName, String elementName) throws SAXException { 
     if (elementName.equalsIgnoreCase("value")) { 
      curr.setRate(Double.parseDouble(sb.toString())); 
      sb = null; 
     } 
     else if (elementName.equalsIgnoreCase("CharCode")) { 
      curr.setCharCode(sb.toString()); 
      sb = null; 
     } 
    } 

    @Override 
    public void characters(char[] ch, int start, int length) throws SAXException { 
     if (sb != null) { 
      sb.append(ch, start, length); 
     } 
    } 

} 

La classe est

public class Currency { 

    private String currId; 

    /** 
    * Get the value of currId 
    * 
    * @return the value of currId 
    */ 
    public String getCurrId() { 
     return currId; 
    } 

    /** 
    * Set the value of currId 
    * 
    * @param currId new value of currId 
    */ 
    public void setCurrId(String currId) { 
     this.currId = currId; 
    } 

     private double rate; 

    /** 
    * Get the value of rate 
    * 
    * @return the value of rate 
    */ 
    public double getRate() { 
     return rate; 
    } 

    /** 
    * Set the value of rate 
    * 
    * @param rate new value of rate 
    */ 
    public void setRate(double rate) { 
     this.rate = rate; 
    } 

    private String charCode; 

    /** 
    * Get the value of charCode 
    * 
    * @return the value of charCode 
    */ 
    public String getCharCode() { 
     return charCode; 
    } 

    /** 
    * Set the value of charCode 
    * 
    * @param charCode new value of charCode 
    */ 
    public void setCharCode(String charCode) { 
     this.charCode = charCode; 
    } 

    @Override 
    public String toString() { 
     return "Currency{" + "currId=" + currId + ", rate=" + rate + ", charCode=" + charCode + '}'; 
    } 

} 

Un exemple de sortie que je reçois est

Currency{currId=840, rate=7.8683, charCode=USD} 
Currency{currId=978, rate=8.7448, charCode=EUR} 
Currency{currId=960, rate=10.9395, charCode=XDR} 
Currency{currId=156, rate=1.1828, charCode=CNY} 
Currency{currId=756, rate=8.075, charCode=CHF} 
Currency{currId=810, rate=0.1146, charCode=RUB} 
Currency{currId=860, rate=0.2655, charCode=UZS} 
Currency{currId=417, rate=1.1643, charCode=KGS} 
Currency{currId=398, rate=0.2234, charCode=KZT} 
Currency{currId=933, rate=3.9424, charCode=BYR} 
Currency{currId=364, rate=0.2617, charCode=IRR} 
Currency{currId=971, rate=1.139, charCode=AFN} 
Currency{currId=586, rate=0.7504, charCode=PKR} 
Currency{currId=949, rate=2.6076, charCode=TRY} 
Currency{currId=934, rate=2.2481, charCode=TMT} 
Currency{currId=826, rate=10.3618, charCode=GBP} 
Currency{currId=36, rate=5.9162, charCode=AUD} 
Currency{currId=208, rate=1.1755, charCode=DKK} 
Currency{currId=352, rate=0.659, charCode=ISK} 
Currency{currId=124, rate=5.9699, charCode=CAD} 
Currency{currId=414, rate=26.004, charCode=KWD} 
Currency{currId=578, rate=0.9193, charCode=NOK} 
Currency{currId=702, rate=5.8215, charCode=SGD} 
Currency{currId=752, rate=0.9136, charCode=SEK} 
Currency{currId=392, rate=0.761, charCode=JPY} 
Currency{currId=944, rate=4.9639, charCode=AZN} 
Currency{currId=51, rate=1.6516, charCode=AMD} 
Currency{currId=981, rate=3.3539, charCode=GEL} 
Currency{currId=498, rate=0.3979, charCode=MDL} 
Currency{currId=980, rate=0.317, charCode=UAH} 
Currency{currId=784, rate=2.1421, charCode=AED} 
Currency{currId=682, rate=2.0979, charCode=SAR} 
Currency{currId=356, rate=1.175, charCode=INR} 
Currency{currId=985, rate=2.0039, charCode=PLN} 
Currency{currId=458, rate=1.9313, charCode=MYR} 
Currency{currId=764, rate=0.2258, charCode=THB}