Parse a RSS XML fileTag(s): XML


In a previous HowTo, we saw how to create a RSS feed using commons.digester or ROME packages. In this HowTo, we are parsing a given feed using the packages.
Parsing a feed with Apache Commons Digester
NOTE: See this HowTo for the required jars.
import org.apache.commons.digester.rss.Channel;
import org.apache.commons.digester.rss.Item;
import org.apache.commons.digester.rss.RSSDigester;

import java.net.HttpURLConnection;
import java.net.URL;

public class ParseRSSFeedUsingCommons {
    public static void main(String args[]) throws Exception {
        RSSDigester digester=new RSSDigester();
        String feed = "http://www.rgagnon.com/feed.xml";
        URL url=new URL(feed);
        HttpURLConnection httpSource=
            (HttpURLConnection)url.openConnection();
        Channel channel=
            (Channel)digester.parse(httpSource.getInputStream());
        if (channel==null) {
            throw new Exception("can't communicate with " + url);
        }

        Item rssItems[]=channel.findItems();
        for (int i=0;i<rssItems.length;i++) {
           System.out.println(rssItems[i].getTitle());
           System.out.println(rssItems[i].getLink());
           System.out.println(rssItems[i].getDescription());
           System.out.println();
        }
        /*
              to parse from a file instead of a URL

              import java.io.FileInputStream;
              ...
              String feed = "feed.xml"
              FileInputStream fis = new FileInputStream(feed);
              Channel channel=(Channel)digester.parse(fis);
              ...
       */
    }
}
the output
JS: Resize an IFRAME based on its content
http://www.rgagnon.com/jsdetails/js-0129.html
Using the onLoad event, resize the IFRAME according to its content

Java: Communicate between threads using a Queue
http://www.rgagnon.com/javadetails/java-0555.html
BlockingQueue (Java 5) is designed to work in a multi-threaded world

JDBC: Escape special character in a LIKE clause
http://www.rgagnon.com/javadetails/java-0554.html
How to use LIKE clause wildcards as literals
...
Parsing a feed with ROME
NOTE: See this HowTo for the required jars.
import com.sun.syndication.feed.synd.*;
import com.sun.syndication.feed.synd.SyndFeed;
import com.sun.syndication.io.SyndFeedInput;
import com.sun.syndication.io.XmlReader;

import java.net.URL;
import java.util.List;
import java.util.Iterator;

public class ParseRSSFeedUsingRome {
  public static void main(String args[]) throws Exception {
    String feed = "http://www.rgagnon.com/feed.xml";

    URL feedUrl = new URL(feed);

    SyndFeedInput input = new SyndFeedInput();
    SyndFeed sf = input.build(new XmlReader(feedUrl));

    List entries = sf.getEntries();
    Iterator it = entries.iterator();
    while (it.hasNext()) {
      SyndEntry entry = (SyndEntry)it.next();
      System.out.println(entry.getTitle());
      System.out.println(entry.getLink());
      SyndContent description = entry.getDescription();
      System.out.println(description.getValue());
      System.out.println();
    }
    /*
       to parse from a file instead of a URL

       import java.io.FileInputStream;
       ...
       String feed = "feed.xml"
       FileInputStream fis = new FileInputStream(feed);

       SyndFeedInput input = new SyndFeedInput();
       SyndFeed sf = input.build(new XmlReader(fis));
    */
  }
}

RSS-UTIL.TLD
A Sun article about a JSP Tag Library to parse a RSS feed. http://java.sun.com/developer/technicalArticles/javaserverpages/rss_utilities/
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