Want to have RSS feeds in your Java application? Try Rome..

"Rome is an open source library for generating, parsing and manipulating RSS and Atom feeds. It supports different RSS and Atom feed formats such as Atom 0.3, and Atom 1.0, RSS 0.90, RSS 0.91 Netscape, RSS 0.91 Userland, RSS 0.92, RSS 0.93, RSS 0.94, RSS 1.0 and RSS 2.0."

A couple months back, I got to use the Rome library to implement RSS in Archiva. What I liked about Rome is how it’s so easy to understand and use. To generate an RSS feed, you basically just need to be familiar with these three classes: SyndFeed, SyndEntry and SyndContent. These three are Java interfaces with the following concrete implementations: SyndFeedImpl, SyndEntryImpl and SyndContentImpl respectively. Here’s a short example on how you can generate a RSS 2.0 feed:

SyndFeed feed = new SyndFeedImpl(); // create the feed
Date publishDate = new Date( System.currentTimeMillis() );

feed.setTitle( "Techblog.ph RSS Feeds" );
feed.setDescription( "RSS feeds of blog entries from Techblog.ph" );
feed.setLanguage( "en-us" );
feed.setPublishedDate( publishDate );
feed.setFeedType( "rss_2.0" ); // set the type of your feed

List<SyndEntry> entries = new ArrayList<SyndEntry>();

SyndEntry entry = new SyndEntryImpl(); // create a feed entry
entry.setTitle( "Generating RSS Feeds with Rome" );
entry.setPublishedDate( publishDate );

SyndContent content = new SyndContentImpl(); // create the content of your entry
content.setType( "text/plain" );
content.setValue( "Want to have RSS feeds in your Java application? Try Rome….." );

entry.setDescription( content );
entries.add( entry );
feed.setEntries( entries ); // you can add multiple entries in your feed

For the published date, make sure that you update it whenever you have a new entry and publish the feed so that the reader knows there were changes/updates in your feed.

Now, to publish your feed.. you can write it into a file (example, write it to rss.xml) which the feed reader checks for updates or you can generate the feed by request (like how it is done in Archiva). If you are publishing your feeds by writing it on a file, you might need to read the file into a SyndFeed before adding new entries as shown below:

SyndFeedInput input = new SyndFeedInput();
SyndFeed feed = input.build( new XmlReader( outputFile ) );

To learn more about the Rome library, check out the Rome API.

Posted on 08.26.08 to Tech blogs by oching. Tagged archiva, atom, java, rome, rss. Subscribe to follow comments on this post. 3 comments. Add your thoughts or trackback from your own site.

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