开发RSS聚合的开源框架

最近公司要开发一个基与java的RSS阅读器，但是时间紧，在网上找个了一个开源的框架Rome,Rome并不是指罗马。不要误会，这里介绍的rome为一个开源java框架，可以在www.java.net上找到它，它是为RSS聚合而开发的一个框架，让你可以快速的开发基于java的RSS阅读，发布器，支持

• RSS 0.91 Netscape
• RSS 0.91 Userland
• RSS 0.92
• RSS 0.93
• RSS 0.94
• RSS 1.0
• RSS 2.0
• Atom 0.3
• Atom 1.0

  等标准。你也可以自己扩展他的Module，让他解析你自己定义的XML格式。可以说它是一种用途很广的框架，在使用它之前。你必须下载JDOM开发包，因为它是用JDOM解析XML的。

在Rome中主要包裹下面几个包

com.sun.syndication.feed

com.sun.syndication.feed.atom

与获得atom中各个节点的数据

com.sun.syndication.feed.module

modeule为各个数据模型层。可以自己扩展

com.sun.syndication.feed.rss

用与获得RSS中各个相对应的XML节点中的值

com.sun.syndication.feed.sse
com.sun.syndication.feed.synd

此包为写成RSS格式的XML设置个节点的属性
com.sun.syndication.io

此包为输入输出流。

它的UML图

                                   图1

下面是一个例子，功能是生成RSS格式的XML

public class FeedWriter {

    private static final String DATE_FORMAT = "yyyy-MM-dd";

    public static void main(String[] args) {
        boolean ok = false;
        if (args.length==2) {
            try {
                String feedType = args[0];
                String fileName = args[1];

                DateFormat dateParser = new SimpleDateFormat(DATE_FORMAT);

                SyndFeed feed = new SyndFeedImpl();  //feed流
                feed.setFeedType(feedType);                   //设置rss版本

                feed.setTitle("Sample Feed (created with Rome)");  //<title>设置标题
                feed.setLink(http://www.csdn.net);                               //<link>
                feed.setDescription("This feed has been created using Rome (Java syndication utilities");

                List entries = new ArrayList();
                SyndEntry entry;
                SyndContent description;

                entry = new SyndEntryImpl();                                 //子节点
                entry.setTitle("Rome v1.0");
                entry.setLink(http://www.csdn.net);
                entry.setPublishedDate(dateParser.parse("2004-06-08"));
                description = new SyndContentImpl();
                description.setType("text/plain");
                description.setValue("Initial release of Rome");
                entry.setDescription(description);
                entries.add(entry);

                entry = new SyndEntryImpl();
                entry.setTitle("Rome v2.0");
                entry.setLink(http://ww.csdn.net);
                entry.setPublishedDate(dateParser.parse("2004-06-16"));
                description = new SyndContentImpl();            //描述
                description.setType("text/xml");
                description.setValue("Bug fixes, <xml>XML</xml> minor API changes and some new features");
                entry.setDescription(description);
                entries.add(entry);

                entry = new SyndEntryImpl();
                entry.setTitle("Rome v3.0");
                entry.setLink("http://www.csdn.net");
                entry.setPublishedDate(dateParser.parse("2004-07-27"));
                description = new SyndContentImpl();
                description.setType("text/html");
                description.setValue("<p>More Bug fixes, mor API changes, some new features and some Unit testing</p>"+
                                     "<p>For details check the <a href=\"http://www.csdn.net\">Changes Log</a></p>");
                entry.setDescription(description);
                entries.add(entry);

                feed.setEntries(entries);                             //设置子节点

                Writer writer = new FileWriter(fileName);
                SyndFeedOutput output = new SyndFeedOutput();
                output.output(feed,writer);                        //写到文件中去
              
                writer.close();

                System.out.println("The feed has been written to the file ["+fileName+"]");

                ok = true;
            }
            catch (Exception ex) {
                ex.printStackTrace();
                System.out.println("ERROR: "+ex.getMessage());
            }
        }

        if (!ok) {
            System.out.println();
            System.out.println("FeedWriter creates a RSS/Atom feed and writes it to a file.");
            System.out.println("The first parameter must be the syndication format for the feed");
            System.out.println("  (rss_0.90, rss_0.91, rss_0.92, rss_0.93, rss_0.94, rss_1.0 rss_2.0 or atom_0.3)");
            System.out.println("The second parameter must be the file name for the feed");
            System.out.println();
        }
    }

}     就这么多了。第一次写blog写的不好。大家不要砸砖头：）