表示CNN和Reuters RSS源的聚合列表。

/** *************************************************

 * Represents an aggregated list of CNN and Reuters RSS feeds

 * into a single feed.

 *

 * Only works for RSS, not Atom.

 *

 * ************************************************** */


/*from n o w j a   v  a . c o m - 时  代  Java*/

import java.net.URL;

import java.io.PrintWriter;

import java.util.List;

import java.util.ArrayList;

import java.util.Date;

import java.text.DateFormat;

import java.text.SimpleDateFormat;


import com.sun.syndication.feed.synd.SyndFeed;

import com.sun.syndication.feed.synd.SyndEntry;

import com.sun.syndication.feed.synd.SyndFeedImpl;

import com.sun.syndication.io.SyndFeedOutput;

import com.sun.syndication.io.SyndFeedInput;

import com.sun.syndication.io.XmlReader;


public class Feed {

    private SyndFeed feed = null;/** nowjava.com - 时代Java 提 供 **/

    private SyndFeedOutput outFeed = null;


    //Date lastUpdated = new Date(0);

    //Date mostRecent  = new Date(1);

    //set date to minimum value to get all entries.

    //set date to now to get entries from now on-ward.

    Date lastUpdated = new Date();

    Date mostRecent = new Date();


    private List entries = new ArrayList();


    //only RSS feeds work. no Atom feeds.

    String[] urls = {

            "http://rss.cnn.com/rss/cnn_topstories.rss",

            "http://www.reuters.com/rssFeed/topNews",

            "http://feeds.bbci.co.uk/news/rss.xml",

            "http://america.aljazeera.com/content/ajam/articles.rss" };


    public Feed() {

        feed = new SyndFeedImpl();

        feed.setFeedType("rss_1.0");

        /*

        valid values are:   rss_0.9, rss_0.91U, rss_0.91N, rss_0.92, rss_0.93,

                            rss_0.94, rss_1.0, rss_2.0 & atom_0.3

         */


        feed.setTitle("RSS Aggregated Feed");

        feed.setDescription("Combine RSS feeds for Twitter Bot.");

        feed.setAuthor("None");

        feed.setLink("http://www.example.com");

    }


    /** *************************************************

     * This creates a news list with all the newest entries since

     * last run of parseFeed().

     *

     * ************************************************** */

    public void parseFeed() {

        entries = new ArrayList();

        feed.setEntries(entries);


        for (int i = 0; i < urls.length; ++i) {

            URL inputURL = null;

            SyndFeedInput input = null;

            SyndFeed inFeed = null;


            try {

                inputURL = new URL(urls[i]);

                input = new SyndFeedInput();

                inFeed = input.build(new XmlReader(inputURL));


                //create a whole new list and add the new items to it.

                for (SyndEntry entry : (List<SyndEntry>) inFeed

                        .getEntries()) {

                    if (entry.getPublishedDate().after(lastUpdated)) {

                        entries.add(entry);


                        //find the most recent entry (like finding the max value)

                        if (entry.getPublishedDate().after(mostRecent)) {

                            mostRecent = entry.getPublishedDate();

                        }

                    }

                }


            } catch (Exception ex) {

                ex.printStackTrace();

                System.out.println("ERROR: " + ex.getMessage());

            }

        }

        lastUpdated = mostRecent;

    }


    public boolean isUpdated() {

        return !entries.isEmpty();

    }


    public Date getLastUpdate() {

        return lastUpdated;

    }


    public List<SyndEntry> getEntries() {

        return entries;

    }


    public void output() {

        try {

            outFeed = new SyndFeedOutput();

            outFeed.output(feed, new PrintWriter(System.out), true);

        } catch (Exception ex) {

            ex.printStackTrace();

            System.out.println("ERROR: " + ex.getMessage());

        }

    }


    //tester/client

    public static void main(String args[]) {

        Feed myfeed = new Feed();

        DateFormat df = new SimpleDateFormat("M-d HH:mm:ss z");


        while (true) {

            myfeed.parseFeed();

            if (myfeed.isUpdated()) {

                System.out.println("Most recent entry: "