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rss的在java中的出现，大家对其褒贬不一，但是他毕竟是出现了，并且有很多大型的网站都在用它，不论我们是抵触也好，接受也罢，但很有可能在某一天你的老板会让你用到这项技术。我们就要具备。
在web当中应用，要有以下两个开发包，
jdom.jar：JDOM开源项目中（http://www.jdom.org/）
rome.jar : ROME开源项目中（http://wiki.java.net/bin/view/Javawsxml/Rome）
关于rss在javaweb中的应用，分为两个步骤实施：
1.生成rss格式的xml文件：
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();
}
}
}
2.对此xml文件的读取：
<%@page contentType="text/html"%>
<%@page pageEncoding="UTF-8"%>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Sina News</title>
</head>
<body>
<%
java.util.Properties systemSettings = System.getProperties();
systemSettings.put("http.proxyHost", "mywebcache.com");
systemSettings.put("http.proxyPort", "8080");
System.setProperties(systemSettings);
String urlStr = "http://rss.sina.com.cn/news/marquee/ddt.xml";
java.net.URLConnection feedUrl = new java.net.URL(urlStr).openConnection();
feedUrl.setRequestProperty("User-Agent", "Mozilla/4.0 (compatible; MSIE 5.0; Windows NT; DigExt)");
com.sun.syndication.io.SyndFeedInput input = new com.sun.syndication.io.SyndFeedInput();
com.sun.syndication.feed.synd.SyndFeed feed = input.build(new com.sun.syndication.io.XmlReader(feedUrl));
%>
<div align="center">
<h1><%=feed.getTitle()%></h1>
<table border=1 cellpadding=3 width="700">
<tr>
<th>Number</th>
<th>Title</th>
<th>Time</th>
</tr>
<%
java.util.List list = feed.getEntries();
for (int i=0; i< list.size(); i++) {
com.sun.syndication.feed.synd.SyndEntry entry = (com.sun.syndication.feed.synd.SyndEntry)list.get(i);
%>
<tr>
<td><%=i+1%></td>
<td><a href="<%=entry.getLink()%>"><%=entry.getTitle()%></a></td>
<td><%=entry.getPublishedDate()%></td>
</tr>
<%}%>
</table>
</div>
<br>
</body>
</html>
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