Web2.0时代，RSS你会用了吗？RSS技术实现总结

如见Web2.0被吵的如火如荼，同时也有很多的评论褒贬不一。有人说Web2.0就是“一帮人在看皇帝的新装而已”。也有人说Web2.0将是一场变革。无论这些争论有没有价值，但我相信，存在就有它的必然性。也许Web2.0更像是一种商业模式，一个观念的变革而非技术。

不管怎样，它来了，你准备好了吗？

说到Web2.0，就会提到Blog、TAG、SNS、RSS、wiki这些软件应用和xml、ajax等这些新理论和技术实现。

RSS毋容置疑就是其重要的应用之一。

那么什么是RSS？它到底有什么用呢？

RSS是站点与站点之间共享内容的一种简易方式(也称为“聚合内容”)，通常被用于新闻和其他按顺序排列的网站，例如Blog网站。网站提供RSS输出，有利于让用户发现网站内容的更新。网站用户可以在客户端借助于类似新闻资讯阅读器等支持RSS的新闻聚合工具软件，在不打开网站内容页面的情况下阅读支持RSS输出的网站内容。

RSS是基于XML的一种形式。并且所有的RSS文件都要遵守万维网联盟(W3C)站点发布的XML 1.0规范。具体格式可以查一下 RSS 2.0规范，这里就不再重复粘贴了。

下面是我总结的几种RSS的技术实现代码：

1.在线生成RSS聚合页。

(1)创建Rss.aspx

<%@ Page language="c#" Codebehind="Rss.aspx.cs" AutoEventWireup="false" Inherits="LiTianPing.Rss" %>

只留下这一行，其余的都删掉。

(2)后台代码实现方式1；Rss.aspx.cs

private void Page_Load(object sender, System.EventArgs e)

{

Response.ContentType="text/xml";

Response.Write(GetRSS());

}

/// <summary>

/// 取得聚合文章

/// </summary>

/// <returns></returns>

public string GetRSS()

{

News t=new News();//自己的业务类

DataSet ds=t.GetListByClass(1);//根据类别得到数据

StringBuilder strCode=new StringBuilder();

strCode.Append("<?xml version=/"1.0/" encoding=/"utf-8/" standalone=/"yes/" ?>");

strCode.Append("<rss version=’’’’2.0’’’’ xmlns:dc=/"http://purl.org/dc/elements/1.1//"");

strCode.Append(" xmlns:trackback=/"http://madskills.com/public/xml/rss/module/trackback//" ");

strCode.Append(" xmlns:wfw=/"http:/

wellformedweb.org/CommentAPI//" xmlns:slash=/"http://purl.org/rss/1.0/modules/slash//">");

strCode.Append("<channel>");

strCode.Append("<title>李天平RSSDemo</title>");

strCode.Append("<link>http://"+Request.ServerVariables["SERVER_NAME"]+"</link> ");

strCode.Append("<description>天道酬勤</description> ");

strCode.Append("<copyright>Copyright 2005</copyright> ");

foreach(DataRow row in ds.Tables[0].Rows)

{

string Id=row["Id"].ToString();

string title=row["title"].ToString();

string description=row["description"].ToString();

string pubdate=row["pubdate"].ToString();

string ClassId=row["ClassId"].ToString();

//string author=row["author"].ToString();

strCode.Append("<item>");

strCode.Append("<title>"+title+"</title>");

strCode.Append("<link>http://"+Request.ServerVariables["SERVER_NAME"]+"/NewsShow.aspx?ID="+Id+"</link>");

strCode.Append("<subject>"+description+"</subject>");

strCode.Append("<description><![CDATA["+description+"]]></description>");

strCode.Append("<PubDate>"+pubdate+"</PubDate>");

strCode.Append("<category>"+ClassId+"</category>");

strCode.Append("</item>");

}

strCod

.Append("</channel>");

strCode.Append("</rss>");

return strCode.ToString();

}

(3) XmlTextWriter实现方式2；Rss.aspx.cs

string xmlDoc="rss.xml";

private void Page_Load(object sender, System.EventArgs e)

{

xmlDoc=Server.MapPath(".")+xmlDoc;

GetRSS2();

XmlDocument doc= new XmlDocument();

doc.Load(xmlDoc);

Response.ContentType = "text/xml";

doc.Save(Response.Output);

}

/// <summary>

/// 取得聚合文章

/// </summary>

/// <returns></returns>

public void GetRSS2()

{

News t=new News();

DataSet ds=t.GetListByClass(1);

XmlTextWriter writer = new XmlTextWriter(xmlDoc,Encoding.UTF8);

writer.Formatting = Formatting.Indented;

writer.WriteStartDocument(true);

writer.WriteComment("RSS页的实现");

writer.WriteStartElement("rss");

writer.WriteAttributeString("version","2.0");

writer.WriteStartElement("channel");

writer.WriteStartElement("title");

writer.WriteString("李天平RSSDemo");

writer.WriteEndElement();

writer.WriteStartElement("link");

writer.WriteString("http://"+request.servervariables["server_name/"]);

writer.WriteEndElement();

writer.W

iteStartElement("description");

writer.WriteString("天道酬勤");

writer.WriteEndElement();

writer.WriteStartElement("copyright");

writer.WriteString("Copyright 2005");

writer.WriteEndElement();

writer.WriteStartElement("language");

writer.WriteString("zh-cn");

writer.WriteEndElement();

foreach(DataRow row in ds.Tables[0].Rows)

{

string Id=row["Id"].ToString();

string title=row["title"].ToString();

string description=row["description"].ToString();

string pubdate=row["pubdate"].ToString();

string ClassId=row["ClassId"].ToString();

//string author=row["author"].ToString();

writer.WriteStartElement("item");

writer.WriteStartElement("title");

writer.WriteString(title);

writer.WriteEndElement();

writer.WriteStartElement("link");

writer.WriteString(" writer.WriteCData(description);

writer.WriteEndElement();

writer.WriteStartElement("pubDate");

writer.WriteString(pubdate);

writer.WriteEndElement();

writer.WriteStartElement("category");

writer.WriteString(ClassId);

writer.WriteEndElement();

writer.WriteEndElement();

}

writer.WriteEndElement();

writer.WriteEndElement();

&

bsp;writer.Flush();

writer.Close();

}

2.在线RSS阅读获取。

页面代码：

<P style="FONT-SIZE: 11px">

Feed种子：<asp:TextBox id="FeedUrl" runat="server" Width="440px"& gt;</asp:TextBox><BR>

显示条数：<asp:TextBox id="Num" runat="server" Width="48px">< /asp:TextBox></P>

<P style="FONT-SIZE: 11px">

<asp:Button id="GetFeed" runat="server" Text="获得RSS">< /asp:Button><BR>

<BR>

<asp:Label id="RssFeed" runat="server"></asp:Label></P>

后台代码：

/// <summary>

/// 获得要显示的Feed种子数据

/// </summary>

/// <param name="RssUrl"></param>

/// <param name="showNewsCount"></param>

/// <returns></returns>

public string LoadRSS(string RssUrl, int showNewsCount)

{

string strRssList = "";

string strMsg;

try

{

XmlDocument objXMLDoc = new XmlDocument();

objXMLDoc.Load(RssUrl);

XmlNodeList objItems = objXMLDoc.GetElementsByTagName("item");

if(showNewsCount > 30)

showNewsCount = 10;

if(showNewsCount < 1)

showNewsCount = objItems.Count;

&

bsp; string title="";

string link="";

int i;

if(objXMLDoc.HasChildNodes == true)

{

i = 1;

foreach(XmlNode objNode in objItems)

{

if(i<=showNewsCount)

{

if(objNode.HasChildNodes == true)

{

XmlNodeList objItemsChild = objNode.ChildNodes;

foreach(XmlNode objNodeChild in objItemsChild)

{

switch(objNodeChild.Name)

{

case "title":

title = objNodeChild.InnerText;

break;

case "link":

link = objNodeChild.InnerText;

break;

}

}

i = i+1;

strRssList += "<a href=" + link +" target=_blank>" + title + "</a><br>";

} &

bsp;

}

}

}

strMsg = strRssList;

}

catch

{

strMsg = "RSS Feed 源数据出错！";

}

return strMsg;

}

//获取按钮,获取指定RSS

private void GetFeed_Click(object sender, System.EventArgs e)

{

if(FeedUrl.Text == "")//RSS地址

{

RssFeed.Text = "信息源不能为空，您可刷新重试或联系管理员！";

return ;

}

RssFeed.Text = LoadRSS(FeedUrl.Text,Convert.ToInt32(Num.Text)); // 获取指定数目

}

3.无刷新动态更新的在线RSS阅读获取

<%@ Page language="c#" Codebehind="XmlHttp.aspx.cs" AutoEventWireup="false" Inherits="LiTianPing.XmlHttp" %>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >

<HTML>

<HEAD>

<title>XmlHttp</title>

<meta name="GENERATOR" Content="Microsoft Visual Studio .NET 7.1">

<meta name="CODE_LANGUAGE" Content="C#">

<meta name="vs_defaultClientScript" content="JavaScript">

<meta name="vs_targetSchema" content="http://schemas.microsoft.com/intellisense/ie5">

<style>td { font-size: 9pt}

</style>

<script>

<!--

var oDiv

var xh

function

getXML()

{

xh =new ActiveXObject("Microsoft.XMLHTTP");

oDiv = document.getElementById("rssitem");

oDiv.style.display= "";

try

{

//如果是本地改成下面语句直接读取

//xh.open("GET","/Rss.aspx",false);

xh.open("GET","Http://ltp.cnblogs.com/Rss.aspx",false);

xh.send(null);

loadData(xh,oDiv);

}

catch(e)

{

error(oDiv);

}

}

function loadData(xh,oDiv)

{

if (xh.readyState == 4)

{

xml = xh.responsexml;

var i;

var nodes = xml.selectNodes("/rss/channel/item");

var bloglink = xml.selectSingleNode("/rss/channel/link").text;

oDiv.innerHTML = "";

var html;

for(i=0;i<nodes.length;i++)

{

html += "<div >";

html += " <div >";

html += " <a class=font1 href=’’’’" +nodes[i].selectSingleNode("link").text + "’’’’ target=’’’’_blank’’’’>" + nodes[i].selectSingleNode("title").text +"</a><BR><BR>";

html += &qu

t; </div>";

html += " <div >";

html += " " +nodes[i].selectSingleNode("description").text;

html += " </div>"

//html += " </div>";

html += "</div><hr>";

}

oDiv.innerHTML = html;

}

else

{

error(oDiv);

}

}

function error(oDiv)

{

oDiv.innerHTML = "载入失败";

}

-->

</script>

</HEAD>

<body MS_POSITIONING="GridLayout" onload="window.setTimeout(’’’’getXML()’’’’,200);">

<form id="Form1" method="post" runat="server">

<div align=center>

<table cellpadding="0" cellspacing="0" border="0" width="80%">

<tr>

<td>

<div id="rssitem" style="WIDTH:80%">数据载入中...</div& gt;

</td>

</tr>

</table>

</div>

</form>

</body>

</HTML>