<!--Main.Aspx-->
<%@ page language="C#" %>
<%@ import namespace=System.IO %>
<script runat="server">
protected override void OnInit (EventArgs e)
{
int id;
try
{
id = int.Parse (Request.QueryString["id"]);
}
catch
{
throw (new Exception ("頁(yè)面沒有指定id"));
}
string filename=Server.MapPath("statichtml_"+id+".html");
//嘗試讀取已有文件
Stream s = GetFileStream (filename);
if (s != null)//如果文件存在并且讀取成功
{
using (s)
{
Stream2Stream (s, Response.OutputStream);
Response.End ();
}
}
//調(diào)用Main_Execute,并且獲取其輸出
StringWriter sw = new StringWriter ();
Server.Execute ("Main_Execute.aspx", sw);
string content = sw.ToString ();
//輸出到客戶端
Response.Write(content);
Response.Flush();
//寫進(jìn)文件
try
{
using (FileStream fs = new FileStream (filename, FileMode.Create, FileAccess.Write, FileShare.Write))
{
using (StreamWriter streamwriter = new StreamWriter (fs, Response.ContentEncoding))
{
streamwriter.Write (content);
}
}
}
finally
{
//Response.End ();
}
}
static public void Stream2Stream (Stream src, Stream dst)
{
byte[] buf = new byte[4096];
while (true)
{
int c = src.Read (buf, 0, buf.Length);
if(c==0)
return;
dst.Write (buf, 0, c);
}
}
public Stream GetFileStream(string filename)
{
try
{
DateTime dt = File.GetLastWriteTime (filename);
TimeSpan ts=dt - DateTime.Now;
if(ts.TotalHours>1)
return null; //1小時(shí)后過期
return new FileStream (filename, FileMode.Open, FileAccess.Read, FileShare.Read);
}
catch
{
return null;
}
}
</script>
<!--Main_Execute.aspx-->
<%@ page language="C#" %>
<html>
<head runat="server">
<title>Untitled Page</title>
</head>
<body>
ID:
<%=Request.QueryString["id"]%>
</body>
</html>
其中原理是這樣的.
Main_Execute.aspx是生成HTML的頁(yè)面.
現(xiàn)在用Main.aspx來對(duì)它進(jìn)行緩存.
過程如下:
首先根據(jù)頁(yè)面參數(shù)算出文件名.(這個(gè)例子只根據(jù)Request.QueryString["id"]來算)
嘗試讀取緩存的文件.如果成功,那么Response.End();
如果不成功:
使用Server.Execute來調(diào)用Main_Execute.aspx,并且獲取它的結(jié)果內(nèi)容.
得到內(nèi)容后,立刻輸出到客戶端.
最后把內(nèi)容寫進(jìn)文件里,提供給下一次做為緩存度取.
posted on 2007-04-11 17:50
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