asp。net缓存

Asp.net 缓存Cache功能已经是很常见的功能了，网络上面这种相关的文章也非常之多，我这里所要讲的缓存并不是.NET所提供的缓存，而是过通文件方式来存放的。这样可以很好的减少服务器资源。
先看一下我做这个的缓存流程图：

如上图所示，其实程序就是在Page_Load的时候做一下判断，是否有缓存文件存在或者缓存是否过期（过期的判断是通过文件的最后修改日期来处理的），如果没有，它将会去读取当前页的页面HTML代码，并用当前页的文件名保存成一个文件缓存。下次再打开此页的时候就会去读取存下来的缓存文件的内容，并同时中断PageLoad后边的方式，从页实现很有效的使用很方便的缓存机制。

以下是部分代码
default.aspx.cs (一个普通的服务端页面)

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;

namespace cacheweb
{
 /// <summary>
 /// _default 的摘要说明。
 /// </summary>
 public class _default : BasePage
 {
 private void Page_Load(object sender, System.EventArgs e)
 {
 // 在此处放置用户代码以初始化页面
 if(this.CacheProgress())
 {
 return ;
 }

 initPage();
 }

 private void initPage()
 {
 Response.Write("FileCache V0.1 - 文件缓存方式的功能演示 ");
 Response.Write("Wathon Team ");
 Response.Write("<a href=\"http://www.wathon.com\">http://www.wathon.com</a> ");
 Response.Write("<a href=\"http://www.cnblogs.com/huacn/archive/2007/11/07/aspnet_page_cache_file.html\">参数讨论</a> ");
 Response.Write("以下是上次缓存的时间： ");
 Response.Write(DateTime.Now.ToLocalTime()+" ");
 Response.Write(DateTime.Now.ToLongDateString()+" ");
 Response.Write(DateTime.Now.ToLongTimeString()+" ");
 Response.Write(DateTime.Now.ToOADate()+" ");
 Response.Write(DateTime.Now.ToShortDateString()+" ");
 Response.Write(DateTime.Now.ToUniversalTime()+" ");
 Response.Write(DateTime.Now.ToShortTimeString()+" ");
 }

 #region Web 窗体设计器生成的代码
 override protected void OnInit(EventArgs e)
 {
 //
 // CODEGEN: 该调用是 ASP.NET Web 窗体设计器所必需的。
 //
 InitializeComponent();
 base.OnInit(e);
 }

 /// <summary>
 /// 设计器支持所需的方法 - 不要使用代码编辑器修改
 /// 此方法的内容。
 /// </summary>
 private void InitializeComponent()
 {
 this.Load += new System.EventHandler(this.Page_Load);
 }
 #endregion
 }
}

BasePage.cs (页面的基类)

using System;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Net;
using System.Text;
using System.IO;
using cacheweb.App_code.FileCache;

/// <summary>
/// 页面的基类
/// Wathon Team.
/// By Json Lee 2007-11-07
/// http://www.wathon.com
/// </summary>
public class BasePage:Page
{
 /// <summary>
 /// 自动处理页面缓存
 /// 当返回true表示要中断页面的所有内容
 /// false不要做处理
 /// </summary>
 /// <returns></returns>
 protected bool CacheProgress()
 {
 if(Request.QueryString["serverget"] == "1")
 {
 return false;
 }

 string strContent = "";
 string url = Request.Url.ToString();
 Caches caches = new Caches();

 if(caches.ExistCache(url))
 {
 //取缓存
 strContent = caches.GetCache(url);
 }
 else
 {
 //取当前页面的HTML
 strContent = GetUrlResponse(url);
 //存缓存
 caches.SetCache(strContent,url);
 }

 //输出内容
 Response.Write(strContent);
 Response.End();
 return true;
 }


 /// <summary>
 /// 取得URL的页面内容
 /// </summary>
 /// <param name="p_PageUrl">URL地址要完整的</param>
 /// <returns></returns>
 private string GetUrlResponse(string p_PageUrl)
 {
 //给URL加入ServerGet的参数，以防止重复循环
 if(p_PageUrl.IndexOf("?") > 0)
 {
 p_PageUrl += "&serverget=1" ;
 }
 else
 {
 p_PageUrl += "?serverget=1" ;
 }

 WebRequest webrequest = WebRequest.Create(p_PageUrl);
 string strContent = "";
 try
 {
 WebResponse webresponse = webrequest.GetResponse();
 Stream stream = webresponse.GetResponseStream();
 StreamReader sr = new StreamReader(stream, Encoding.UTF8);

 strContent = sr.ReadToEnd();
 }
 catch (Exception ex)
 {
 throw new Exception(ex.ToString());
 }

 return strContent;
 }

}

CacheBase.cs (Cache的基类)

using System;
using System.IO;

namespace cacheweb.App_code.FileCache
{
 /// <summary>
 /// Cache基类
 /// 包括了一些常用的方法和配置
 /// Wathon Team.
 /// By Json Lee 2007-11-07
 /// http://www.wathon.com
 /// </summary>
 public abstract class CacheBase
 {
 /// <summary>
 /// 文件统一的编码格式
 /// </summary>
 private System.Text.Encoding _FileEncoding = System.Text.Encoding.UTF8;

 /// <summary>
 /// Cache文件存放基本目录
 /// </summary>
 private string _FilePath = @"D:\CacheFiles\Test\";

 /// <summary>
 /// 文件扩展名
 /// </summary>
 private string _FileExt = ".phtml";

 /// <summary>
 /// 文件缓存的时间单位分
 /// </summary>
 private int _FileCacheMiniutes = 2;

 /// <summary>
 /// 检查文件是否存在
 /// </summary>
 /// <param name="p_FileName">文件名，不带路径，不带扩展名</param>
 /// <returns></returns>
 protected bool ExistFile(string p_FileName)
 {
 bool resultValue = false;
 try
 {
 string strFileName = _FilePath + p_FileName + _FileExt;
 if(File.Exists(strFileName))
 {
 //文件是否过期
 DateTime tmFile = File.GetLastWriteTime(strFileName);
 DateTime tmNow = DateTime.Now;
 TimeSpan ts = tmNow - tmFile;
 if(ts.TotalMinutes < _FileCacheMiniutes)
 {
 resultValue = true;
 }
 }

 }
 catch(Exception ex)
 {
 throw new Exception(ex.ToString());
 }

 return resultValue;
 }

 /// <summary>
 /// 读文本文件
 /// </summary>
 /// <param name="p_FileName">文件名，不带路径，不带扩展名</param>
 /// <param name="p_Content">返回用于存放内容的变量</param>
 /// <returns></returns>
 protected bool ReadFile(string p_FileName,ref string p_Content)
 {
 bool resultValue = false;
 if(! this.ExistFile(p_FileName))
 {
 return resultValue;
 }


 try
 {
 System.IO.StreamReader sr = new StreamReader(_FilePath + p_FileName + _FileExt,_FileEncoding);
 p_Content = sr.ReadToEnd();
 sr.Close();
 resultValue= true;
 }
 catch(Exception ex)
 {
 throw new Exception(ex.ToString());
 }

 return resultValue;
 }

 /// <summary>
 /// 保存文本文件
 /// </summary>
 /// <param name="p_FileName">文件名，不带路径，不带扩展名</param>
 /// <param name="p_Content">内容</param>
 /// <returns></returns>
 protected bool SaveFile(string p_FileName,string p_Content)
 {
 bool resultValue = false;
 try
 {
 System.IO.StreamWriter sw = new StreamWriter(_FilePath + p_FileName + _FileExt,false,_FileEncoding);
 sw.Write(p_Content);
 sw.Close();
 resultValue = true;
 }
 catch(Exception ex)
 {
 throw new Exception(ex.ToString());
 }

 return resultValue;

 }
 }
}

Cache.cs (Cache类)

using System;

namespace cacheweb.App_code.FileCache
{
 /// <summary>
 /// 文件Cache类
 /// Wathon Team.
 /// By Json Lee 2007-11-07
 /// http://www.wathon.com
 /// </summary>
 public class Caches:CacheBase
 {

 /// <summary>
 /// 保存Cache
 /// </summary>
 /// <param name="p_Content"></param>
 /// <param name="p_Url"></param>
 public void SetCache(string p_Content,string p_Url)
 {
 string fileNameNoExt = GetFileNameNoExt(p_Url);
 //写在这里
 this.SaveFile(fileNameNoExt,p_Content);
 }

 /// <summary>
 /// 检查Cache文件是否存在或过期
 /// </summary>
 /// <param name="p_Url"></param>
 /// <returns></returns>
 public bool ExistCache(string p_Url)
 {
 string fileNameNoExt = GetFileNameNoExt(p_Url);

 return this.ExistFile(fileNameNoExt);
 }

 /// <summary>
 /// 取Cache,请在使用之间先用 ExistCache 确定Cache存在
 /// </summary>
 /// <param name="p_Url"></param>
 /// <returns></returns>
 public string GetCache(string p_Url)
 {
 string strContent = "";
 string fileNameNoExt = GetFileNameNoExt(p_Url);
 this.ReadFile(fileNameNoExt,ref strContent);

 return strContent;
 }

 /// <summary>
 /// 根据域名取得无扩展名的文件名
 /// </summary>
 /// <param name="p_Url"></param>
 /// <returns></returns>
 private string GetFileNameNoExt(string p_Url)
 {
 string fileNameNoExt = p_Url.Replace("http://","");
 string fileExt = this.GetExtension(fileNameNoExt);
 fileNameNoExt = fileNameNoExt.Replace("/","_").Replace(fileExt,"");
 //处理未带文件名的情况
 if(fileNameNoExt == "")
 {
 fileNameNoExt = "default";
 }
 return fileNameNoExt;
 }

 /// <summary>
 /// 取扩展名
 /// </summary>
 /// <param name="fileName"></param>
 /// <returns></returns>
 private string GetExtension(string fileName)
 {
 try
 {
 int startPos = fileName.LastIndexOf(".");
 string ext = fileName.Substring(startPos, fileName.Length - startPos);
 return ext.ToLower();
 }
 catch (Exception ex)
 {
 //WrongLog.WriteErrorLog(ex.ToString());
 return string.Empty;
 }
 }

 /// <summary>
 /// 取有扩展名的文件名
 /// </summary>
 /// <param name="p_Url"></param>
 /// <returns></returns>
 protected string GetFileName(string p_Url)
 {
 try
 {
 int startPos = p_Url.LastIndexOf("/") + 1;
 string tmpFileName = p_Url.Substring(startPos, p_Url.Length - startPos);
 return tmpFileName;
 }
 catch (Exception ex)
 {
 //WrongLog.WriteErrorLog(ex.ToString());
 return string.Empty;
 }
 }

 }
}

posted on 2007-11-07 15:52 杨林阅读(372) 评论(0) 编辑收藏举报

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