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The author:(作者)delvpublished in(发表于) 2014/1/8 7:04:14 小议优化ASP.NET应用性能之ViewState篇_[Asp.Net教程]
Machine级 在machine.config中设置 Application级 在Web Applicatin的web.config中设置 单页面级 在该页面中设置<%@Page enableViewStateMac='false' %>或通过代码设置Page.EnableViewStateMac = false; 可是,如果我们完全能通过禁用ViewState来解决数据传输负担而且不产生副作用的话,那MS的架构师们也不会傻到如此可爱的地步(可有可无的东东留它何用?),正因我们往往不能通过简单的禁用来解决这个传输负担问题,所以我们只能另辟路径使之在网络往返中传输量尽可能地小,于是,压缩成了我们的首选。只要我们重载Page类的SavePageStateToPersistenceMedium()方法与LoadPageStateFromPersistenceMedium()方法,并在重载方法中对数据进行压缩与解压的处理即可。开源项目SharpZipLib提供的类GZipInputStream与GZipOutputStream进入了我们的视野,为了方便,不妨写个类CompressionHelper,代码如下:
1using System.IO; 2using ICSharpCode.SharpZipLib.GZip; 3 4namespace Ycweb.Components 5{ 6 /**//// 7 /// Summary description for CompressionHelper. 8 /// 9 public class CompressionHelper10 {11 public CompressionHelper()12 {13 //14 // TOD Add constructor logic here15 //16 }1718 /**//// 19 /// 压缩数据20 /// 21 /// 待压缩的字节数组22 /// 压缩后的字节数组23 public static byte[] CompressByte(byte[] data)24 {25 MemoryStream ms = new MemoryStream();26 Stream s=new GZipOutputStream(ms); 27 s.Write( data, 0, data.Length );28 s.Close();29 return ms.ToArray(); 30 }3132 /**//// 33 /// 解压数据34 /// 35 /// 待解压的字节数组36 /// 解压出的字节数组37 public static byte[] DeCompressByte(byte[] data)38 {39 byte[] writeData = new byte[2048];40 MemoryStream ms= new MemoryStream( data );41 Stream sm = new GZipInputStream(ms) as Stream;42 MemoryStream outStream = new MemoryStream();43 while (true)44 {45 int size = sm.Read(writeData,0, writeData.Length );46 if (size >0)47 {48 outStream.Write(writeData,0,size);49 }50 else51 {52 break;53 }54 }55 sm.Close();56 byte[] outArr = outStream.ToArray();57 outStream.Close();58 return outArr; 59 }60 }61}
然后我们在派生于类Page的页面控制基类中重载方法LoadPageStateFromPersistenceMedium()与SavePageStateToPersistenceMedium(Object viewState),代码如下:
1Load & Save ViewState Data#region Load & Save ViewState Data 2 protected override object LoadPageStateFromPersistenceMedium() 3 { 4//从自己注册的隐藏域__SmartViewState中读取数据 5 string viewState = Request.Form["__SmartViewState"]; 6 byte[] bytes = Convert.FromBase64String(viewState); 7 //调用上面提供的静态方法CompressionHelper.DeCompressByte()来解压数据 8 bytes = CompressionHelper.DeCompressByte(bytes); 9 LosFormatter formatter = new LosFormatter();10 return formatter.Deserialize(Convert.ToBase64String(bytes));11 12 }1314 protected override void SavePageStateToPersistenceMedium(Object viewState)15 {16 LosFormatter formatter = new LosFormatter();17 StringWriter writer = new StringWriter();18 formatter.Serialize(writer, viewState);19 string viewStateString = writer.ToString();20 byte[] bytes = Convert.FromBase64String(viewStateString);21 //调用上面提供的静态方法CompressionHelper.CompressByte()来压缩数据22 bytes = CompressionHelper.CompressByte(bytes);23 24 //注册一个新的隐藏域__SmartViewState,你也可以自己定义25 this.RegisterHiddenField("__SmartViewState", Convert.ToBase64String(bytes)); 26 }27#endregion
经过以上处理,web输出页面中的源代码就是型如:
原来的隐藏域"__VIEWSTATE"值为空,而取而代之的是我们自己注册的新的隐藏域"__SmartViewState"来存储了经过压缩后的字符串,这样以来,提速效果是明显的,结合我们的项目,象DG3G.COM的首页原ViewState串值大约是28K,压缩后为7K,而Acafa.com的首页原ViewState串值大约是43K,压缩后为8K。这样的处理还是比较令人满意的。当然,如果你觉得还不够彻底,你还可以把ViewState串存储在Session中,不过这样做,对服务器内存的压力将陡增(尤其是访问量较大的时候),建议还是不要轻易使用,如果你Web服务器内存有个10G、8G的,不妨试试。下面给出相关修改代码:
将上述LoadPageStateFromPersistenceMedium()方法体中的代码: string viewState = Request.Form["__SmartViewState"];修改为: string viewState = Session["__SmartViewState"].ToString();同时,将上述SavePageStateToPersistenceMedium()体中的代码: this.RegisterHiddenField("__SmartViewState", Convert.ToBase64String(bytes));修改为: Session["__SmartViewState"] = Convert.ToBase64String(bytes);
末了,以上代码和方案均来自VS2003开发实践,对VS2005是否合适,本人不做任何承诺,不过如果你能从以上方案中有所收获,我将感到无比的高兴。
来源:网络
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