在开发中编写的js、css发布的时候，往往需要进行压缩，以减少文件大小，减轻服务器的负担。这就得每次发版本的时候，对js、js进行压缩，然后再发布。有没有什么办法，让代码到了服务器上边，它自己进行压缩呢？
有两种办法：
第一种，在css、js请求到来的时候读取一下相对应的文件，进行压缩后返回。此方法可以通过在Global.asax的Application_BeginRequest的事件中，进行处理，也可以在web.config中注册一个httpHandler进行处理。
第二种是在程序启动的时候，对全部css以及js进行压缩，压缩之后，每次访问都使用压缩后的文件即可。这种办法可以将js全部压缩到一个文件夹里边，不过需要注意一下文件的顺序。
压缩使用的是雅虎的压缩组件: Yahoo.Yui.Compressor.dll
由于第一种办法没能实现js压缩到一个文件，所以这里采用的是第二种方案。
压缩方法比较简单，首先引用Yahoo.Yui.Compressor.dll和EcmaScript.NET.modified.dll
压缩js
//文件内容
string strContent = File.ReadAllText(jsPath, Encoding.UTF8);
//初始化
var js = new JavaScriptCompressor(strContent, false, Encoding.UTF8, System.Globalization.CultureInfo.CurrentCulture);
//压缩该js
strContent = js.Compress();
File.WriteAllText(jsPath, strContent, Encoding.UTF8);
压缩css
string strContent = File.ReadAllText(cssPath, Encoding.UTF8)
//进行压缩
strContent = CssCompressor.Compress
(strContent);
File.WriteAllText(cssPath, strContent, Encoding.UTF8);
还有另外一一种办法不用自己写代码，每次网站发布的时候自动压缩指定的js和css文件：
1）在项目中新建“MSBuild” 文件夹，把yahoo压缩组件的两个dll放进去
2）在“文件夹”内新建”MSBuildCompressor.xml”文件:
<?xml version=”1.0″ encoding=”utf-8″ ?>
<Project xmlns=”http://schemas.microsoft.com/developer/MsBuild/2003″>
<UsingTask
TaskName=”CompressorTask”
AssemblyFile=”Yahoo.Yui.Compressor.dll” />
<!– The .NET 2.0 version of the task .. and yes .. that’s Model.Net20 folder listed twice .. i know i know…
<UsingTask
TaskName=”CompressorTask”
AssemblyFile=”..\..\Projects\Yahoo.Yui.Compressor\Model.Net20\Model.Net20\bin\Debug\Yahoo.Yui.Compressor.NET20.dll” />
–>
<!– Define the output locations. These can be set via the msbuild command line using
/p:CssOutputFile=$(TargetDir)../whatever…
/p:JavaScriptOutputFile=$(TargetDir)../whatever…
If they are not supplied or are empty, then we the value whatever is supplied, below.
–>
<PropertyGroup>
<CssOutputFile Condition=” ‘$(CssOutputFile)’==” “>
SylesSheetFinal.css
</CssOutputFile>
<JavaScriptOutputFile Condition=” ‘$(JavaScriptOutputFile)’==” “>
JavaScriptFinal.css
</JavaScriptOutputFile>
</PropertyGroup>
<Target Name=”MyTaskTarget”>
<!–
ItemGroup\CssFiles or ItemGroup\JavaScriptFiles: add zero to many files you wish to include in this compression task.
Don’t forget, you can use the wildcard (eg. *.css, *.js) if you feel up to it.
Finally, at least one item is required – either a css file or a js file.
CssFiles/JavaScriptFiles data format: Please do not touch this.
DeleteCssFiles: [Optional] True | Yes | Yeah | Yep | True | FoSho | FoSho. Default is False. Anything else is False. (eg. blah = false, xxxx111 = false, etc)
CssCompressionType: YuiStockCompression | MichaelAshsRegexEnhancements | HaveMyCakeAndEatIt or BestOfBothWorlds or Hybrid; Default is YuiStockCompression.
ObfuscateJavaScript: [Optional] refer to DeleteCssFiles, above.
PreserveAllSemicolons: [Optional] refer to DeleteCssFiles, above.
DisableOptimizations: [Optional] refer to DeleteCssFiles, above.
EncodingType: [Optional] ASCII, BigEndianUnicode, Unicode, UTF32, UTF7, UTF8, Default. Default is ‘Default’.
DeleteJavaScriptFiles: [Optional] refer to DeleteCssFiles, above.
LineBreakPosition: [Optional] the position where a line feed is appened when the next semicolon is reached. Default is -1 (never add a line break).
0 (zero) means add a line break after every semicolon. (This might help with debugging troublesome files).
LoggingType: None | ALittleBit | HardcoreBringItOn; Hardcore also lists javascript verbose warnings, if there are any (and there usually is 😛 ).
ThreadCulture: [Optional] the culture you want the thread to run under. Default is ‘en-gb’.
IsEvalIgnored: [Optional] compress any functions that contain ‘eval’. Default is False, which means a function that contains
‘eval’ will NOT be compressed. It’s deemed risky to compress a function containing ‘eval’. That said,
if the usages are deemed safe this check can be disabled by setting this value to True.
–>
<ItemGroup>
<!– Single files, listed in order of dependency
<CssFiles Include=”../StylesheetSample1.css”/>
<CssFiles Include=”../StylesheetSample2.css”/>
<CssFiles Include=”../StylesheetSample3.css”/>
<CssFiles Include=”../StylesheetSample4.css”/>–>
<JavaScriptFiles Include=”../myjs/sample_1.js”/>
<!– All the files. They will be handled (I assume) in alphabetically. –>
<!–<CssFiles Include=”*.css” />
<JavaScriptFiles Include=”*.js” />
–>
</ItemGroup>
<CompressorTask
CssFiles=”@(CssFiles)”
DeleteCssFiles=”false”
CssOutputFile=”$(CssOutputFile)”
CssCompressionType=”YuiStockCompression”
JavaScriptFiles=”@(JavaScriptFiles)”
ObfuscateJavaScript=”False”
PreserveAllSemicolons=”False”
DisableOptimizations=”Nope”
EncodingType=”utf-8″
DeleteJavaScriptFiles=”false”
LineBreakPosition=”-1″
JavaScriptOutputFile=”$(JavaScriptOutputFile)”
LoggingType=”ALittleBit”
ThreadCulture=”en-au”
IsEvalIgnored=”false”
/>
<!–
CssFiles=”@(CssFiles)”
DeleteCssFiles=”false”
CssOutputFile=”$(CssOutputFile)”
CssCompressionType=”YuiStockCompression”
JavaScriptFiles=”@(JavaScriptFiles)”
ObfuscateJavaScript=”False” //是否模糊处理js文件，True：会将js中的变量为“a,b,c”单个字符的变量
PreserveAllSemicolons=”False”
DisableOptimizations=”Nope”
EncodingType=”utf-8″ //如果js或者css包含有中文，则必须使用utf-8编码，否则会乱码
DeleteJavaScriptFiles=”false”
LineBreakPosition=”-1″
JavaScriptOutputFile=”$(JavaScriptOutputFile)”
LoggingType=”ALittleBit”
ThreadCulture=”en-au”
IsEvalIgnored=”false”
–>
</Target>
</Project>
3）选择网站属性，切换到“生成事件”标签，，在“”输入以下命令：
$(MSBuildBinPath)\msbuild.exe “$(ProjectDir)MSBuild\MSBuildCompressor.xml” /p:CssOutputFile=”../miniFile/Sieena.min.css” /p:JavaScriptOutputFile=”../miniFile/Sieena.min.js”
这样，每次编译网站的时候就会自动压缩指定的js和css文件了
官方地址：
转自：http://www.cnblogs.com/timy/archive/2011/10/30/2229640.html
