net概述和改進(jìn)

1、ASP.NET 概述和改進(jìn)ADONET性能ASP.NET是一個(gè)統(tǒng)一的web 開(kāi)發(fā)模型，它包括您使用盡可能少的代碼生成企業(yè)級(jí)Web 應(yīng)用程序所必需的各種服務(wù)。ASP.NET 作為NET Framework 的一部分提供。當(dāng)您編寫(xiě)ASP.NET 應(yīng)用程序的代碼時(shí)，可以訪問(wèn)NET Framework 中的類。您可以使用與公共語(yǔ)言運(yùn)行庫(kù)（CLR ）兼容的任何語(yǔ)言來(lái)編寫(xiě)應(yīng)用程序的代碼，這些語(yǔ)言包括Microsoft visual Basic 、C#、JavaScript . NET 和J。使用這些語(yǔ)言，可以開(kāi)發(fā)利用公共語(yǔ)言運(yùn)行庫(kù)、類型安全、繼承等方面的優(yōu)點(diǎn)的ASP . NFT應(yīng)用程序。ASP.NET包括

2、：l 頁(yè)和控件樞架l ASP.NET 編譯器l 安全基礎(chǔ)結(jié)構(gòu)l 狀態(tài)管理功能l 應(yīng)用程序配置l 運(yùn)行狀況監(jiān)視和性能功能l 調(diào)試支持l XML Web services 框架l 可擴(kuò)展的宿主環(huán)境和應(yīng)用程序生命周期管理l 可擴(kuò)展的設(shè)計(jì)器環(huán)境ASP.NET 頁(yè)和控件樞架是一種編程框架，它在Web 服務(wù)器上運(yùn)行，可以動(dòng)態(tài)地生成和呈現(xiàn)ASP.NET 網(wǎng)頁(yè)。可以從任何瀏覽器或客戶端設(shè)備請(qǐng)求ASP.NET網(wǎng)頁(yè)，ASP.NET 會(huì)向請(qǐng)求瀏覽器呈現(xiàn)標(biāo)記（例如HTML ）。通常，您可以對(duì)多個(gè)瀏覽器使用相同的頁(yè)，因?yàn)锳SP.NET會(huì)為發(fā)出請(qǐng)求的瀏覽器呈現(xiàn)適當(dāng)?shù)臉?biāo)記。但是，您可以針對(duì)諸如Microsoft Inter

3、net Explorer 6 的特定瀏覽器設(shè)計(jì)ASP.NET 網(wǎng)頁(yè)，并利用該瀏覽器的功能。ASP.NET 支持基于Web 的設(shè)備（如移動(dòng)電話、手持型計(jì)算機(jī)和個(gè)人數(shù)字助理（PDA) ）的移動(dòng)控件。ASP.NET 網(wǎng)頁(yè)是完全面對(duì)對(duì)象的。在ASP.NET 網(wǎng)頁(yè)中，可以使用屬性、方法和事件來(lái)處理HTML 元素ASP.NET 頁(yè)框架為響應(yīng)在服務(wù)器上運(yùn)行的代碼中的客戶端事件提供統(tǒng)一的模型，從而使您不必考慮基于Web 的應(yīng)用程序中固有的客戶端和服務(wù)器隔離的實(shí)現(xiàn)細(xì)節(jié)。該框架還會(huì)在頁(yè)處理生命周期中自動(dòng)維護(hù)頁(yè)及該頁(yè)上控件的狀態(tài)。 使用ASP.NET 頁(yè)和控件框架還可以將常用的UI 功能封裝成易于使用且可重用的控件

4、?？丶恍杈帉?xiě)一次，即可用于許多頁(yè)并集成到ASP.NET 網(wǎng)頁(yè)中。這些控件在呈現(xiàn)期間放入ASP.NET 網(wǎng)頁(yè)中。 ASP.NET 頁(yè)和控件框架還提供各種功能，以便可以通過(guò)主題和外觀來(lái)控制網(wǎng)站的整體外觀和感覺(jué)。可以先定義主題和外觀，然后在頁(yè)面級(jí)或控件級(jí)應(yīng)用這些主題和外觀。 除了主題外，還可以定義母版頁(yè)，以使應(yīng)用程序中的頁(yè)具有一致的布局。一個(gè)母版頁(yè)可以定義您希望應(yīng)用程序中的所有頁(yè)（或一組頁(yè)）所具有的布局和標(biāo)準(zhǔn)行為。然后可以創(chuàng)建包含要顯示的頁(yè)特定內(nèi)容的各個(gè)內(nèi)容頁(yè)。當(dāng)用戶請(qǐng)求內(nèi)容頁(yè)時(shí)，這些內(nèi)容頁(yè)與母版頁(yè)合并，產(chǎn)生將母版頁(yè)的布局與內(nèi)容頁(yè)中的內(nèi)容組合在一起的輸出 所有ASP.KET 代碼都經(jīng)過(guò)了編譯，可提

5、供強(qiáng)類型、性能優(yōu)化和早期綁定以及其他優(yōu)點(diǎn)。代碼一經(jīng)編譯，公共語(yǔ)言運(yùn)行庫(kù)會(huì)進(jìn)一步將ASP.NET 編譯為本機(jī)代碼，從而提供增強(qiáng)的性能。 ASP.NET 包括一個(gè)編譯器，該編譯器將包括頁(yè)和控件在內(nèi)的所有應(yīng)用程序組件編譯成一個(gè)程序集，之后ASP.NET 宿主環(huán)境可以使用該程序集來(lái)處理用戶請(qǐng)求。 除了. NET 的安全功能外，ASP.NET 還提供了高級(jí)的安全基礎(chǔ)結(jié)構(gòu)，以便對(duì)用戶進(jìn)行身份驗(yàn)證和授權(quán)，并執(zhí)行其他與安全相關(guān)的功能。您可以使用由IIS 提供的Windows 身份驗(yàn)證對(duì)用戶進(jìn)行身份驗(yàn)證，也可以通過(guò)您白己的用戶數(shù)據(jù)使用ASP.NET Forms身份驗(yàn)證和ASP.NET成員資格來(lái)管理身份驗(yàn)證。此外

6、，可以使用Windows 組或您自己的自定義角色數(shù)據(jù)庫(kù)（使用ASPNET 角色）來(lái)管理Web 應(yīng)用程序的功能和信息方面的授權(quán)。您可以根據(jù)應(yīng)用程序的需要方便地移除、添加或并換這些方案。 ASP.NET 始終使用特定的Windows 標(biāo)識(shí)運(yùn)行，因此您可以通過(guò)使用w indows 功能（例如NTFS 訪問(wèn)控制列表（ACL ）、數(shù)據(jù)庫(kù)權(quán)限等等）來(lái)保護(hù)應(yīng)川、用程序的安全。 ASP. NET 提供了內(nèi)部狀態(tài)管理功能，它使您能夠存儲(chǔ)頁(yè)請(qǐng)求期間的信息，例如客戶信息或購(gòu)物車的內(nèi)容。您可以保存和管理應(yīng)用程序特定、會(huì)話特定、頁(yè)特定、用戶特定和開(kāi)發(fā)人員定義的信息。此信息可以獨(dú)立于頁(yè)上的任何控件。ASP.NET 提供了

7、分布式狀態(tài)功能，使您能夠管理一臺(tái)計(jì)算機(jī)或數(shù)臺(tái)計(jì)算機(jī)上同一應(yīng)用程序的多個(gè)實(shí)例的狀態(tài)信息。 通過(guò)ASP.NET 應(yīng)用程序使用的配置系統(tǒng)，可以定義Web 服務(wù)器、網(wǎng)站或單個(gè)應(yīng)用程序的配置設(shè)置。您可以在部署ASP.NET 應(yīng)用程序時(shí)定義配置設(shè)置，并且可以隨時(shí)添加或修訂配置設(shè)置，且對(duì)運(yùn)行的Web 應(yīng)用程序和服務(wù)器具有最小的影響。ASP.NET 配置設(shè)置存儲(chǔ)在基于XML 的文件中。由于這些XML 文件是ASCII 文本文件，因此對(duì)Web 應(yīng)用程序進(jìn)行配置更改比較簡(jiǎn)單。您可以擴(kuò)展配置方案，使其符合自己的要求。 ASP.NET 包括可監(jiān)視ASP.NET 應(yīng)用程序的運(yùn)行狀況和性能的功能。使用ASP . NFT

8、運(yùn)行狀況監(jiān)視可以報(bào)告關(guān)鍵事件，這些關(guān)鍵事件提供有關(guān)應(yīng)用程序的運(yùn)行狀況和錯(cuò)誤情況的信息。這些事件顯示診斷和監(jiān)視特征的組合，并在記錄哪些事件以及如何記錄事件等方面提供了高度的靈活性。ASP.NET 支持兩組可供應(yīng)用程序訪問(wèn)的性能計(jì)數(shù)器： ASP.NET 系統(tǒng)性能計(jì)數(shù)器組 ASP.NET 應(yīng)程序性能計(jì)數(shù)器組ASP.NET 利用運(yùn)行庫(kù)調(diào)試基礎(chǔ)結(jié)構(gòu)來(lái)提供跨語(yǔ)言和跨計(jì)算機(jī)調(diào)試支持?？梢哉{(diào)試托管和非托管對(duì)象，以及公共語(yǔ)言運(yùn)行庫(kù)和腳本語(yǔ)言支持的所有語(yǔ)言。這章提供證明策略幫助你設(shè)計(jì)并且發(fā)展可調(diào)節(jié)的數(shù)據(jù)存取解決辦法。本文包括不同的技術(shù)來(lái)通過(guò)數(shù)據(jù)遍布應(yīng)用層，管理數(shù)據(jù)庫(kù)連接工具，優(yōu)化儲(chǔ)存的過(guò)程調(diào)用，降低數(shù)據(jù)集的大量銷

9、費(fèi)，通過(guò)大量結(jié)果數(shù)據(jù)集標(biāo)識(shí)的技術(shù)，管理傳送，操作BLOBS 等。目標(biāo)優(yōu)化數(shù)據(jù)存取設(shè)計(jì)在Data Sets 和Data Readers 之間做出選擇運(yùn)行有效的數(shù)據(jù)庫(kù)命令有效地在層之間流通數(shù)據(jù)進(jìn)行有效的交易優(yōu)化連接管理評(píng)估記錄標(biāo)識(shí)費(fèi)用評(píng)估分析數(shù)據(jù)存取性能標(biāo)準(zhǔn)BLOB 操作方案的執(zhí)行性能概述精心設(shè)計(jì)的數(shù)據(jù)訪問(wèn)代碼和數(shù)據(jù)處理命令是應(yīng)用性能和可伸縮性的根本要素。通常，數(shù)據(jù)庫(kù)是一個(gè)由大量應(yīng)用請(qǐng)求需要來(lái)自數(shù)據(jù)庫(kù)的數(shù)據(jù)導(dǎo)致的應(yīng)用負(fù)載的焦點(diǎn)。這章為設(shè)計(jì)和實(shí)施數(shù)據(jù)訪問(wèn)代碼的性能及可伸縮性提供證明策略。如何使用使用這章可以改進(jìn)數(shù)據(jù)訪問(wèn)代碼性能及伸縮性的實(shí)施為了最有效地使用這章，考慮如下內(nèi)容： · 只讀標(biāo)題

10、或者從開(kāi)始讀到結(jié)束。這章主要標(biāo)題幫助你迅速鑒定然后找到使你感興趣的題目?；蛘撸憧梢詮念^到尾地讀獲得完整的影響ADO. NET 性能問(wèn)題那一章。 · 使用檢查表。使用“檢查表：ADO.NET 性能”迅速在”檢查表”部分看到和評(píng)估人在這兒章內(nèi)提出的那些指南。 · 使用這章的“結(jié)構(gòu)”部分理解ADO.NET 怎樣工作。通過(guò)理解結(jié)構(gòu)，你能更好地設(shè)計(jì)和實(shí)施選擇。理解ADO.NET核心組成部分，例如數(shù)據(jù)支持對(duì)象和數(shù)據(jù)集對(duì)象。 · 使用“設(shè)計(jì)方案”來(lái)理解那些將影響ADONET代碼選擇的實(shí)施的高級(jí)決定 · 度量應(yīng)用性能。了解你所能使用度量應(yīng)用性能的關(guān)鍵計(jì)量學(xué)。你必須度量

11、應(yīng)用性能，以便你能鑒定并且解決執(zhí)行問(wèn)題。 · 測(cè)試你的應(yīng)用性能?！皽y(cè)試.NET 應(yīng)用性能”獲悉怎樣把性能試驗(yàn)應(yīng)用于你的應(yīng)用程序。你必須使用一個(gè)前后一致的測(cè)試過(guò)程并且分析結(jié)果。 · 調(diào)試應(yīng)用性能。通過(guò)“協(xié)調(diào)NET 應(yīng)用性能”來(lái)了解怎樣通過(guò)使用協(xié)調(diào)計(jì)量學(xué)鑒定解決性能問(wèn)題。 · 調(diào)試SQLServer 。讀第14 章“提高SQL 性能”，確保你的Mi crosoft®SQL Server 數(shù)據(jù)庫(kù)格式正確。結(jié)構(gòu)性 ADO . NET 依賴數(shù)據(jù)支持提供進(jìn)入基礎(chǔ)數(shù)據(jù)源的途徑。每個(gè)數(shù)據(jù)支持顯示你所使用的管理連接，恢復(fù)數(shù)據(jù)，更新數(shù)據(jù)。核心對(duì)象是如下內(nèi)容：· 連

12、接· 命令· 數(shù)據(jù)讀取器· 數(shù)據(jù)適配器 另外，ADO . NET 提供DataSet 對(duì)象，來(lái)提供分離的高速數(shù)據(jù)緩存。DataSet 對(duì)象不需要一種數(shù)據(jù)源的具體的類型并且不被所獲得的基礎(chǔ)數(shù)據(jù)源數(shù)據(jù)所束縛。基本的ADO . NET 結(jié)構(gòu)如圖12 . 1 所示。 圖12.1 ADO.NET 結(jié)構(gòu)圖 下列目錄略述每個(gè)主要ADO.NET 物體的對(duì)象：· 連接。這個(gè)對(duì)象描述對(duì)數(shù)據(jù)庫(kù)的一個(gè)連接· 命令。這個(gè)對(duì)象代表當(dāng)連接一個(gè)數(shù)據(jù)源時(shí)被運(yùn)行的一個(gè)SQL 語(yǔ)句。這個(gè)對(duì)象可能是一個(gè)儲(chǔ)存的程序或者一個(gè)直接的SQL 語(yǔ)句。· 數(shù)據(jù)讀取器。這個(gè)對(duì)象用來(lái)恢復(fù)一

13、條來(lái)自數(shù)據(jù)庫(kù)的數(shù)據(jù)的只讀數(shù)據(jù)流。與以功能性作為代價(jià)將數(shù)據(jù)讀進(jìn)一個(gè)DataSet對(duì)象相比較，DataReader 對(duì)象是為連接腳本設(shè)計(jì)的并且能提供更好的性能。· 數(shù)據(jù)適配器。來(lái)自一個(gè)Data Set 對(duì)象和基礎(chǔ)的數(shù)據(jù)源的對(duì)象信道數(shù)據(jù)。數(shù)據(jù)適配器對(duì)象也提供以前與Record set 對(duì)象相關(guān)的改進(jìn)的批處理特征。· 數(shù)據(jù)集。數(shù)據(jù)集對(duì)象描述一個(gè)分離的，隱藏的數(shù)據(jù)集。數(shù)據(jù)集不依賴提供者并不被可能依附于它的基礎(chǔ)的數(shù)據(jù)源所束縛。數(shù)據(jù)集能容易地從部件到部件通過(guò)各種各樣層來(lái)應(yīng)用，并且它可以被作為XML 連載。 你應(yīng)該了解數(shù)據(jù)集內(nèi)部建造的方式，因?yàn)閿?shù)據(jù)集包含一個(gè)潛在的大量的內(nèi)部對(duì)象。這表明許多

14、存儲(chǔ)分配程序被要求建造典型的數(shù)據(jù)集。 數(shù)據(jù)集由一個(gè)或更多數(shù)據(jù)表對(duì)象以及數(shù)據(jù)關(guān)剔象組成。每個(gè)數(shù)據(jù)表包含數(shù)據(jù)行w 對(duì)象和數(shù)據(jù)列對(duì)象。限制對(duì)象用來(lái)代表可以被在一個(gè)或更多數(shù)據(jù)列對(duì)象上實(shí)施的限制條件。注意 你也能使用從基本數(shù)據(jù)集派生來(lái)的典型數(shù)據(jù)集。典型數(shù)據(jù)集優(yōu)越性在于構(gòu)造時(shí)間和運(yùn)行時(shí)間。· 數(shù)據(jù)視圖。數(shù)據(jù)視圖對(duì)象雖然不在12.1 圖顯示，但是你能使用一個(gè)數(shù)據(jù)視圖使數(shù)據(jù)在數(shù)據(jù)表內(nèi)存儲(chǔ)和分類。這種性能經(jīng)常用于具有約束力的數(shù)據(jù)。ASP.NET Overview and Improving ADO . NET PerformanceASP.NET is a unified Web developmen

15、t model that includes the services necessary for you to build enterprise-class Web applications with a minimum of coding . ASP.NET is part of the . NET Framework , and when coding ASP.NET applications you have access to classes in the . NET Framework . You can code your applications in any Language

16、compatible with the common language runtime ( CLR ) , including Microsoft Visual Basic , C # , . NET , and J # . These languages enable you to develop ASP. NET applications that benefit from the common language runtime , type safely , inheritance , and so on . ASP.NET Includes :l A page and controls

17、 framework l The ASP.NET compiler l Security infrastructure l State-management facilities l Application configuration l Health monitoring and performance features l Debugging support l An XML Web services framework l Extensible hosting environment and application life cycle management l An extensibl

18、e designer environment The ASP.NET page and controls framework is a Programming framework that runs on a Web server to dynamically produce and render , ASP.NET Web pages . ASP.NET Web pages can be requested form any browser or client device , and ASP.NET renders markup ( such as HTML ) to the reques

19、ting browser , As a rule , you can use the same page for multiple browsers , because ASP.NET renders the appropriate markup for the browser making the request . However , you can design your ASP.NET Web page to target a specific browser , such as Microsoft Internet Explorer 6 , and take advantage of

20、 the features of that browser . ASP.NET supports mobile controls for Web-enabled devices such as phones , handheld computers , and personal digital assistants ( PDAS ) . ASP.NET Web pages are completely object-oriented . Within ASP.NET Web pages you can work with HTML elements using properties , met

21、hods , and events . The ASP.NET page framework removes the implementation details of the separation of client and server inherent in Web -based applications by presenting a unified model for responding to client events in code that runs at the server . The framework also。automatically maintains the

22、state of apage and the controls on that Page during the page processing life cycle . The ASP.NET page and controls framework also enables you to encapsulate common UI functionality in easy-to-use , reusable controls . Controls are written once , can be used in many pages , and are integrated into th

23、e ASP.NET Web page that they are placed in during rendering . The ASP.NET page and controls framework also provides features to control the overall look and feel of your Web site via themes and skins . You can define themes and skins and then apply them at a page level or at a control level . In add

24、ition to themes , you can define master pages that you use to create a consistent layout for the pages in your application . A single master page defines the layout and standard behavior that you want for all the pages ( or a group of pages ) in your application . You can then create individual cont

25、ent pages that contain the page-specific content you want to display . When users request the content pages . they merge with the master page to Produce output that combines the layout of the master page with the content from the content page . All ASP.NET code is compile , which enables strong typi

26、ng , performance optimizations , and early binding . among other benefits . once the code has been compiled , the common language runtime further compiles ASP.NET code to native code , Providing improved performance . ASP.NET includes a compiler that will compile all your application components incl

27、uding pages and controls into an assembly that the ASP.NET hosting environment can then use to service user requests , In addition to the security features of . NET , ASP.NET provides an advanced security infrastructure for authenticating and authorizing user access as well as performing other secur

28、ity-related tasks .You can authenticate users using Windows authentication supplied by IIS . or you can manage authentication using your own user database using ASP.NET forms authentication and ASP.NET membership . Additionally , you can manage the authorization to the capabilities and information o

29、f your Web application using Windows groups or your own custom role database using ASP.NET roles . You can easily remove . add to , or replace these schemes depending upon the needs of your application . ASP.NET always runs with a particular Windows identity so you can secure your application using

30、Windows capabilities such as NTFS Access Control Lists ( ACLS ) , database permissions , and so on , For more information on the identity of ASP.NET , ASP.NET provides intrinsic state management , functionality that enables you to store information between page requests , such as customer informatio

31、n or the contents of a shopping cart . You can save and manage application-specific , session-specific , page-specific , user-specific , and developer-defined information . This information can be independent of any controls on the page . ASP.NET offers distributed state facilities ,which enable you

32、 to manage state information across multiple instances of the same application on one computer or on several computers . ASP.NET applications use a configuration system that enables you to define configuration settings for your Web server , for a Web site , or for individual applications . You can m

33、ake configuration settings at the time your ASP.NET applications are deployed and can add or revise configuration settings al any time with minimal impact on operational Web applications and servers . ASP.NET configuration settings are stored in XML-based fies . Because these XML files are ASCII tex

34、t files , it is simple to make configuration changes to your Web applications . You can extend the configuration scheme to suit your requirements . ASP.NET includes features that enable you to monitor health and performance of your ASP.NET application . ASP.NET health monitoring enables reporting of

35、 key events that provide information about the health of an application and about error conditions , These events show a combination of diagnostics and monitoring characteristics and offer a high degree of flexibility in terms of what is logged and how it is logged . ASP.NET supports two groups of p

36、erformance counters accessible to your applications : The ASP.NET system performance counter group The ASP.NET application performance counter group ASP.NET takes advantage of the run-time debugging infrastructure to provide cross-language and cross-computer debugging support . You can debug both ma

37、naged and unmanaged objects , as well as all languages supported by the common language runtime and script languages .This chapter provides proven strategies to help you design and develop scalable data access solutions . Topics covered include different techniques to pass data across application la

38、yers , managing the database connection pool, optimizing stored procedure calls , reducing dataset serialization cost , techniques for paging through large result sets , managing transactions , handling BLOBS , and much more .ObjectivesOptimize your data access design . Choose between Datasets and D

39、ata Readers . Run efficient database commands . Pass data between layers efficiently Perform efficient transactions . Optimize connection management . Evaluate the cost of paging through records . Evaluate criterion for analyzing data access performance . Apply Performance considerations to binary l

40、arge object ( BLOB ) . Overview Well-designed data access code and data processing commands are essential elements for application performance and scalability，Typically the database is a focal point for application load because the majority of application requests require data that comes from a data

41、base. This chapter provides proven strategies for designing and implementing data access code for performance and scalability How to Use This Chapter Use this chapter to improve the implementation of your data access code for performance and scalability. To get the most out of this chapter , conside

42、r the following : Jump to topics or read beginning to end . The main headings in this chapter help you to quickly identify and then locate the topic that interests you . Alternatively , you can read the chapter beginning to end to gain a thorough appreciation of the issues that affect ADO.NET perfor

43、mance . Use te checklist . Use " Checklist : ADO.NET Performance " in the " Checklist " section of this guide to quickly view and evaluate the guideline presented in this chapter. Use the " Architecture" section of this chapter to understand how ADO.NET worksBy understa

44、nding the architecture , you can make better design and implementation choices . Understand core ADO.NET components，such as data provider objects and the Dataset object . Use the " Design Considerations" section of this chapter to understand the high-level decisions that will affect implem

45、entation choices for ADO. NET Code. Measure your application performance . learn about the key metrics that you can use to measure application performance You have to measure application performance so that you can identify and resolve performance issues . Test your application performance .Testing

46、.NET Application Performanceto learn how to apply performance testing to your application . You have to apply a coherent testing process and analyze the results .Tune your application Performance. Tuning .NET Application Performanceto learn how to resolve performance issues that you identify through

47、 the use of tuning metrics . Tune SQL Server.Reed Chapter 14 , " improving SQL Server Performance to ensure that your Microsoft® SQL server database is appropriately configured.ArchitectureADO.NET relies on data providers to provide access to the underlying data source . Each data provider

48、 exposes a set of objects that you use to manage connections , retrieve data , and update data.The core objects are the following : Connection Command Data Reader Data Adapter In addition , ADO.NET provides the Dataset object , which provides a disconnected cache of data .the Dataset object does not

49、 require a specific type of data source and is not tied to the underlying data source that the data was obtained from. The basic AD0.NET architecture is shown in Figure l2.l.Figure 12.1：ADO.NET architectureThe following list outlines the purpose of each of the main AD0. NET objects: Connection . This object represents a connection to a database . Command . This object represents an SQL statement that is run while connected to a data source . This object can be a stored procedure or a direct SQL statement Data Reader. This object retrieves a read-only , forward-only stream of data from