外文翻譯-構(gòu)建豐富互聯(lián)網(wǎng)應(yīng)用程序的新方法

1、1外文資料翻譯譯文構(gòu)建豐富互聯(lián)網(wǎng)應(yīng)用程序的新方法豐富的互聯(lián)網(wǎng)應(yīng)用程序有桌面軟件在線(xiàn)運(yùn)行的特征和功能，這種應(yīng)用止越來(lái) 越重要和流行。ria的功能響應(yīng)的用戶(hù)界面和交互能力。這使得以因特網(wǎng)為基礎(chǔ) 的程序更易于使用和更多的功能，并且述克服了傳統(tǒng)的web應(yīng)用問(wèn)題，如性能 降低和有限間活動(dòng)的問(wèn)題。但是，這些程序比傳統(tǒng)的應(yīng)用程序開(kāi)發(fā)棘手，ria開(kāi)發(fā)平臺(tái)型廠(chǎng)商laszlo系統(tǒng) 公司的首席技術(shù)官大衛(wèi)特姆金標(biāo)注。例如，網(wǎng)絡(luò)是無(wú)狀態(tài)的。網(wǎng)絡(luò)，web服務(wù) 器，而不是客戶(hù)端，通?？梢怨?jié)省交易的狀態(tài)。當(dāng)服務(wù)器必須為每一個(gè)ria用 戶(hù)維持會(huì)話(huà)可能會(huì)出現(xiàn)縮放問(wèn)題,burton集團(tuán)的市場(chǎng)研究公司的分析師柯克克內(nèi) 恩席爾德說(shuō)。到

2、2005年,開(kāi)發(fā)者們正在學(xué)習(xí)，如何使用ajax （異步j(luò)avascript和xml） 來(lái)創(chuàng)建應(yīng)用程序，如谷歌地圖類(lèi)似桌面的界面。他們隨后用它來(lái)創(chuàng)建整個(gè)企業(yè)的 ria。一些廠(chǎng)商最近發(fā)布了自己的基于ajax的ria開(kāi)發(fā)平臺(tái)，包括微軟的asp.net ajax和谷歌網(wǎng)頁(yè)工具包。其他公司也未發(fā)布基于ajax的ria平臺(tái)，包括adobe systems 的 flash 和 air（ adobe 集成運(yùn)行），微軟的 silverlight 和 sun microsystems 的 javafxo這些方法已經(jīng)在ajax功能擴(kuò)展，使企業(yè)使用ajax使自己的應(yīng)用程序開(kāi)發(fā)產(chǎn) 品更有吸引力，或讓供應(yīng)商給ria開(kāi)發(fā)自

3、己的自旋。豐富的互聯(lián)網(wǎng)應(yīng)用ria的通常具有客戶(hù)端處理的用戶(hù)界面相關(guān)的活動(dòng)，而應(yīng)用服務(wù)器進(jìn)程并存 儲(chǔ)數(shù)據(jù)，并簡(jiǎn)化了向客戶(hù)端發(fā)送數(shù)據(jù)更新。這將釋放服務(wù)器資源，從而使同樣的 碩件可以同時(shí)處理更多的客戶(hù)端會(huì)話(huà)。它還減少客戶(hù)端服務(wù)器通信，從而帶 來(lái)更好的性能。一個(gè)ria通常，但不總是，在瀏覽器內(nèi)運(yùn)行，并且不要求在客戶(hù)機(jī)上的軟件 安裝。出于安全考慮，大多數(shù)的ria在沙箱中運(yùn)行他們的客戶(hù)元素。ria的典 型特征是異步通信，其中客戶(hù)端引擎無(wú)需等待用戶(hù)來(lái)執(zhí)行操作，如點(diǎn)擊鏈接與服 務(wù)器進(jìn)行交互。這增加了響應(yīng)性，因?yàn)橛脩?hù)不必等待數(shù)據(jù)客戶(hù)端和服務(wù)器之間移 動(dòng)。例如，用戶(hù)可以操縱一個(gè)谷歌地圖顯示而不等待頁(yè)面每次重裝。a

4、jax在adaptive path的產(chǎn)品設(shè)計(jì)顧問(wèn)公司的總裁杰西詹姆斯加勒特，杜撰的縮寫(xiě) ajax在2005年。但是，實(shí)際上公司幾年前就開(kāi)始與技術(shù)相關(guān)的工作。ajax應(yīng)用程序通常創(chuàng)建瀏覽器引擎中運(yùn)行基于javascript的代碼。發(fā)動(dòng)機(jī)截 取用戶(hù)輸入，請(qǐng)求料顯示器，并處理在客戶(hù)端交互。如果發(fā)動(dòng)機(jī)需要更多的數(shù)據(jù), 它請(qǐng)求從在后臺(tái)服務(wù)器材料，讓用戶(hù)繼續(xù)與程序進(jìn)行交互。該方法利用異步j(luò)avascript中，其中的html頁(yè)可使用來(lái)?yè)艽螂娫?huà)到web 服務(wù)器抓取的文檔。這讓?xiě)?yīng)用程序進(jìn)行調(diào)用服務(wù)器，檢索新的數(shù)據(jù)，而無(wú)需重新 加載所有的內(nèi)容，從而加快了 web應(yīng)用程序的性能，響應(yīng)性和交互性更新網(wǎng)頁(yè)。ajax開(kāi)

5、發(fā)工具一些廠(chǎng)商和組織都開(kāi)發(fā)了自己的基于ajax的平臺(tái)?！败浖I(yè)的歷史清楚地說(shuō) 明了平臺(tái)的重要性，就如同明確的威脅互聯(lián)網(wǎng)代表到這些平臺(tái)。因此，供應(yīng)商正 在加速引進(jìn)了利用網(wǎng)絡(luò)，而促進(jìn)自己的工具和技術(shù)平臺(tái)。在為了爭(zhēng)取自己的未 來(lái)的相關(guān)性，“分析師市場(chǎng)研究公司redmonk的斯蒂芬說(shuō)。ajax平臺(tái)有助于簡(jiǎn) 化車(chē)削應(yīng)用概念變?yōu)槌善穜1a的過(guò)程。它們包括腳本庫(kù)，即在服務(wù)器上運(yùn)行的 代碼片段，或者和一個(gè)集成開(kāi)發(fā)環(huán)境或插件流行的ide,比如eclipseo在本質(zhì)上，服務(wù)器運(yùn)行的ria的后端，庫(kù)創(chuàng)建訪(fǎng)問(wèn)經(jīng)由所述瀏覽器的應(yīng)用程 序的客戶(hù)端代碼,和顯影框架使程序的建筑物。開(kāi)源ajax的環(huán)境包括appcelerato

6、r 的appcelerator,道場(chǎng)基金會(huì)的dojo匸具包,拉茲洛系統(tǒng)的openlaszlo和nexaweb technologies 的 nexaweb o谷歌web工具包gwt是一個(gè)開(kāi)源的java軟件開(kāi)發(fā)框架，可以讓web開(kāi)發(fā)人員使用java創(chuàng) 建ajax應(yīng)用程序。它包括開(kāi)發(fā)人員使用的代碼庫(kù)。gwt的一個(gè)優(yōu)點(diǎn)是，當(dāng)建設(shè) 是開(kāi)發(fā)人員可以利用廣泛的java工具生態(tài)系統(tǒng)。該工具包編譯器開(kāi)啟了 java代 碼轉(zhuǎn)換成純javascript代碼，谷歌的gwt工程經(jīng)理bruce johnson說(shuō)。代碼被設(shè) 計(jì)為與谷歌的jaw服務(wù)器運(yùn)行時(shí)引擎交互，并為尺寸和效率進(jìn)行了優(yōu)化。除了 創(chuàng)建完整的應(yīng)用程序，開(kāi)發(fā)者

7、還可以構(gòu)建ria的功能位到網(wǎng)頁(yè)中使用gwto微軟 asp.net ajax微軟的應(yīng)用程序開(kāi)發(fā)工具戰(zhàn)略的一個(gè)關(guān)鍵組成部分是asp.net ajax的，其中 包括微軟公司的asp。建立動(dòng)態(tài)web應(yīng)用程序，網(wǎng)站和web服務(wù)網(wǎng)絡(luò)服務(wù)器環(huán) 境。visual studio是微軟用于創(chuàng)建跨asp.net和客戶(hù)端運(yùn)行的應(yīng)用程序的開(kāi)發(fā)環(huán) 境。ajax擴(kuò)展讓從瀏覽器與ajax引擎運(yùn)行visual studio應(yīng)用程序并連接到一個(gè) asp.net服務(wù)器。有了這些擴(kuò)展，.net開(kāi)發(fā)人員可以利用他們現(xiàn)有的技能，工 具和服務(wù)器基礎(chǔ)架構(gòu)創(chuàng)建ajax應(yīng)用程序，微軟的高級(jí).net平臺(tái)戰(zhàn)略經(jīng)理克里 斯斯文森解釋道。asp.net

8、 ajax的支持多種瀏覽器。優(yōu)點(diǎn)和缺點(diǎn)專(zhuān)有的ajax替代承諾更好的圖形元素的更快，更具互動(dòng)性的用戶(hù)界面， burton集團(tuán)克內(nèi)恩席爾徳指岀。由于基于ajax的方法通過(guò)在web瀏覽器上運(yùn)行, 他們沒(méi)有使用一個(gè)無(wú)狀態(tài)的編程模型，例如，提供了一個(gè)標(biāo)準(zhǔn)的方法來(lái)緩存客戶(hù) 端狀態(tài)數(shù)據(jù)。此外，web服務(wù)器必須為毎一個(gè)客戶(hù)端會(huì)話(huà)。專(zhuān)有的ria方法， 在另一方面，使用有狀態(tài)的編程模型?？蛻?hù)可以接管許多工作，這從對(duì)等功能存 儲(chǔ)責(zé)任釋放的web服務(wù)器。另外，每個(gè)客戶(hù)維護(hù)它自己的會(huì)話(huà)。這減輕了服務(wù) 器負(fù)擔(dān)，這可以保持用戶(hù)會(huì)話(huà)數(shù)量有限這一職責(zé)的。通過(guò)專(zhuān)有平臺(tái)上開(kāi)發(fā)的可以在本地存儲(chǔ)數(shù)據(jù)和區(qū)域一體化協(xié)定能夠更好地 挖掘到客

9、戶(hù)端的顯卡驅(qū)動(dòng)程序改進(jìn)的渲染和性能。因?yàn)闃?biāo)準(zhǔn)沒(méi)有充分發(fā)展，基于 ajax的平臺(tái)不能提供這些功能。使用專(zhuān)有的ajax的替代品，不過(guò)，用戶(hù)必須為 每個(gè)平臺(tái)下載，部署，管理，并定期更新一個(gè)不同的插件。此外，插件創(chuàng)建潛在 的安全問(wèn)題。使用專(zhuān)有方法可以在用戶(hù)訪(fǎng)問(wèn)特定的供應(yīng)商和平臺(tái)鎖定，nexaweb 首席技術(shù)官杰里米喬內(nèi)說(shuō)。許多開(kāi)發(fā)人員希望ajax的標(biāo)準(zhǔn)和技術(shù)的發(fā)展不犧牲開(kāi)放性和互操作性，以 提供更好的用戶(hù)體驗(yàn)和編程模型。目前，這些技術(shù)限制了圖形化應(yīng)用程序以木地 硬件資源的訪(fǎng)問(wèn)。并且在木地緩存的數(shù)據(jù)和狀態(tài)還沒(méi)有ajax的標(biāo)準(zhǔn)。為了解決 這個(gè)問(wèn)題，形成了被0penajax聯(lián)盟開(kāi)源團(tuán)體，供應(yīng)商和其他公司，該

10、集團(tuán)的 董事和ibm新興的互聯(lián)網(wǎng)技術(shù)集團(tuán)一個(gè)web設(shè)計(jì)師喬恩費(fèi)拉約洛說(shuō)。ajax使用可能會(huì)約在ria的問(wèn)題的擔(dān)憂(yōu)限制如即有機(jī)會(huì)獲得一個(gè)硬盤(pán)驅(qū)動(dòng) 器或其它本地資源，nexaweb的喬內(nèi)解釋說(shuō)。而且，redmonk公司的奧格雷迪 說(shuō)，許多ria開(kāi)發(fā)平臺(tái)仍然有問(wèn)題，如不同的瀏覽器，文檔缺點(diǎn)，采用有限支 持技術(shù)以不同的方式運(yùn)行的應(yīng)用程序。asp.net 支持 xml web services。xml web services 是包含業(yè)務(wù)功 能的組 件，利用該業(yè)務(wù)功能，應(yīng)用程序可以使用http和xml消息等標(biāo)準(zhǔn)跨越防火墻 交換信息。xml web services不用依靠特定的組件技術(shù)或?qū)ο笳{(diào)用約定。因

11、此， 用任何語(yǔ)言編寫(xiě)、使用任何組件模型并在任何操作系統(tǒng)上運(yùn)行的程序，都可以訪(fǎng)問(wèn) xml web services oasp.net包括一個(gè)可擴(kuò)展的宿主環(huán)境，該環(huán)境控制應(yīng)用程序的生命周期，即 從用戶(hù)首次訪(fǎng)問(wèn)此應(yīng)用程序中的資源（例如頁(yè)）到應(yīng)用程序關(guān)閉這一期間。雖 然asp.net依賴(lài)作為應(yīng)用程序宿主的web服務(wù)器（iis）,但asp.net白身也提 供了許多宿主功能。通過(guò)asp.net的基礎(chǔ)結(jié)構(gòu)，您可以響應(yīng)應(yīng)用程序事件并創(chuàng) 建自定義http處理程序和http模塊。asp.net中提供了對(duì)創(chuàng)建web服務(wù)器控件設(shè)計(jì)器（用于可視化設(shè)計(jì)工具， 例如visual studio）的增強(qiáng)支持。使用設(shè)計(jì)器可以為控

12、件生成設(shè)計(jì)時(shí)用戶(hù)界面， 這樣開(kāi)發(fā)人員可以在可視化設(shè)計(jì)工具中配置控件的屬性和內(nèi)容。c#是一種簡(jiǎn)潔、類(lèi)型安全的面向?qū)ο蟮恼Z(yǔ)言，開(kāi)發(fā)人員可以使用它來(lái)構(gòu)建 在.net framework ±運(yùn)行的各種安全、可靠的應(yīng)用程序。使用c#,您可以創(chuàng)建 傳統(tǒng)的windows客戶(hù)端應(yīng)用程序、xml web services分布式組件、客戶(hù)端服 務(wù)器應(yīng)用程序、數(shù)據(jù)庫(kù)應(yīng)用程序以及很多其他類(lèi)型的程序。 microsoft visual c# 2005提供高級(jí)代碼編輯器、方便的用戶(hù)界面設(shè)計(jì)器、集成調(diào) 試器和許多其他工具，以在c#語(yǔ)言版本2.0和.net framework的基礎(chǔ)上加快應(yīng) 用程序的開(kāi)發(fā)。c#語(yǔ)法表

13、現(xiàn)力強(qiáng)，只有不到90個(gè)關(guān)鍵字，而且簡(jiǎn)單易學(xué)。c#的大括號(hào)語(yǔ)法 使任何熟悉c、c+或java的人都可以立即上手。了解上述任何一種語(yǔ)言的開(kāi) 發(fā)人員通常在很短的時(shí)間內(nèi)就可以開(kāi)始使用c#高效地工作。c#語(yǔ)法簡(jiǎn)化 了 c+的諸多復(fù)雜性，同時(shí)提供了很多強(qiáng)大的功能，例如可為空的值類(lèi)型、枚 舉、委托、匿名方法和直接內(nèi)存訪(fǎng)問(wèn)，這些都是java所不具備的。c#還支持泛 型方法和類(lèi)型，從而提供了更出色的類(lèi)型安全和性能。c#還提供了迭代器，允 許集合類(lèi)的實(shí)現(xiàn)者定義自定義的迭代行為，簡(jiǎn)化了客戶(hù)端代碼對(duì)它的使用。2 外文原文new ways to build rich internet applicationsgeorg

14、e lawtonrich internet applica-tions一which have many of the features and func-tionality of desktop soft-ware even though they run onlinehave become increas-ingly important and popular.rias feature responsive user interfaces and interactive capabilities- this makes internet-based programs easier to us

15、e and more functional, and also overcomes problems with traditional web applications such as slow performance and limited inter-activity.however, these programs are trickier to develop than traditional applications, noted david temkin, chief technical officer of ria plat-form vendor laszlo systems.f

16、or example, the web is stateless. online, the web server, not the client, generally saves a transaction state. scaling problems can occur when the server must maintain a session for each of many ria users, said kirk kno-ernschild, an analyst with the burton group, a market research firm.by 2005, dev

17、elopers were learn-ing how to use ajax (asynchronous javascript and xml) to create a desktop-like interface in applica-tions such as google maps. they have subsequently used it to create entire enterprise rias.several vendors have recently released their own ajax-based ria-development platforms, inc

18、luding microsofvs asp.net ajax and the google web toolkit.other companies have released ria platforms not based on ajax, such as adobe systems' flash and air (adobe integrated runtime), microsoft silverlight, and sun microsystems5 javafx.these approaches have expanded on ajax functionality, enab

19、led com-panies to use ajax to make their own application-development products more appealing, or let vendors put their own spin on ria development.rich internet applicationsrias generally have clients handle user-interface-related activity, while the application server processes and stores data and

20、streamlines data updates sent to the client. this frees server resources, allowing the same hardware to handle more client ses-sions concurrently. it also reduces client-server traffic, resulting in bet-ter performance.an ria typically, though not always, runs within a browser and doesnt require sof

21、tware installa-tion on the client for security, most rias run their client elements within a sandbox.rias typically feature asynchro-nous communication, in which the client engine can interact with the server without waiting for the user to perform an action such as click-ing on a link. this increas

22、es respon-siveness, as users don't have to wait for data to move between client and serve匚 for example, users can manipulate a google maps display without waiting for pages to reload each time.ajaxjesse james garrett, president of the adaptive path product-design consultancy, coined the acronym

23、ajax in 2005. however, companies actually began working with the technology several years earlie匚ajax applications generally cre-ate javascript-based code that runs within the browser engine. the engine intercepts user inputs, dis-plays requested material, and han-dles interactions on the client sid

24、e. if the engine needs more data, it requests material from the server in the background, letting the user con-tinue to interact with the program.the process utilizes asynchronous javascript, which an html page can use to make calls to the web server to fetch documents. this lets an application make

25、 a server call, retrieve new data, and update the webpage without reloading all of the contents, which speeds up web applications5 performance, respon-siveness, and interactivity.ajax development toolsseveral vendors and organizations have developed their own ajax-based platforms.“the history of the

26、 software indus-try clearly illustrates the importance of platforms and just as clearly the threat the internet represents to these platforms. thus, vendors are hasten-ing to introduce platforms that lever-age the network while promoting their own tools and technologies.in an attempt to secure their

27、 future relevance/' said stephen o5grady, analyst with market-research firm redmonk.the ajax platforms help simplify the process of turning an applica-tion concept into a finished ria. they include scripting libraries, code snippets that run on the server, and either an integrated development en

28、vironment or plug-ins to popular ides such as eclipse.in essence, the server runs the rlvs back end, the libraries cre-ate the client code that accesses the applications via the browser, and the development framework enables the building of programs.open source ajax environments include appcelerator

29、s appcelerator, the dojo foundation dojo toolkit, laszlo systems openlaszlo, and nexaweb technologies nexaweb.google web toolkitgwt is an open source java soft-ware-development framework that lets web developers use java to cre-ate ajax applications. it includes code libraries for use by developers.

30、an advantage of gwt is that developers can leverage the extensive java tools ecosystem when building rias.the toolkit's compiler turns the java code into pure javascript code, said bruce johnson, google's gwt engineering manager. the code is designed to interact with googled java server runt

31、ime engine and is optimized for size and efficiency.in addition to creating full applica-tions, developers can also build bits of ria functionality into web pages with gwt.microsoft asp.net ajaxa key component of microsoft application-development tool strat-egy is asp.net ajax, which consists of ext

32、ensions to the company asp. net server environment for building dynamic web applications, websites, and web services.visual studio is microsoft development environment for creating applications that run across asp.net and a client. the ajax extensions let visual studio applications run from a browse

33、r with an ajax engine and connect to an asp.net serve匚with these extensions, .net devel-opers can leverage their existing skills, tools, and server infrastruc-tures to create ajax applications, explained chris swenson, micro-softs senior .net platform strategy manage匚asp.net ajax supports multiple b

34、rowsers.pros and consthe proprietary ajax alternatives promise a faster, more interactive user interface with better graphics elements, noted the burton groups knoernschild.because ajax-based approaches run via the browser across the web, they use a stateless programming model, which doesn't, fo

35、r example, provide a standard way to cache state data on the client. in addition, web servers must maintain sessions for each client.proprietary ria approaches, on the other hand, use a stateful pro-gramming model. clients can take over much of the work, which frees the web server from responsibil-i

36、ty for functions such as storage. in addition, each client maintains its own session. this relieves serv-ers, which can maintain sessions for only a limited number of users, of this responsibility.rias developed via proprietary platforms can store data locally and are better able to tap into the cli

37、ents graphics drivers for improved ren-dering and performance.ajax-based platforms can?t offer these capabilities because the stan-dards have not evolved sufficiently.with proprietary ajax alterna-tives, however, users must down-load, deploy, manage, and regularly update a different plug-in for each

38、 platform. in addition, plug-ins cre-ate potential security problems.moreover, using proprietary approaches can lock in users to spe-cific vendors and platforms, said nexaweb chief technology officer jeremy chone.many developers hope that ajax standards and technologies evolve to provide better user

39、 experiences and programming models without sacrificing open-ness and interoperability.currently, these technologies limit graphical applications5 access to local hard-ware resources- and there are no ajax standards yet for locally cach-ing data and state.to help with this, open source groups, vendo

40、rs, and other compa-nies formed the openajax alliance, said jon ferraiolo, the group's direc-tor and a web architect with ibnts emerging internet technologies group.ajax use could be limited by con-cerns about rias over issues such as the security of applications that have access to a hard drive

41、 or other local resources, noted nexaweb's chone.and, said redmonk9s o'grady, many ria-development platforms still have problems such as applica-tions running differently on differ-ent browsers, documentation short-comings, and limited adoption of the supporting technologies.asp.net supports

42、 xml web services. xml web services is the component that contains the business function, the use of the service function, an application can use http and xml messaging standard across the firewall to exchange information. xml web services do not rely on a particular component technology or object-c

43、alling convention. thus, in any language, using any component model, and running on any operating system programs can access xml web services.asp.net includes a scalable hosting environment that control of the application life cycle, from the user's first visit to this application resources (suc

44、h as pages) to the application is closed during the period. although asp.net applications rely as host web server (iis), asp.net itself but also provides a number of host functions. by infrastructure asp-net, you can respond to application events and create custom http handlers and http modules.asp.net is provided (such as visual studio for visualization design tool) enhanced support for creating web server control designer. you can use th