外文翻译-基于web的高校学生档案管理系统

0外文原文Asallreadersknow,HTMLisatthefoundationoftheWeb.Throughthemechanismofhyperlinks,HTMLenablestexttobeorganizedinnonlinearwayssomethingthatisnotpossiblewiththetraditional,top-downrepresentation.Becauseofthepowerofhyperlinks,HTMLisbeingusedinincreasingnumbersofnon-Web-relatedapplications,too.Forexample,todaymanyHelpfilesuseHTMLtorepresenttheirinformation.BecauseoftheimportanceofHTMLtothemoderncomputingenvironment,itisnotuncommontoencounterasituationinwhichtherenderingofHTMLiseitherrequiredordesired.Inthepast,suchataskwaschallengingbecauseoftherichnessoftheHTMLcommandsetandtheneedtoprocesshyperlinks.Fortunately,Javasimplifiesthistask,althoughnotallJavaprogrammersareawareofit.SupportforHTMLisincludedintheSwingframework.Thissupportincludestheabilitytodisplay(render)HTMLandhandlehyperlinkeventnotifications.HTMLcanberenderedbytheJEditorPaneclass.HyperlinkeventsaremanagedviatheHyperlinkEventclassandTheHyperlinkListenerinterface.Javasbuilt-insupportforHTMLisacapabilitythatisoftenoverlooked.ThischapterbeginsbydescribinghowtorenderHTMLbyusingJEditorPaneandhowtohandlehyperlinkevents.ItthendemonstratesthesecapabilitiesbycreatingasimpleWebbrowser.Ofcourse,therenderingofHTMLisnotlimitedtobrowsers.YoucanusethetechniquesdescribedherewheneveryouneedtodisplayandprocessHTML.SwingsJEditorPaneclassmakestherenderingofHTMLeasy.SimplyinstantiateaJEditorPaneandthensetitscontenttypetotext/html.WhendisplayingHTML,youwillalsoneedtodisableediting.Thefollowingsequenceshowstheproceduretofollow:JEditorPanehtmlViewer=newJEditorPane();htmlViewer.setContentType(text/html);htmlViewer.setEditable(false);AfterinstantiatingaJEditorPaneinstancecalledhtmlViewer,setContentType()iscalledtocausehtmlViewertorenderitscontentasHTML.CallingsetEditable()withaparameteroffalsepreventsthecontentsoftheeditorpanefrombeingchanged.ItalsoallowsHTMLtagstoberenderedratherthandisplayedastags.ThesestepsareallthatisrequiredtoprepareaJEditorPaneforrenderingHTMLandareaperfectexampleoftheartofJava!Anotherbonuswiththiseditionisthefreemultimediaseminarthatyoucandownloadfromwww.MindV.ThisistheThinkinginCseminarthatgivesyouanintroductiontotheCsyntax,operators,andfunctionsthatJavasyntaxisbasedupon.InpreviouseditionsofthebookthiswasintheFoundationsforJavaCDthatwaspackagedwiththebook,butnowtheseminarmaybefreelydownloaded.IoriginallycommissionedChuckAllisontocreateThinkinginCasastandaloneproduct,butdecidedtoincludeitwiththe2ndeditionofThinkinginC+and2ndand3rdeditionsofThinkinginJavabecauseoftheconsistentexperienceofhavingpeoplecometo1seminarswithoutanadequatebackgroundinbasicCsyntax.Thethinkingapparentlygoes“ImasmartprogrammerandIdontwanttolearnC,butratherC+orJava,soIlljustskipCandgodirectlytoC+/Java.”Afterarrivingattheseminar,itslowlydawnsonfolksthattheprerequisiteofunderstandingCsyntaxisthereforaverygoodreason.Technologieshavechanged,anditmademoresensetoreworkThinkinginCasadownloadableFlashpresentationratherthanincludingitasaCD.Byprovidingthisseminaronline,Icanensurethateveryonecanbeginwithadequatepreparation.TheThinkinginCseminaralsoallowsthebooktoappealtoawideraudience.EventhoughtheOperatorsandControllingExecutionchaptersdocoverthefundamentalpartsofJavathatcomefromC,theonlineseminarisagentlerintroduction,andassumesevenlessaboutthestudentsprogrammingbackgroundthandoesthebook.Ifascriptinglanguagecansolve80percentoftheclient-sideprogrammingproblems,whatabouttheother20percentthe“reallyhardstuff?”ThemostpopularsolutiontodayisJava.Notonlyisitapowerfulprogramminglanguagebuilttobesecure,cross-platform,andinternational,butJavaisbeingcontinuallyextendedtoprovidelanguagefeaturesandlibrariesthatelegantlyhandleproblemsthataredifficultintraditionalprogramminglanguages,suchasmultithreading,databaseaccess,networkprogramming,anddistributedcomputing.Javaallowsclient-sideprogrammingviatheapplet.Anappletisamini-programthatwillrunonlyunderaWebbrowser.TheappletisdownloadedautomaticallyaspartofaWebpage(justas,forexample,agraphicisautomaticallydownloaded).Whentheappletisactivateditexecutesaprogram.Thisispartofitsbeautyitprovidesyouwithawaytoautomaticallydistributetheclientsoftwarefromtheserveratthetimetheuserneedstheclientsoftware,andnosooner.Theusergetsthelatestversionoftheclientsoftwarewithoutfailandwithoutdifficultreinstallation.BecauseofthewayJavaisdesigned,theprogrammerneedstocreateonlyasingleprogram,andthatprogramautomaticallyworkswithallcomputersthathavebrowserswithbuilt-inJavainterpreters.(Thissafelyincludesthevastmajorityofmachines.)SinceJavaisafull-fledgedprogramminglanguage,youcandoasmuchworkaspossibleontheclientbeforeandaftermakingrequestsoftheserver.Forexample,youwontneedtosendarequestformacrosstheInternettodiscoverthatyouvegottenadateorsomeotherparameterwrong,andyourclientcomputercanquicklydotheworkofplottingdatainsteadofwaitingfortheservertomakeaplotandshipagraphicimagebacktoyou.Notonlydoyougettheimmediatewinofspeedandresponsiveness,butthegeneralnetworktrafficandloadonserverscanbereduced,preventingtheentireInternetfromslowingdown.OneadvantageaJavaapplethasoverascriptedprogramisthatitsincompiledform,sothesourcecodeisntavailabletotheclient.Ontheotherhand,aJavaappletcanbedecompiledwithouttoomuchtrouble,buthidingyourcodeisoftennotanimportantissue.2Twootherfactorscanbeimportant.Asyouwillseelaterinthisbook,acompiledJavaappletcancomprisemanymodulesandtakemultipleserver“hits”(accesses)todownload.(InJava1.1andhigherthisisminimizedbyJavaarchives,calledJARfiles,thatallowalltherequiredmodulestobepackagedtogetherandcompressedforasingledownload.)AscriptedprogramwilljustbeintegratedintotheWebpageaspartofitstext(andwillgenerallybesmallerandreduceserverhits).ThiscouldbeimportanttotheresponsivenessofyourWebsite.Anotherfactoristheall-importantlearningcurve.Regardlessofwhatyouveheard,Javaisnotatriviallanguagetolearn.IfyoureaVisualBasicprogrammer,movingtoVBScriptwillbeyourfastestsolution,andsinceitwillprobablysolvemosttypicalclient/serverproblemsyoumightbehardpressedtojustifylearningJava.IfyoureexperiencedwithascriptinglanguageyouwillcertainlybenefitfromlookingatJavaScriptorVBScriptbeforecommittingtoJava,sincetheymightfityourneedshandilyandyoullbemoreproductivesooner.torunitsappletswithi3中文翻译由于所有的读者都知道，HTML是在Web的基础。通过超链接的机制，允许的HTML文本，将组织在非线性的方式，东西是不可能与传统的，自上而下的代表性。因为超链接的力量，HTML是被增加的非Web相关的数字用应用了。例如，现在很多的帮助文件使用HTML来表示他们的信息。因为HTML的现代计算环境的重要性，这是不寻常遇到的情况是，要么需要或期望的HTML的渲染。在过去，这样的任务是因为HTML令集的丰富性和挑战性需要处理的超链接。幸运的是，Java的简化了这个任务，虽然不是所有的Java程序员都知道这一点。支持HTML包含在Swing框架。这种支持包括能力显示（渲染）HTML和处理超链接事件的通知。HTML可以呈现由theJEditorPane类。超链接事件通过theHyperlinkEvent类和管理theHyperlinkListener接口。Java的内置支持HTML是一种能力，那就是往往被忽视。本章首先描述如何呈现HTML由usingJEditorPane以及如何处理超链接事件。它通过创建一个简单的Web然后演示了这些功能浏览器。当然，HTML的呈现不限于浏览器。您可以使用技巧这里描述的，当您需要显示和处理的HTMLSwingsJEditorPane类使得HTML的渲染容易。简单地实例化一个JEditorPane中，然后设置其内容类型为“text/html的”。当显示的HTML，你还需要禁用编辑。下面的顺序显示遵循的程序：JEditorPane中htmlViewer=新的JEditorPane（）;htmlViewer.setContentType（“text/html的”）;htmlViewer.setEditable（假）;实例aJEditorPane例如calledhtmlViewer，的setContentType（后）被称为到causehtmlViewer呈现其作为HTML内容。CallingsetEditable（），其参数假防止被更改编辑器窗格中的内容。它还允许HTML标签呈现，而不是显示为标记。这些步骤所需要的所有准备aJEditorPane渲染HTML和是Java的艺术的一个很好的例子！因为有市民前来研讨会在没有基本的C语法足够的背景一致的体验，在Java中的思考。这一思想显然是去“我是一个聪明的程序员，我不想学C，而C+或Java的，所以我就跳过C和直接进入到C+/Java的。”抵达研讨会后，慢慢地洒在人们的理解C语法的前提是有一个很好的理由。技术已经改变了，而且更有意义返工C语言思考作为一个可下载的Flash演示文4稿，而不是把它作为一个光盘。通过网上提供这个研讨会，我可以保证每个人都可以有足够的准备开始。C语言研讨会的思考也让这本书以吸引更广泛的受众。尽管运营商和控制执行的章节做涵盖了Java的是来自C中的基本组成部分，网上研讨会是一个温和的介绍，并假定甚至少谈学生的编程背景并不比书。在网上，我可以保证每个人都可以有足够的准备开始。C语言研讨会的思考也让这本书以吸引更广泛的受众。尽管运营商和控制执行的章节做涵盖了Java的是来自C中的基本组成部分，网上研讨会是一个温和的介绍，并假定甚至少谈学生的编程背景并不比书。如果说一种脚本编制语言能解决80的客户端程序设计问题，那么剩下的20又该怎么办呢？它们属于一些高难度的问题吗？目前最流行的方案就是Java。它不仅是一种功能强大、高度安全、可以跨平台使用以及国际通用的程序设计语言，也是一种具有旺盛生命力的语言。对Java的扩展是不断进行的，提供的语言特性和库能够很好地解决传统语言不能解决的问题，比如多线程操作、数据库访问、连网程序设计以及分布式计算等等。Java通过“程序片”（Applet）巧妙地解决了客户端编程的问题。程序片（或“小应用程序”）是一种非常小的程序，只能在Web浏览器中运行。作为Web页的一部分，程序片代码会自动下载回来（这和网页中的图片差不多）。激活程序片后，它