JAVA教程之JAVA程序员眼里的C#

在1995年5月23日以“Java”的名称正式发布了。程序|程序员JavadevelopersviewofC#.
September03,2004
Therearetwowaystocompareprogramminglanguages:areligiouswaranda"wejustdontcare"typeofattitude.Iwilltrytofindthemiddlegroundandstartwithgeneralities.ThekeyfeatureofbothJavaandC#isautomatedmemorymanagement.Ofcoursethismakesbothlanguagesuselessforwritinganoperatingsystemkernel,butitmakesapplicationdevelopmentsignificantlyeasierbecause

Chancesofamemoryleakareminimized
Wedonthavetowritecodetofreeupmemory
Wecanwritef(g(x))andnotworryaboutfreeingupmemoryusedbythereturnvalueofg(x).
So,wehavetwopopularsoftwaredevelopmentplatforms.Eachofthetwoisusedbymillionsofsoftwaredevelopersandisbackedbyaworldfamoussoftwaregiant,butneitheronecarriesanyrevolutionaryadvantages.



InfluenceofMicrosoft
HistoricallyJavacameaboutearlierthan.NETandslowlycapturednotonlytheserver-sidesoftwaremarket,butalsothemarketofcorporateclientorientedGUIapplications.ThereasonswerethatC++istoocomplexformakingforms,VisualBasicdoesntfeellikeacooldeveloperslanguage,andBorlandinvestedmoreintoJavathanintoDelphi.

However,themoreJavaapplicationsthereare,thesmallerthedemandforWindows.SoMicrosoftdecidednottosupportJava,andtocreate.NETinordertostimulatethedevelopmentofsoftwaredesignedtorunonWindows.Ofcourse.NEThassomecross-platformcompatibility,butfromthepointofviewofWindows,.NETistryingtobecomeapartoftheoperatingsystemlikeInternetExplorer.Thecareerofa.NETdevelopersupposesaclosepartnershipwithMicrosoftincludingtheuseoftheVisualStudioDevelopmentEnvironment,MSSQLdatabase,andtheversioningcontrolsystemVisualSourceSafe.

MicrosoftmarketingdeservesalotofcreditforthefactthatmanysoftwaredevelopmentcompaniestendtothinkaboutsoftwareentirelywithintheMicrosoftframework.Becauseofthat,sometimeswehavetoputasidebelovedJava,andmakeuseofC#.Thegoodnewsis,theexperiencegainedwhileworkingwithJavaishelpfulwith.NET,anddevelopmentof.NETismotivatingprogressofJava.



CVSvs.VSS
ThemajorityofJavadevelopershavegottenusedtoCVS,afterwhichamovetoVisualSourceSafecombinedwithitsintegrationintoVisualStudioandthesolutions-projectsconceptisperceivedasquitepainful.TobefairwemustnotethattheuseofCVSinalargeprojectistheoreticallypossible,buttriggersanegativereactionofpeople,usedtoworkingwithVSS.

HereIcouldthrowsomepunchesonthesubjectof"whyisCVSbetterthanVSS",butIwillnotdothatbecauseCVSisntperfecteither.Thenthereisaprojectcalled"Subversion"whichisopenlypositionedasthereplacementforCVS.NeitherdoesMicrosoftconsiderVSSasitsflagshipproduct,andisworkingonareplacementforitintheformoftheVisualStudio2005TeamSystem.



TheinfluenceofVB.NET
ManylanguagescanbecompiledintobytecodeforJVM,butpracticallyallthesoftwarefortheJavaplatformiswritteninJavaitself.Aprojectfor.NETcanequallylikelybewrittenineitherC#orVB.NET,andquiteoftenbothlanguagesareused.

ClearlyC#andVB.NEThaveveryfewdifferences,exceptforthesyntax,butcreateadivideinthecommunityofdevelopers.EvenifyouwriteexclusivelyinC#,intheresultsofasupportdocumentationsearchyouwillalwaysfindmaterialrelatedtoVB.NET.InadesktopversionofMSDNonecanfilterthecontentbyprogramminglanguage,yetIstillfindtheJavadocumentationmuchmoreconvenientandhelpful.



GUIdevelopment
GUIdevelopmentinC#isatypicalexampleofRAD,likeDelphi.InJavatheGUIisusuallydonewithSwing.EventhoughSwingisquitelargeandcomplex,thefactthatthearchitectureiswellthoughtoutandscalablecombinedwiththeavailabilityofthesourcecodeallowsfordevelopmentofGUIofanycomplexity.



Webapplicationdevelopment
IhavealotofexperienceinwebapplicationdevelopmentinJava,andneverhaveIworkedwithASP.NET.HoweverIreadilyacceptASP.NEThavingsomeminoradvantageswhenitcomestocreatingsmallscalewebsites.Howevertheseadvantagesseparateweb-applicationsintoadistinctsegmentofsoftware.ManydevelopersspecializeineitherwebdevelopmentorGUIdevelopment.InJavaweb-applicationscaneasilybecreatedwithouttheuseofspecialtechnologieslikeJSP,JSTLorStruts.AllyouhavetosayisextendsHttpServlet.

OfcourseJavawillnoteasilygiveupthemarketofwebdevelopment.WecanexpectmorenewsfromJavaServerFacesandFabrique.Inanycasewebpagedevelopmentisnotamongthemostcomplicatedproblemsforamodernprogramminglanguage.



Iseverythingobject?
InJavathereisapopularslogan"Everythingisobject",inC#thiswouldnotbetrue.ThefirstthingthatstandsoutistheexistenceofstructuresinC#.Obviouslywearemotivatedtousestructurestoincreaseproductivity,butIthinkmoderncomputersareproductiveenoughnottorequiretheadditionofanotherentityinaprogramminglanguage.

AlsoanonymousclassesarereplacedbydelegatesinC#.Thisistheideathatifamethodhasadefinitesetofargumentsandagivenreturntype,itisabsolutelyunimportantwhatitsnameisandwhetherornotitisstatic,oranyothernonsense.Youcanjustcallit.

Whileweareonthesubjectofdelegates,weshouldalsomentionevents.TheyreallydodecreasethecodevolumeinGUIdevelopment.HoweverthiscomesatapriceofgoingagainstOOPprinciples.

InadditionC#hassomeaddedabilities,whicharenotpresentinJava.Withoutgoingintomuchdetail,Iwillmentionoperatoroverloading,andkeywordssuchasvirtual,override,ref,outandparam.



Theinfluenceofthedevelopmentplatformontheprogrammersself-consciousness
Withoutadoubt,theonethingthatinfluencesthequalityofsoftwareisthequalityofsoftwaredevelopers,andnottheprogramminglanguage.Nevertheless,myexperiencetellsmethatinthemajorityofJavaprojectsAntisusedforbuildmanagement.Ontheotherhandin.NET,buildsareoftendonewithtoolsbuiltintoVisualStudio,eventhoughanalogousinstrumentsexistfor.NET.Besides,C#doesnothaveclearrulesfornamingclassesandstoringthemondisk.Thisoftencreatesadditionalconfusion(whichqualifiedprogrammerssuccessfullyovercome).

C#doesnthavecheckedexceptions,thereasonsforwhichareexplainedhere.Thisdecisionhasitsreasons,butifthecompilerdoesntcontrolhandlingcheckedexception,thereneedstobemoreinformationonhowtoworkwitherrorsthroughothercommunicationchannels.Otherwisesomeprogrammerswillnotevenknowwhatexceptionsare.



Thetigersarechargingforward
TherearecertainareaswhereJavaisclearlydominating,forexamplecellularphonegamesandtheJavaCardtechnology.However,thestruggleformarketsharebetweenC#andJavawillgoonforalongtimetocome.Bothplatformswillbeimproved.ForexamplebothJava5and.NET2.0willsupportgenerics.

Itisobviousthatthesuccessofeveryindividualprojectwilldependnotontheprogramminglanguageused,butontheunderstandingofthetask,knowinghowtogiveunderstandablenamestomethods,abilitytoavoidrepetitiouscode,andotheruniversalvirtues.



Acknowledgements
IreallyappreciatethehelpofDmitryJemerov,thankstowhomyoudidnthavetoreadanyofthenonsensewhichIwroteatfirst.IalsothankDataArtcompany,whichgavemeachancetostudyC#onthejob,mycolleaguesatDataArt,whogavemeintellectualhelpandboostedmymoral,andtheJetBrainscompanyforgoodtimingindevelopingtheReSarpertool,whichallowsmetohavealmostasmuchfunwithC#asIamusedtohavingwithIntelliJIDEA.AspecialthankstoAlexeyPchelintsevforeditingtheRussianversionandtoPavelSokolovforthetranslation.



References

TheC#ProgrammingLanguageforJavaDevelopers
http://msdn.microsoft.com/vstudio/java/gettingstarted/csharpforjava/

J2EEfundamentalsfor.NETdevelopers
http://www-106.ibm.com/developerworks/java/library/j-roadmap1/
YakovSirotkin
SeniorDeveloper,DataArt

大型的应用一般不会用这些框架（因为性能考虑）；开发人员根据需要选择用一些框架，也可以不选用框架；不用框架并不代表要自己写框架；修改框架的可能性更小。

还好，SUN提供了Javabean可以把你的JSP中的 Java代码封装起来，便于调用也便于重用。

应用在电视机、电话、闹钟、烤面包机等家用电器的控制和通信。由于这些智能化家电的市场需求没有预期的高，Sun公司放弃了该项计划。随着1990年代互联网的发展

如果要向java web方向发展也要吧看看《Java web从入门到精通》学完再到《Struts2.0入门到精通》这样你差不多就把代码给学完了。有兴趣可以看一些设计模块和框架的包等等。

当然你也可以参加一些开源项目，一方面可以提高自己，另一方面也是为中国软件事业做贡献嘛！开发者在互联网上用CVS合作开发，用QQ,MSN,E-mail讨论联系，天南海北的程序员分散在各地却同时开发同一个软件，是不是很有意思呢？

其实说这种话的人就如当年小日本号称“三个月拿下中国”一样大言不惭。不是Tomjava泼你冷水，你现在只是学到了Java的骨架，却还没有学到Java的精髓。接下来你得研究设计模式了。

如果要向java web方向发展也要吧看看《Java web从入门到精通》学完再到《Struts2.0入门到精通》这样你差不多就把代码给学完了。有兴趣可以看一些设计模块和框架的包等等。

当然你也可以参加一些开源项目，一方面可以提高自己，另一方面也是为中国软件事业做贡献嘛！开发者在互联网上用CVS合作开发，用QQ,MSN,E-mail讨论联系，天南海北的程序员分散在各地却同时开发同一个软件，是不是很有意思呢？

还好，SUN提供了Javabean可以把你的JSP中的 Java代码封装起来，便于调用也便于重用。

Java自面世后就非常流行，发展迅速，对C++语言形成了有力冲击。Java 技术具有卓越的通用性、高效性、平台移植性和安全性，广泛应用于个人PC、数据中心、游戏控制台

如果你学过HTML，那么事情要好办的多，如果没有，那你快去补一补HTML基础吧。其实JSP中的Java语法也不多，它更象一个脚本语言，有点象ASP。

那么我书也看了，程序也做了，别人问我的问题我都能解决了，是不是就成为高手了呢？当然没那么简单，这只是万里长征走完了第一步。不信？那你出去接一个项目，你知道怎么下手吗，你知道怎么设计吗，你知道怎么组织人员进行开发吗？你现在脑子里除了一些散乱的代码之外，可能再没有别的东西了吧！

是一种突破用户端机器环境和CPU

《JAVA语言程序设计》或《JAVA从入门到精通》这两本书开始学，等你编程有感觉的时候也可以回看一下。《JAVA读书笔记》这本书，因为讲的代码很多，也很容易看懂，涉及到面也到位。是你学习技术巩固的好书，学完后就看看《JAVA编程思想》这本书，找找一个自己写的代码跟书上的代码有什么不一样。

Java 编程语言的风格十分接近C、C++语言。

关于设计模式的资料，还是向大家推荐banq的网站 [url]http://www.jdon.com/[/url]，他把GOF的23种模式以通俗易懂的方式诠释出来，纯Java描述，真是经典中的经典。

你现在最缺的是实际的工作经验，而不是书本上那些凭空想出来的程序。

应用在电视机、电话、闹钟、烤面包机等家用电器的控制和通信。由于这些智能化家电的市场需求没有预期的高，Sun公司放弃了该项计划。随着1990年代互联网的发展

仓酷云

一直感觉JAVA很大，很杂，找不到学习方向，前两天在网上找到了这篇文章，感觉不错，给没有方向的我指了一个方向，先不管对不对，做下来再说。

有时间再研究一下MVC结构（把Model-View-Control分离开的设计思想）