翻译文献-第10章 java io系统

外文原文11THEJAVAI/OSYSTEMCREATINGAGOODINPUT/OUTPUTI/OSYSTEMISONEOFTHEMOREDIFFICULTTASKSFORTHELANGUAGEDESIGNERTHISISEVIDENCEDBYTHENUMBEROFDIFFERENTAPPROACHESTHECHALLENGESEEMSTOBEINCOVERINGALLEVENTUALITIESNOTONLYARETHEREDIFFERENTSOURCESANDSINKSOFI/OTHATYOUWANTTOCOMMUNICATEWITHFILES,THECONSOLE,NETWORKCONNECTIONS,BUTYOUNEEDTOTALKTOTHEMINAWIDEVARIETYOFWAYSSEQUENTIAL,RANDOMACCESS,BUFFERED,BINARY,CHARACTER,BYLINES,BYWORDS,ETCTHEJAVALIBRARYDESIGNERSATTACKEDTHISPROBLEMBYCREATINGLOTSOFCLASSESINFACT,THEREARESOMANYCLASSESFORJAVASI/OSYSTEMTHATITCANBEINTIMIDATINGATFIRSTIRONICALLY,THEJAVAI/ODESIGNACTUALLYPREVENTSANEXPLOSIONOFCLASSESTHEREWASALSOASIGNIFICANTCHANGEINTHEI/OLIBRARYAFTERJAVA10,WHENTHEORIGINALBYTEORIENTEDLIBRARYWASSUPPLEMENTEDWITHCHARORIENTED,UNICODEBASEDI/OCLASSESASARESULTTHEREAREAFAIRNUMBEROFCLASSESTOLEARNBEFOREYOUUNDERSTANDENOUGHOFJAVASI/OPICTURETHATYOUCANUSEITPROPERLYINADDITION,ITSRATHERIMPORTANTTOUNDERSTANDTHEEVOLUTIONHISTORYOFTHEI/OLIBRARY,EVENIFYOURFIRSTREACTIONIS“DONTBOTHERMEWITHHISTORY,JUSTSHOWMEHOWTOUSEIT”THEPROBLEMISTHATWITHOUTTHEHISTORICALPERSPECTIVEYOUWILLRAPIDLYBECOMECONFUSEDWITHSOMEOFTHECLASSESANDWHENYOUSHOULDANDSHOULDNTUSETHEMTHISCHAPTERWILLGIVEYOUANINTRODUCTIONTOTHEVARIETYOFI/OCLASSESINTHESTANDARDJAVALIBRARYANDHOWTOUSETHEMTYPESOFINPUTSTREAMINPUTSTREAMSJOBISTOREPRESENTCLASSESTHATPRODUCEINPUTFROMDIFFERENTSOURCESTHESESOURCESCANBE1ANARRAYOFBYTES2ASTRINGOBJECT3AFILE4A“PIPE,”WHICHWORKSLIKEAPHYSICALEACHOFTHESEHASANASSOCIATEDSUBCLASSOFINPUTSTREAMINADDITION,THEFILTERINPUTSTREAMISALSOATYPEOFINPUTSTREAM,TOPROVIDEABASECLASSFOR“DECORATOR“CLASSESTHATATTACHATTRIBUTESORUSEFULINTERFACESTOINPUTSTREAMSTHISISDISCUSSEDLATERTABLE111TYPESOFINPUTSTREAMTYPESOFOUTPUTSTREAMTHISCATEGORYINCLUDESTHECLASSESTHATDECIDEWHEREYOUROUTPUTWILLGOANARRAYOFBYTESNOSTRING,HOWEVERPRESUMABLYYOUCANCREATEONEUSINGTHEARRAYOFBYTES,AFILE,ORA“PIPE”INADDITION,THEFILTEROUTPUTSTREAMPROVIDESABASECLASSFOR“DECORATOR“CLASSESTHATATTACHATTRIBUTESORUSEFULINTERFACESTOOUTPUTSTREAMSTHISISDISCUSSEDLATERTABLE112TYPESOFOUTPUTSTREAMADDINGATTRIBUTESANDUSEFULINTERFACESTHEUSEOFLAYEREDOBJECTSTODYNAMICALLYANDTRANSPARENTLYADDRESPONSIBILITIESTOINDIVIDUALOBJECTSISREFERREDTOASTHEDECORATORPATTERNPATTERNS57ARETHESUBJECTOFTHINKINGINPATTERNSWITHJAVA,DOWNLOADABLEATWWWBRUCEECKELCOMTHEDECORATORPATTERNSPECIFIESTHATALLOBJECTSTHATWRAPAROUNDYOURINITIALOBJECTHAVETHESAMEINTERFACETHISMAKESTHEBASICUSEOFTHEDECORATORSTRANSPARENTYOUSENDTHESAMEMESSAGETOANOBJECTWHETHERITSBEENDECORATEDORNOTTHISISTHEREASONFORTHEEXISTENCEOFTHE“FILTER”CLASSESINTHEJAVAI/OLIBRARYTHEABSTRACT“FILTER”CLASSISTHEBASECLASSFORALLTHEDECORATORSADECORATORMUSTHAVETHESAMEINTERFACEASTHEOBJECTITDECORATES,BUTTHEDECORATORCANALSOEXTENDTHEINTERFACE,WHICHOCCURSINSEVERALOFTHE“FILTER”CLASSESDECORATORSAREOFTENUSEDWHENSIMPLESUBCLASSINGRESULTSINALARGENUMBEROFSUBCLASSESINORDERTOSATISFYEVERYPOSSIBLECOMBINATIONTHATISNEEDEDSOMANYSUBCLASSESTHATITBECOMESIMPRACTICALTHEJAVAI/OLIBRARYREQUIRESMANYDIFFERENTCOMBINATIONSOFFEATURES,WHICHISWHYTHEDECORATORPATTERNISUSEDTHEREISADRAWBACKTOTHEDECORATORPATTERN,HOWEVERDECORATORSGIVEYOUMUCHMOREFLEXIBILITYWHILEYOUREWRITINGAPROGRAMSINCEYOUCANEASILYMIXANDMATCHATTRIBUTES,BUTTHEYADDCOMPLEXITYTOYOURCODETHEREASONTHATTHEJAVAI/OLIBRARYISAWKWARDTOUSEISTHATYOUMUSTCREATEMANYCLASSESTHE“CORE”I/OTYPEPLUSALLTHEDECORATORSINORDERTOGETTHESINGLEI/OOBJECTTHATYOUWANTTHECLASSESTHATPROVIDETHEDECORATORINTERFACETOCONTROLAPARTICULARINPUTSTREAMOROUTPUTSTREAMARETHEFILTERINPUTSTREAMANDFILTEROUTPUTSTREAMWHICHDONTHAVEVERYINTUITIVENAMESFILTERINPUTSTREAMANDFILTEROUTPUTSTREAMAREABSTRACTCLASSESTHATAREDERIVEDFROMTHEBASECLASSESOFTHEI/OLIBRARY,INPUTSTREAMANDOUTPUTSTREAM,WHICHISTHEKEYREQUIREMENTOFTHEDECORATORSOTHATITPROVIDESTHECOMMONINTERFACETOALLTHEOBJECTSTHATAREBEINGDECORATEDREADINGFROMANINPUTSTREAMWITHFILTERINPUTSTREAMTHEFILTERINPUTSTREAMCLASSESACCOMPLISHTWOSIGNIFICANTLYDIFFERENTTHINGSDATAINPUTSTREAMALLOWSYOUTOREADDIFFERENTTYPESOFPRIMITIVEDATAASWELLASSTRINGOBJECTSALLTHEMETHODSSTARTWITH“READ,”SUCHASREADBYTE,READFLOAT,ETCTHIS,ALONGWITHITSCOMPANIONDATAOUTPUTSTREAM,ALLOWSYOUTOMOVEPRIMITIVEDATAFROMONEPLACETOANOTHERVIAASTREAMTHESE“PLACES”AREDETERMINEDBYTHECLASSESINTABLE111THEREMAININGCLASSESMODIFYTHEWAYANINPUTSTREAMBEHAVESINTERNALLYWHETHERITSBUFFEREDORUNBUFFERED,IFITKEEPSTRACKOFTHELINESITSREADINGALLOWINGYOUTOASKFORLINENUMBERSORSETTHELINENUMBER,ANDWHETHERYOUCANPUSHBACKASINGLECHARACTERTHELASTTWOCLASSESLOOKALOTLIKESUPPORTFORBUILDINGACOMPILERTHATIS,THEYWEREADDEDTOSUPPORTTHECONSTRUCTIONOFTHEJAVACOMPILER,SOYOUPROBABLYWONTUSETHEMINGENERALPROGRAMMINGYOULLPROBABLYNEEDTOBUFFERYOURINPUTALMOSTEVERYTIME,REGARDLESSOFTHEI/ODEVICEYOURECONNECTINGTO,SOITWOULDHAVEMADEMORESENSEFORTHEI/OLIBRARYTOMAKEASPECIALCASEORSIMPLYAMETHODCALLFORUNBUFFEREDINPUTRATHERTHANBUFFEREDINPUTTABLE113TYPESOFFILTERINPUTSTREAMWRITINGTOANOUTPUTSTREAMWITHFILTEROUTPUTSTREAMTHECOMPLEMENTTODATAINPUTSTREAMISDATAOUTPUTSTREAM,WHICHFORMATSEACHOFTHEPRIMITIVETYPESANDSTRINGOBJECTSONTOASTREAMINSUCHAWAYTHATANYDATAINPUTSTREAM,ONANYMACHINE,CANREADTHEMALLTHEMETHODSSTARTWITH“WRITE,”SUCHASWRITEBYTE,WRITEFLOAT,ETCTHEORIGINALINTENTOFPRINTSTREAMWASTOPRINTALLOFTHEPRIMITIVEDATATYPESANDSTRINGOBJECTSINAVIEWABLEFORMATTHISISDIFFERENTFROMDATAOUTPUTSTREAM,WHOSEGOALISTOPUTDATAELEMENTSONASTREAMINAWAYTHATDATAINPUTSTREAMCANPORTABLYRECONSTRUCTTHEMTHETWOIMPORTANTMETHODSINPRINTSTREAMAREPRINTANDPRINTLN,WHICHAREOVERLOADEDTOPRINTALLTHEVARIOUSTYPESTHEDIFFERENCEBETWEENPRINTANDPRINTLNISTHATTHELATTERADDSANEWLINEWHENITSDONEBUFFEREDOUTPUTSTREAMISAMODIFIERANDTELLSTHESTREAMTOUSEBUFFERINGSOYOUDONTGETAPHYSICALWRITEEVERYTIMEYOUWRITETOTHESTREAMYOULLPROBABLYALWAYSWANTTOUSETHISWITHFILES,ANDPOSSIBLYCONSOLEI/OTABLE114TYPESOFFILTEROUTPUTSTREAMTYPICALUSESOFI/OSTREAMSALTHOUGHYOUCANCOMBINETHEI/OSTREAMCLASSESINMANYDIFFERENTWAYS,YOULLPROBABLYJUSTUSEAFEWCOMBINATIONSTHEFOLLOWINGEXAMPLECANBEUSEDASABASICREFERENCEITSHOWSTHECREATIONANDUSEOFTYPICALI/OCONFIGURATIONSNOTETHATEACHCONFIGURATIONBEGINSWITHACOMMENTEDNUMBERANDTITLETHATCORRESPONDSTOTHEHEADINGFORTHEAPPROPRIATEEXPLANATIONTHATFOLLOWSINTHETEXTINPUTSTREAMSPARTS1THROUGH4DEMONSTRATETHECREATIONANDUSEOFINPUTSTREAMSPART4ALSOSHOWSTHESIMPLEUSEOFANOUTPUTSTREAM1BUFFEREDINPUTFILETOOPENAFILEFORCHARACTERINPUT,YOUUSEAFILEINPUTREADERWITHASTRINGORAFILEOBJECTASTHEFILENAMEFORSPEED,YOULLWANTTHATFILETOBEBUFFEREDSOYOUGIVETHERESULTINGREFERENCETOTHECONSTRUCTORFORABUFFEREDREADERSINCEBUFFEREDREADERALSOPROVIDESTHEREADLINEMETHOD,THISISYOURFINALOBJECTANDTHEINTERFACEYOUREADFROMWHENYOUREACHTHEENDOFTHEFILE,READLINERETURNSNULLSOTHATISUSEDTOBREAKOUTOFTHEWHILELOOPTHESTRINGS2ISUSEDTOACCUMULATETHEENTIRECONTENTSOFTHEFILEINCLUDINGNEWLINESTHATMUSTBEADDEDSINCEREADLINESTRIPSTHEMOFFS2ISTHENUSEDINTHELATERPORTIONSOFTHISPROGRAMFINALLY,CLOSEISCALLEDTOCLOSETHEFILETECHNICALLY,CLOSEWILLBECALLEDWHENFINALIZERUNS,ANDTHISISSUPPOSEDTOHAPPENWHETHERORNOTGARBAGECOLLECTIONOCCURSASTHEPROGRAMEXITSHOWEVER,THISHASBEENINCONSISTENTLYIMPLEMENTED,SOTHEONLYSAFEAPPROACHISTOEXPLICITLYCALLCLOSEFORFILES2INPUTFROMMEMORYTHISSECTIONTAKESTHESTRINGS2THATNOWCONTAINSTHEENTIRECONTENTSOFTHEFILEANDUSESITTOCREATEASTRINGREADERTHENREADISUSEDTOREADEACHCHARACTERONEATATIMEANDSENDITOUTTOTHECONSOLENOTETHATREADRETURNSTHENEXTBYTEASANINTANDTHUSITMUSTBECASTTOACHARTOPRINTPROPERLY3FORMATTEDMEMORYINPUTIFYOUREADTHECHARACTERSFROMADATAINPUTSTREAMONEBYTEATATIMEUSINGREADBYTE,ANYBYTEVALUEISALEGITIMATERESULTSOTHERETURNVALUECANNOTBEUSEDTODETECTTHEENDOFINPUTINSTEAD,YOUCANUSETHEAVAILABLEMETHODTOFINDOUTHOWMANYMORECHARACTERSAREAVAILABLEHERESANEXAMPLETHATSHOWSHOWTOREADAFILEONEBYTEATATIME/C11TESTEOFJAVA/TESTINGFORTHEENDOFFILE/WHILEREADINGABYTEATATIMEIMPORTJAVAIOPUBLICCLASSTESTEOF/THROWEXCEPTIONSTOCONSOLEPUBLICSTATICVOIDMAINSTRINGARGSTHROWSIOEXCEPTIONDATAINPUTSTREAMINNEWDATAINPUTSTREAMNEWBUFFEREDINPUTSTREAMNEWFILEINPUTSTREAM“TESTEOFJAVA“WHILEINAVAILABLE0SYSTEMOUTPRINTCHARINREADBYTE/NOTETHATAVAILABLEWORKSDIFFERENTLYDEPENDINGONWHATSORTOFMEDIUMYOUREREADINGFROMITSLITERALLY“THENUMBEROFBYTESTHATCANBEREADWITHOUTBLOCKING”WITHAFILETHISMEANSTHEWHOLEFILE,BUTWITHADIFFERENTKINDOFSTREAMTHISMIGHTNOTBETRUE,SOUSEITTHOUGHTFULLYYOUCOULDALSODETECTTHEENDOFINPUTINCASESLIKETHESEBYCATCHINGANEXCEPTIONHOWEVER,THEUSEOFEXCEPTIONSFORCONTROLFLOWISCONSIDEREDAMISUSEOFTHATFEATURE4FILEOUTPUTTHISEXAMPLEALSOSHOWSHOWTOWRITEDATATOAFILEFIRST,AFILEWRITERISCREATEDTOCONNECTTOTHEFILEYOULLVIRTUALLYALWAYSWANTTOBUFFERTHEOUTPUTBYWRAPPINGITINABUFFEREDWRITERTRYREMOVINGTHISWRAPPINGTOSEETHEIMPACTONTHEPERFORMANCEBUFFERINGTENDSTODRAMATICALLYINCREASEPERFORMANCEOFI/OOPERATIONSTHENFORTHEFORMATTINGITSTURNEDINTOAPRINTWRITERTHEDATAFILECREATEDTHISWAYISREADABLEASANORDINARYTEXTFILEASTHELINESAREWRITTENTOTHEFILE,LINENUMBERSAREADDEDNOTETHATLINENUMBERINPUTSTREAMISNOTUSED,BECAUSEITSASILLYCLASSANDYOUDONTNEEDITASSHOWNHERE,ITSTRIVIALTOKEEPTRACKOFYOUROWNLINENUMBERSWHENTHEINPUTSTREAMISEXHAUSTED,READLINERETURNSNULLYOULLSEEANEXPLICITCLOSEFOROUT1,BECAUSEIFYOUDONTCALLCLOSEFORALLYOUROUTPUTFILES,YOUMIGHTDISCOVERTHATTHEBUFFERSDONTGETFLUSHEDSOTHEYREINCOMPLETEOUTPUTSTREAMSTHETWOPRIMARYKINDSOFOUTPUTSTREAMSARESEPARATEDBYTHEWAYTHEYWRITEDATAONEWRITESITFORHUMANCONSUMPTION,ANDTHEOTHERWRITESITTOBEREACQUIREDBYADATAINPUTSTREAMTHERANDOMACCESSFILESTANDSALONE,ALTHOUGHITSDATAFORMATISCOMPATIBLEWITHTHEDATAINPUTSTREAMANDDATAOUTPUTSTREAM5STORINGANDRECOVERINGDATAAPRINTWRITERFORMATSDATASOITSREADABLEBYAHUMANHOWEVER,TOOUTPUTDATASOTHATITCANBERECOVEREDBYANOTHERSTREAM,YOUUSEADATAOUTPUTSTREAMTOWRITETHEDATAANDADATAINPUTSTREAMTORECOVERTHEDATAOFCOURSE,THESESTREAMSCOULDBEANYTHING,BUTHEREAFILEISUSED,BUFFEREDFORBOTHREADINGANDWRITINGTHEWRITEDOUBLESTORESTHEDOUBLENUMBERTOTHESTREAMANDTHECOMPLEMENTARYREADDOUBLERECOVERSITTHEREARESIMILARMETHODSFORREADINGANDWRITINGTHEOTHERTYPESBUTFORANYOFTHEREADINGMETHODSTOWORKCORRECTLY,YOUMUSTKNOWTHEEXACTPLACEMENTOFTHEDATAITEMINTHESTREAM,SINCEITWOULDBEEQUALLYPOSSIBLETOREADTHESTOREDDOUBLEASASIMPLESEQUENCEOFBYTES,ORASACHAR,ETCSOYOUMUSTEITHERHAVEAFIXEDFORMATFORTHEDATAINTHEFILEOREXTRAINFORMATIONMUSTBESTOREDINTHEFILETHATYOUPARSETODETERMINEWHERETHEDATAISLOCATEDNOTETHATOBJECTSERIALIZATIONDESCRIBEDLATERINTHISCHAPTERMAYBEANEASIERWAYTOSTOREANDRETRIEVECOMPLEXDATASTRUCTURES6READINGANDWRITINGRANDOMACCESSFILESASPREVIOUSLYNOTED,THERANDOMACCESSFILEISALMOSTTOTALLYISOLATEDFROMTHERESTOFTHEI/OHIERARCHY,SAVEFORTHEFACTTHATITIMPLEMENTSTHEDATAINPUTANDDATAOUTPUTINTERFACESSOYOUCANNOTCOMBINEITWITHANYOFTHEASPECTSOFTHEINPUTSTREAMANDOUTPUTSTREAMSUBCLASSESEVENTHOUGHITMIGHTMAKESENSETOTREATABYTEARRAYINPUTSTREAMASARANDOMACCESSELEMENT,YOUCANUSERANDOMACCESSFILETOONLYOPENAFILEYOUMUSTASSUMEARANDOMACCESSFILEISPROPERLYBUFFEREDSINCEYOUCANNOTADDTHATTHEONEOPTIONYOUHAVEISINTHESECONDCONSTRUCTORARGUMENTYOUCANOPENARANDOMACCESSFILETOREAD“R”ORREADANDWRITE“RW”USINGARANDOMACCESSFILEISLIKEUSINGACOMBINEDDATAINPUTSTREAMANDDATAOUTPUTSTREAMBECAUSEITIMPLEMENTSTHEEQUIVALENTINTERFACESINADDITION,YOUCANSEETHATSEEKISUSEDTOMOVEABOUTINTHEFILEANDCHANGEONEOFTHEVALUESPIPEDSTREAMSTHEPIPEDINPUTSTREAM,PIPEDOUTPUTSTREAM,PIPEDREADERANDPIPEDWRITERHAVEBEENMENTIONEDONLYBRIEFLYINTHISCHAPTERTHISISNOTTOSUGGESTTHATTHEYARENTUSEFUL,BUTTHEIRVALUEISNOTAPPARENTUNTILYOUBEGINTOUNDERSTANDMULTITHREADING,SINCETHEPIPEDSTREAMSAREUSEDTOCOMMUNICATEBETWEENTHREADSTHISISCOVEREDALONGWITHANEXAMPLEINCHAPTER14THEREASONFORTHEEXCEPTIONSPECIFICATIONISTHATREADLINECANTHROWANIOEXCEPTIONNOTETHATSYSTEMINSHOULDUSUALLYBEBUFFERED,ASWITHMOSTSTREAMSREDIRECTINGSTANDARDI/OTHEJAVASYSTEMCLASSALLOWSYOUTOREDIRECTTHESTANDARDINPUT,OUTPUT,ANDERRORI/OSTREAMSUSINGSIMPLESTATICMETHODCALLSSETININPUTSTREAMSETOUTPRINTSTREAMSETERRPRINTSTREAMREDIRECTINGOUTPUTISESPECIALLYUSEFULIFYOUSUDDENLYSTARTCREATINGALARGEAMOUNTOFOUTPUTONYOURSCREENANDITSSCROLLINGPASTFASTERTHANYOUCANREADIT59REDIRECTINGINPUTISVALUABLEFORACOMMANDLINEPROGRAMINWHICHYOUWANTTOTESTAPARTICULARUSERINPUTSEQUENCEREPEATEDLYHERESASIMPLEEXAMPLETHATSHOWSTHEUSEOFTHESEMETHODS/C11REDIRECTINGJAVA/DEMONSTRATESSTANDARDI/OREDIRECTIONIMPORTJAVAIOPUBLICCLASSREDIRECTING/THROWEXCEPTIONSTOCONSOLEPUBLICSTATICVOIDMAINSTRINGARGSTHROWSIOEXCEPTIONBUFFEREDINPUTSTREAMINNEWBUFFEREDINPUTSTREAMNEWFILEINPUTSTREAM“REDIRECTINGJAVA“PRINTSTREAMOUTNEWPRINTSTREAMNEWBUFFEREDOUTPUTSTREAMNEWFILEOUTPUTSTREAM“TESTOUT“SYSTEMSETININSYSTEMSETOUTOUTSYSTEMSETERROUTBUFFEREDREADERBRNEWBUFFEREDREADERNEWINPUTSTREAMREADERSYSTEMINSTRINGSWHILESBRREADLINENULLSYSTEMOUTPRINTLNSOUTCLOSE/REMEMBERTHIS/THISPROGRAMATTACHESSTANDARDINPUTTOAFILE,ANDREDIRECTSSTANDARDOUTPUTANDSTANDARDERRORTOANOTHERFILECOMPRESSIONTHEJAVAI/OLIBRARYCONTAINSCLASSESTOSUPPORTREADINGANDWRITINGSTREAMSINACOMPRESSEDFORMATTHESEAREWRAPPEDAROUNDEXISTINGI/OCLASSESTOPROVIDECOMPRESSIONFUNCTIONALITYTHESECLASSESARENOTDERIVEDFROMTHEREADERANDWRITERCLASSES,BUTINSTEADAREPARTOFTHEINPUTSTREAMANDOUTPUTSTREAMHIERARCHIESTHISISBECAUSETHECOMPRESSIONLIBRARYWORKSWITHBYTES,NOTCHARACTERSHOWEVER,YOUMIGHTSOMETIMESBEFORCEDTOMIXTHETWOTYPESOFSTREAMSREMEMBERTHATYOUCANUSEINPUTSTREAMREADERANDOUTPUTSTREAMWRITERTOPROVIDEEASYCONVERSIONBETWEENONETYPEANDANOTHERALTHOUGHTHEREAREMANYCOMPRESSIONALGORITHMS,ZIPANDGZIPAREPOSSIBLYTHEMOSTCOMMONLYUSEDTHUSYOUCANEASILYMANIPULATEYOURCOMPRESSEDDATAWITHTHEMANYTOOLSAVAILABLEFORREADINGANDWRITINGTHESEFORMATSSIMPLECOMPRESSIONWITHGZIPTHEGZIPINTERFACEISSIMPLEANDTHUSISPROBABLYMOREAPPROPRIATEWHENYOUHAVEASINGLESTREAMOFDATATHATYOUWANTTOCOMPRESSRATHERTHANACONTAINEROFDISSIMILARPIECESOFDATAHERESANEXAMPLETHATCOMPRESSESASINGLEFILE/C11GZIPCOMPRESSJAVA/USESGZIPCOMPRESSIONTOCOMPRESSAFILE/WHOSENAMEISPASSEDONTHECOMMANDLINEIMPORTJAVAIOIMPORTJAVAUTILZIPPUBLICCLASSGZIPCOMPRESS/THROWEXCEPTIONSTOCONSOLEPUBLICSTATICVOIDMAINSTRINGARGSTHROWSIOEXCEPTIONBUFFEREDREADERINNEWBUFFEREDREADERNEWFILEREADERARGS0BUFFEREDOUTPUTSTREAMOUTNEWBUFFEREDOUTPUTSTREAMNEWGZIPOUTPUTSTREAMNEWFILEOUTPUTSTREAM“TESTGZ“SYSTEMOUTPRINTLN“WRITINGFILE“INTCWHILECINREAD1OUTWRITECINCLOSEOUTCLOSESYSTEMOUTPRINTLN“READINGFILE“BUFFEREDREADERIN2NEWBUFFEREDREADERNEWINPUTSTREAMREADERNEWGZIPINPUTSTREAMNEWFILEINPUTSTREAM“TESTGZ“STRINGSWHILESIN2READLINENULLSYSTEMOUTPRINTLNS/THEUSEOFTHECOMPRESSIONCLASSESISSTRAIGHTFORWARDYOUSIMPLYWRAPYOUROUTPUTSTREAMINAGZIPOUTPUTSTREAMORZIPOUTPUTSTREAMANDYOURINPUTSTREAMINAGZIPINPUTSTREAMORZIPINPUTSTREAMALLELSEISORDINARYI/OREADINGANDWRITINGTHISISANEXAMPLEOFMIXINGTHECHARORIENTEDSTREAMSWITHTHEBYTEORIENTEDSTREAMSINUSESTHEREADERCLASSES,WHEREASGZIPOUTPUTSTREAMSCONSTRUCTORCANACCEPTONLYANOUTPUTSTREAMOBJECT,NOTAWRITEROBJECTWHENTHEFILEISOPENED,THEGZIPINPUTSTREAMISCONVERTEDTOAREADERMULTIFILESTORAGEWITHZIPTHELIBRARYTHATSUPPORTSTHEZIPFORMATISMUCHMOREEXTENSIVEWITHITYOUCANEASILYSTOREMULTIPLEFILES,ANDTHERESEVENASEPARATECLASSTOMAKETHEPROCESSOFREADINGAZIPFILEEASYTHELIBRARYUSESTHESTANDARDZIPFORMATSOTHATITWORKSSEAMLESSLYWITHALLTHETOOLSCURRENTLYDOWNLOADABLEONTHEINTERNETTHEFOLLOWINGEXAMPLEHASTHESAMEFORMASTHEPREVIOUSEXAMPLE,BUTITHANDLESASMANYCOMMANDLINEARGUMENTSASYOUWANTINADDITION,ITSHOWSTHEUSEOFTHECHECKSUMCLASSESTOCALCULATEANDVERIFYTHECHECKSUMFORTHEFILETHEREARETWOCHECKSUMTYPESADLER32WHICHISFASTERANDCRC32WHICHISSLOWERBUTSLIGHTLYMOREACCURATE/C11ZIPCOMPRESSJAVA/USESZIPCOMPRESSIONTOCOMPRESSANY/NUMBEROFFILESGIVENONTHECOMMANDLINEIMPORTJAVAIOIMPORTJAVAUTILIMPORTJAVAUTILZIPPUBLICCLASSZIPCOMPRESS/THROWEXCEPTIONSTOCONSOLEPUBLICSTATICVOIDMAINSTRINGARGSTHROWSIOEXCEPTIONFILEOUTPUTSTREAMFNEWFILEOUTPUTSTREAM“TESTZIP“CHECKEDOUTPUTSTREAMCSUMNEWCHECKE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