spring mvc中文parti目录与翻译注记

TableofPartI目录与翻译注记(TableofcontentsPartII:文档内容(DocumentationTableofPartI目录与翻译注记(TableofcontentsPartII:文档内容(Documentation1Servlet3.0下的处理一般的SpringMVC模型2Servlet3.0下的处理一般的SpringMVC模型2弱配置Spring3弱配置Spring3SpringMVC4.2.4.RELEASE中文文本项目翻译的是SpringMVC官方4.2.4.RELEASE版本（截至16年6月23SpringMVC4.2.4.RELEASE中文文本项目翻译的是SpringMVC官方4.2.4.RELEASE版本（截至16年6月23日最新版本为4.3.0）的文档，包含原文档第21章SpringMVC部分的全部内容。本项目只为完成一份有品质的翻在文档上进行即时评论：在gitbook文档上，鼠标划过任何段落右侧，浮现号时点击即SpringMVC4.2.4.RELEASE45此较慢。翻译内容是Spring4.1.3.RELEASE版5此较慢。翻译内容是Spring4.1.3.RELEASE版部分内容，不包含SpringMVC翻译部分，不包含SpringMVC翻译。但已是1年为Spring中--目SpringWebMVC框架简介目SpringWebMVC框架简介主题themes6Servlet3.0下的MultipartResolver处理一般的SpringMVCServlet3.0下的MultipartResolver处理一般的SpringMVC配置SpringMVC7821.1SpringWebMVC框架简Spring的模型-视图21.1SpringWebMVC框架简Spring的模型-视图-控制器（MVC）框架是围绕一个DispatcherServlet来设计的，这个了@Controller和@RequestMapping的类和方法，Spring为处理器方法提供了极其多样灵活的配置。Spring3.0后的@PathVariable注解以及一些其他的特性，@Controller注解机制同时SpringWebMVCBobMartin所写的“开闭原则（TheOpen-Closed你无法增强SpringMVC中的final如AbstractController.setSynchronizeOnSession()方法等。请参考10.6.1理解AOP代理一节，其中解释了AOP代理的相关知识，论述了为什么你不能对final方法进行增强。在SpingbMVSprinSpring的视图解析也是设计得异常灵活。控制器一般负责准备一个Map模型、填充数据、返支持多种配置，包括通过文件扩展名、Accept内容头、bean、配置文件等的配置，甚至你还可以自己实现一个视图解析器ViewResolver。模型（MVC中的M，model）其实是一个Map类型的接口，彻底地把数据从视图技术中抽象分离了出来。你可以与基于模板的渲染921.1.1SpringWebMVC的新特SpringWeb21.1.1SpringWebMVC的新特SpringWebSpringWebFlowSWF意在成为web应用中的页面流(pageflow)个模块是有益的。thatguidetheuserthroughcontrollednavigationsthatdrivebusinessSpring’swebmoduleincludesmanyuniquewebsupportClearseparationofroles.Eachrole—controller,validator,commandobject,formobject,modelobject,DispatcherServlet,handlermapping,viewresolver,andsoon—canbefulfilledbyaspecializedPowerfulandstraightforwardconfigurationofbothframeworkandapplicationclassesasJavaBeans.Thisconfigurationcapabilityincludeseasyreferencingacrosscontexts,suchasfromwebcontrollerstobusinessobjectsandvalidators.Adaptability,non-intrusiveness,andflexibility.Defineanycontrollermethodsignatureyouneed,possiblyusingoneoftheparameterannotations(suchas@RequestParam,@RequestHeader,@PathVariable,andmore)foragivenReusablebusinesscode,noneedforduplication.Useexistingbusinessobjectsascommandorformobjectsinsteadofmirroringthemtoextendaparticularframeworkbaseclass.Customizablebindingandvalidation.Typemismatchesasapplication-levelvalidationerrorsthatkeeptheoffendingvalue,localizeddateandnumberbinding,andsooninsteadofString-onlyformobjectswithmanualparsingandconversiontobusinessobjects.Customizablehandlermappingandviewresolution.HandlermappingandviewresolutionstrategiesrangefromsimpleURL-basedconfiguration,tosophisticated,purpose-builtresolutionstrategies.SpringismoreflexiblethanwebMVCframeworksthatmandateaparticulartechnique.Flexiblemodeltransfer.Modeltransferwithaname/valueMapsupportsintegrationwithanyintegrationwithanyviewCustomizablelocale,timezoneandthemeresolution,supportforJSPswithorwithoutSpringtaglibrary,supportforJSTL,supportforVelocitywithouttheneedforextrabridges,andsoon.AsimpleyetpowerfulJSPtaglibraryknownastheSpringtaglibrarythatprovidessupportforfeaturessuchasdatabindingandthemes.Thecustomtagsallowformaximumflexibilityintermsofmarkupcode.Forinformationonthetaglibrarydescriptor,seetheappendixentitledChapter42,springJSPTagLibraryAJSPformtaglibrary,introducedinSpring2.0,thatmakeswritingformsinJSPpagesmucheasier.Forinformationonthetaglibrarydescriptor,seetheappendixentitledChapter43,spring-formJSPTagLibraryBeanswhoselifecycleisscopedtothecurrentHTTPrequestorHTTPSession.ThisisnotaspecificfeatureofSpringMVCitself,butratheroftheWebApplicationContextcontainer(s)thatSpringMVCuses.ThesebeanscopesaredescribedinSection6.5.4,“Request,session,andglobalsession允许其他MVC实允许其他MVC实Non-SpringMVCimplementationsarepreferableforsomeprojects.Manyteamsexpectleveragetheirexistinginvestmentinskillsandtools,forexamplewithIfyoudonotwanttouseSpring’sWebMVC,butintendtoleverageothersolutionsthatSpringoffers,youcanintegratethewebMVCframeworkofyourchoicewithSpringeasily.SimplystartupaSpringrootapplicationcontextthroughitsContextLoaderListener,andaccessitthroughitsServletContextattribute(orSpring’srespectivehelpermethod)fromwithinanyactionobject.No"plug-ins"areinvolved,sonodedicatedintegrationisnecessary.Fromtheweblayer’spointofview,yousimplyuseSpringasalibrary,withtherootapplicationcontextinstanceastheentryYourregisteredbeansandSpring’sservicescanbeatyourfingertipsevenwithoutSpring’sWebMVC.Springdoesnotcompetewithotherwebframeworksinthisscenario.ItsimplyaddressesthemanyareasthatthepurewebMVCframeworksdonot,frombeanconfigurationtodataaccessandtransactionhandling.SoyoucanenrichyourapplicationwithaSpringmiddletierand/ordataaccesstier,evenifyoujustwanttouse,forexample,thetransactionabstractionwithJDBCor21.2Spring’swebMVCframeworkis,likemanyotherweb21.2Spring’swebMVCframeworkis,likemanyotherwebMVCframeworks,request-driven,designedaroundacentralServletthatdispatchesrequeststocontrollersandoffersotherfunctionalitythatfacilitatesthedevelopmentofwebapplications.Spring’sDispatcherServlethowever,doesmorethanjustthat.ItiscompletelyintegratedwiththeSpringIoCcontainerandassuchallowsyoutouseeveryotherfeaturethatSpringMVSpringbMVCServleSprintSpingTherequestprocessingworkflowoftheSpringWebMVCDispatcherServletisillustratedinthefollowingdiagram.Thepattern-savvyreaderwillrecognizethattheDispatcherServletisanexpressionofthe"FrontController"designpattern(thisispatternthatSpringWebMVCshareswithmanyotherleadingweb下面这张图展示了SpringWebMVCTheDispatcherServletisanactualServlet(itinheritsfromtheHttpServletbaseclass),andassuchisdeclaredintheweb.xmlofyourwebapplication.YouneedtomaprequeststhatyouwanttheDispatcherServlettohandle,byusingaURLmappinginthesameweb.xmlfile.ThisisstandardJavaEEServletconfiguration;thefollowingexampleshowssuchaDispatcherServletdeclarationand（它继承自HttpServlet基类），它也是在你的TheDispatcherServletisanactualServlet(itinheritsfromtheHttpServletbaseclass),andassuchisdeclaredintheweb.xmlofyourwebapplication.YouneedtomaprequeststhatyouwanttheDispatcherServlettohandle,byusingaURLmappinginthesameweb.xmlfile.ThisisstandardJavaEEServletconfiguration;thefollowingexampleshowssuchaDispatcherServletdeclarationand（它继承自HttpServlet基类），它也是在你的配置文件下声明的。同样，你需要在web.xml望处理的请求映射到对应的URL上去。这就是标准的JavaEEServletIntheprecedingexample,allrequestsstartingwith/examplewillbehandledbyinstancenamedexample.InaServlet3.0+environment,youhavetheoptionofconfiguringtheServletcontainerprogrammatically.Belowisthebasedequivalentoftheaboveweb.xml开头的请求都会被DispatcherServlet该。在Servlet3.0+>WebApplicationInitializerisaninterfaceprovidedbySpringMVCthatensuresyourcode-basedconfigurationisdetectedandautomaticallyusedtoinitializeanyWebApplicationInitializerisaninterfaceprovidedbySpringMVCthatensuresyourcode-basedconfigurationisdetectedandautomaticallyusedtoinitializeanyServlet3container.AnabstractbaseclassimplementationofthisinterfacenamedAbstractDispatcherServletInitializermakesiteveneasiertoregistertheDispatcherServletbysimplyspecifyingitsservletmapping.SeeCode-basedServletcontainerinitializationformore现AbstractDispatcherServletInitializer，它简化了DispatcherServlet的注册工作，你只需TheaboveisonlythefirststepinsettingupSpringWebMVC.YounowneedconfigurethevariousbeansusedbytheSpringWebMVCframework(overandabovetheDispatcherServletitself).WebMVC框架使用到（除了DispatcherServlet以外的其他bean）AsdetailedinSection6.15,“AdditionalCapabilitiesoftheApplicationContext”,ApplicationContextinstancesinSpringcanbescoped.IntheWebMVCframework,eachDispatcherServlethasitsownWebApplicationContext,whichinheritsallthebeansalreadydefinedintherootWebApplicationContext.Theseinheritedbeanscanbeoverriddenintheservlet-specificscope,andyoucandefinenewscope-specificbeanslocaltoagivenServlet6.15节“AdditionalCapabilitiesoftheApplicationContext(ApplicationContext的其他作用)”中我们聊到，ApplicationContext实例是可以有范围（scope）的。在WebMVC框架中，每个DispatcherServlet都持有一个自己的上下文对象WebApplicationContextpublicclassMyWebApplicationInitializerimplementsWebApplicationInitializerpublicvoidonStartup(ServletContextcontainer)ServletRegistration.Dynamicregistration=container.addServlet("dispatcher",newDispatcherServlet());}}根WebApplicationContext对象中已经定义的所有bean。这些继承的bean可以在每个servlet的根WebApplicationContext对象中已经定义的所有bean。这些继承的bean可以在每个servlet的UponinitializationofaDispatcherServlet,SpringMVClooksforafilenamed[servlet-name]-servlet.xmlintheWEB-INFdirectoryofyourwebapplicationandcreatesthebeansdefinedthere,overridingthedefinitionsofanybeansdefinedwiththesamenameintheglobal在ConsiderthefollowingDispatcherServletServletconfiguration(intheweb.xmlWiththeaboveServletconfigurationinplace,youwillneedtoWiththeaboveServletconfigurationinplace,youwillneedtohaveafilecalled/WEB-INF/golfing-servlet.xmlinyourapplication;thisfilewillcontainallofyourSpringWebMVC-specificcomponents(beans).YoucanchangetheexactlocationofthisconfigurationfilethroughaServletinitializationparameter(seebelowfor文件，该文件必须包含所有SpringWebMVC相关的组件的定义（个ItisalsopossibletohavejustonerootcontextforsingleDispatcherServlet>ThiscanbeconfiguredbyThiscanbeconfiguredbysettinganemptycontextConfigLocationservletparameter,asshownTheWebApplicationContextisanextensionoftheplainApplicationContextthathassomeextrafeaturesnecessaryforwebapplications.ItdiffersfromanormalApplicationContextinthatitiscapableofresolvingthemes(seeSection21.9,“Usingthemes”),andthatitknowsTheWebApplicationContextisanextensionoftheplainApplicationContextthathassomeextrafeaturesnecessaryforwebapplications.ItdiffersfromanormalApplicationContextinthatitiscapableofresolvingthemes(seeSection21.9,“Usingthemes”),andthatitknowswhichServletitisassociatedwith(byhavingalinktotheServletContext).TheWebApplicationContextisboundintheServletContext,andbyusingstaticmethodsontheRequestContextUtilsclassyoucanalwayslookuptheWebApplicationContextifyouneedaccessto继承自ApplicationContext，包含了一些web个的引用来实现）。WebApplicationContext下文WebApplicationContext>TheSpringDispatcherServletusesspecialbeanstoprocessrequestsandrendertheappropriateviews.ThesebeansarepartofSpringMVC.YoucanchoosewhichspecialbeanstousebysimplyconfiguringoneormoreofthemintheWebApplicationContext.However,youdon’tneedtodothatinitiallysinceSpringMVCmaintainsalistofdefaultbeanstouseifyoudon’tconfigureany.Moreonthatinthenextsection.FirstseethetablebelowlistingthespecialbeantypestheDispatcherServletrelies在WebApplicationContext中简单地配置它们（没有忠于原文）。当然，这不是必须的，因为SpringMVC维护了一个默认的bean列表，如果你没有进行特别的配置，框架将会使用默认的bean。下一小节会介绍更多的细节，这里，我们将先快速地看一下，DispatcherServlet都依BeanMapsincomingrequeststohandlersandaBeanMapsincomingrequeststohandlersandalistofpre-andpost-processors(handlerinterceptors)basedonsomecriteriathedetailsofwhichvarybyHandlerMappingimplementation.Themostpopularimplementationsupportsannotatedcontrollersbutotherimplementationsexistsaswell.HelpstheDispatcherServlettoinvokeahandlermappedtoarequestregardlessofthehandlerisactuallyinvoked.Forexample,invokinganannotatedcontrollerrequiresresolvingvariousannotations.ThusthemainpurposeofaHandlerAdapteristoshieldtheDispatcherServletfromsuchdetails.Mapsexceptionstoviewsalsoallowingformorecomplexexceptionhandlingcode.ResolveslogicalString-basedviewnamestoactualViewtypes.LocaleResolverResolvesthelocaleaclientisusingandpossiblytheirtimezone,inordertobeabletoofferinternationalizedviews.Resolvesthemesyourwebapplicationcanuse,forexample,toofferpersonalizedlayouts.Parsesmulti-partrequestsforexampletosupportprocessingfileuploadsfromHTMLforms.Storesandretrievesthe"input"andthe"output"FlashMapthatcanbeusedtopassattributesfromonerequesttoanother,usuallyacrossa以及一系列前处理器和后处理器（hanlderinterceptors）上。具体的规则视HandlerMapping类的实现不同而有所不以及一系列前处理器和后处理器（hanlderinterceptors）上。具体的规则视HandlerMapping类的实现不同而有所不DispatcherServlet调用到负责处理某个具体请求的处因此，HandlerAdapter的主要任务就是DispatcherServlet从这些具体的细节中解放出来，交给LocaleResolver能够存储并取回负责输入输出（inputandFlashMap对象。后者可用于在请求之间传递数据，通常21.2.2默认的DispatcherServlet配Asmentionedintheprevioussection21.2.2默认的DispatcherServlet配Asmentionedintheprevioussectionforeachspecialbeanthemaintainsalistofimplementationstousebydefault.ThisinformationiskeptintheDispatcherSpertiesinthepackageorg.springframework.web.servlet正如前一个小节所描述的，DispatcherServlet维护了一个列表，其中保存了所有依赖的的一个默认实现。这份信息配置在包org.springframework.web.servlet下的DispatcherSperties中.Allspecialbeanshavesomereasonabledefaultsoftheirown.Soonerorlaterthoughyou’llneedtocustomizeoneormoreofthepropertiesthesebeansprovide.Forexampleit’squitecommontoconfigureanInternalResourceViewResolversettingsitsprefixpropertytotheparentlocationofview属性进行配置，比如说一个很常用的定制是，通过配置InternalResourceViewResolver类中的prefix属性，使其指向视图文件所在的目录。Regardlessofthedetails,theimportantconcepttounderstandhereisthatonceyouconfigureaspecialbeansuchasanInternalResourceViewResolverinyourWebApplicationContext,youeffectivelyoverridethelistofdefaultimplementationsthatwouldhavebeenusedotherwiseforthatspecialbeantype.ForexampleifyouconfigureanInternalResourceViewResolver,thedefaultlistofViewResolverimplementationsis置了InternalResourceViewResolver，那么InSection21.16,“ConfiguringSpringMVC”you’lllearnaboutotheroptionsforconfiguringSpringMVCincludingMVCJavaconfigandtheMVCXMLnamespacebothofwhichprovideasimplestartingpointandassumelittleknowledgeofhowSpringMVCworks.Regardlessofhowyouchoosetoconfigureyourapplication,theconceptsexplainedinthissectionarefundamentalshouldbeofhelpto在21.16节“SpringMVC的配置”中，你可以了解到对SpringMVC进行配置的其他方式，比如21.2.3DispatcherServlet的处理流Afteryousetup,andarequest21.2.3DispatcherServlet的处理流Afteryousetup,andarequestcomesinforthatDispatcherServlet,theDispatcherServletstartsprocessingtherequestas配置好DispatcherServlet以后，当有请求经过这个DispatcherServletTheWebApplicationContextissearchedforandboundintherequestasanattributethatthecontrollerandotherelementsintheprocesscanuse.ItisboundbydefaultunderthekeyDispatcherServlet.WEB_APPLICATION_CONTEXT_ATTRIBUTE.Thelocaleresolverisboundtotherequesttoenableelementsintheprocesstoresolvethelocaletousewhenprocessingtherequest(renderingtheview,preparingdata,andsoon).Ifyoudonotneedlocaleresolving,youdonotneedit.Thethemeresolverisboundtotherequesttoletelementssuchasviewsdeterminewhichthemetouse.Ifyoudonotusethemes,youcanignoreit.Ifyouspecifyamultipartfileresolver,therequestisinspectedformultiparts;ifmultipartsarefound,therequestiswrappedinaMultipartHttpServletRequestforfurtherprocessingbyotherelementsintheprocess.SeeSection21.10,“Spring’smultipart(fileupload)support”forfurtherinformationaboutmultiparthandling.Anappropriatehandlerissearchedfor.Ifahandlerisfound,theexecutionchainassociatedwiththehandler(preprocessors,postprocessors,andcontrollers)isexecutedinordertoprepareamodelorrendering.Ifamodelisreturned,theviewisrendered.Ifnomodelisreturned,(maybeduetoapreprocessororpostprocessorinterceptingtherequest,perhapsforsecurityreasons),noviewisrendered,becausetherequestcouldalreadyhavebeen默认以键名DispatcherServlet.WEB_APPLICATION_CONTEXT_ATTRIBUTE被绑定到请求上（ereslveult，HandlerexceptionresolversthataredeclaredintheWebApplicationContextpickupexceptionsthatarethrownduringprocessingoftherequest.UsingtheseresolversallowsyoutodefinecustombehaviorstoaddressTheSpringDispatcherServletalsosupportsthereturnofthelast-modification-date,asspecifiedbytheServletAPI.Theprocessofdeterminingthelastmodificationdateforaspecificrequestisstraightforward:theDispatcherServletlooksupanappropriatehandlermappingandtestswhetherthehandlerthatisfoundimplementstheLastModifiedinterface.Ifso,thevalueofthelonggetLastModified(request)methodoftheLastModifiedinterfaceisreturnedtothe映射表来找到请求对应的处理器，检测它是否实现了LastModified的longgetLastModified(requestYoucancustomizeindividualDispatcherServletinstancesbyaddingServletinitializationparameters(init-paramelements)totheServletdeclarationintheweb.xmlfile.Seethefollowingtableforthelistofsupported你可以在servlet的定义文件web.xml文件中添加一些servlet的初始化参数（比如param等）来定制不同的DispatcherServlet任意实现了WebApplicationContext的类。这个类会初始化该个XmlWebApplicationContext对象给contextClass所指定的context实例对象进行解析。该字符任意实现了WebApplicationContext的类。这个类会初始化该个XmlWebApplicationContext对象给contextClass所指定的context实例对象进行解析。该字符的命名空间。默认是servlet-ClassthatimplementsWebApplicationContext,whichinstantiatesthecontextusedbythisServlet.Bydefault,theXmlWebApplicationContextisused.Stringthatispassedtothecontextinstance(specifiedbycontextClass)toindicatewherecontext(s)canbefound.Thestringconsistspotentiallyofmultiplestrings(usingacommaasadelimiter)tosupportmultiplecontexts.Incaseofmultiplecontextlocationswithbeansthataredefinedtwice,thelatestlocationtakesNamespaceoftheWebApplicationContext.Defaults[servlet-name]-servlet21.3控制器(controller)的实Controllersprovideaccesstotheapplicationbehaviorthatyou21.3控制器(controller)的实Controllersprovideaccesstotheapplicationbehaviorthatyoutypicallydefinethroughaserviceinterface.Controllersinterpretuserinputandtransformitintoamodelthatisrepresentedtotheuserbytheview.Springimplementsacontrollerinaveryabstractway,whichenablesyoutocreateawidevarietyof（mdeSpring2.5introducedanannotation-basedprogrammingmodelforMVCthatusesannotationssuch,,,andsoon.ThisannotationsupportisavailableforbothServletMVCandPortletMVC.Controllersimplementedinthisstyledonothavetoextendspecificbaseclassesorimplementspecificinterfaces.Furthermore,theydonotusuallyhavedirectdependenciesonServletorPortletAPIs,althoughyoucaneasilyconfigureaccesstoServletorPortlet了@RequestMapping、@RequestParam、@ModelAttribute等注解来支持MVC的控制器实现。Availableinthespring-projectsOrgonGithub,anumberofwebapplicationsleveragetheannotationsupportdescribedinthissectionincludingMvcShowcase,MvcAjax,MvcBasic,PetClinic,PetCare,andAsyoucansee,the@Controllerand@RequestMappingannotationsallowflexiblemethodnamesandsignatures.InthisparticularexamplethemethodacceptsaAsyoucansee,the@Controllerand@RequestMappingannotationsallowflexiblemethodnamesandsignatures.InthisparticularexamplethemethodacceptsaModelandreturnsaviewnameasaString,butvariousothermethodparametersandreturnvaluescanbeusedasexplainedlaterinthissection.@Controllerand@RequestMappingandanumberofotherannotationsformthebasisfortheSpringMVCimplementation.ThissectiondocumentstheseannotationsandhowtheyaremostcommonlyusedinaServlet从上面的例子可以看到，@Controller注解和@RequestMapping注解使得方法名和方法签名的选择变得更加灵活。在上面这个例子中，方法接受一个Model类型的参数并返回一个字符串String类型的视图名，但事实上，方法可以接受的参数和返回值有更多的选择，这个我们在本小节的后面部分会提及。@Controller和@RequestMapping及其他的一些注解，共同构成publicclassHelloWorldControllerpublicStringhelloWorld(Model{model.addAttribute("message","HelloWorld!");return"helloWorld";}}21.3.1使用@Controller注解定义一个控制[Original]The@Controllerannotation21.3.1使用@Controller注解定义一个控制[Original]The@Controllerannotationindicatesthataparticularclassservestheroleofacontroller.SpringdoesnotrequireyoutoextendanycontrollerbaseclassorreferencetheServletAPI.However,youcanstillreferenceServlet-specificfeaturesifyouneed[Original]The@Controllerannotationactsasastereotypefortheannotatedclass,indicatingitsrole.Thedispatcherscanssuchannotatedclassesformappedmethodsanddetects@RequestMappingannotations(seethenext分派器（DispatcherServlet）会扫描所有注解了@Controller过@RequestMapping注解配置的方法（详见下一小节）[Original]Youcandefineannotatedcontrollerbeansexplicitly,usingastandardSpringbeandefinitioninthedispatcher’scontext.However,the@Controllerstereotypealsoallowsforautodetection,alignedwithSpringgeneralsupportfordetectingcomponentclassesintheclasspathandauto-registeringbeandefinitionsfor当然，你也可以不使用@Controller注解而显式地去定义被注解的bean，这点通过标准的Springbean的定义方式，在dispather的上下文属性下配置即可做到。但是@Controller原型[Original]Toenableautodetectionofsuchannotatedcontrollers,youaddcomponentscanningtoyourconfiguration.Usethespring-contextschemaasshowninthefollowingXML<?xmlversion="1.0"<?xmlversion="1.0"encoding="UTF-<beansxmlns="/schema/beans"<context:component-scanbase-<!--...--21.3.2使用@RequestMapping注解映射请路[Original]21.3.2使用@RequestMapping注解映射请路[Original]Youusethe@RequestMappingannotationtomapURLssuchontoanentireclassoraparticularhandlermethod.Typicallythelevelannotationmapsaspecificrequestpath(orpathpattern)ontoaformcontroller,withadditionalmethod-levelannotationsnarrowingtheprimarymappingforaspecificHTTPmethodrequestmethod("GET","POST",etc.)oranHTTPrequestparameter你可以使用@RequestMapping注解来将请求的URL（比如appointments之类的）路径映射到[Original]ThefollowingexamplefromthePetcaresampleshowsacontrollerinaMVCapplicationthatusesthis[Original]Intheexample,[Original]Intheexample,the@RequestMappingisusedinanumberofplaces.Thefirstusageisonthetype(class)level,whichindicatesthatallhandlingmethodsonthiscontrollerarerelativetothe/appointmentspath.Theget()methodhasafurther@RequestMappingrefinement:itonlyacceptsGETrequests,meaningthatanHTTPGETfor/appointmentsinvokesthismethod.Theadd()hasasimilarrefinement,andthegetNewForm()combinesthedefinitionofHTTPmethodandpathintoone,sothatGETrequestsforappointments/newarehandledbythat（类）级别的，指示了该控制器下的所有处理方法都将以/appointments开头。get(方法上publicclassAppointmentsController{privatefinalAppointmentBookpublicAppointmentsController(AppointmentBook{this.appointmentBook=}@RequestMapping(method=RequestMethod.GET)publicMap<String,Appointment>get(){return}@RequestMapping(path="/{day}",method=publicMap<String,Appointment>getForDay(@PathVariable@DateTimeFormat(iso=ISO.DATE)Dateday,Modelmodel){return}@RequestMapping(path="/new",method=RequestMethod.GET)publicAppointmentFormgetNewForm(){returnnew}@RequestMapping(method=publicStringadd(@ValidAppointmentFormappointment,BindingResult{if(result.hasErrors()){}return"redirect:/appointments";}}个请求路径为/appointments的HTTPGET请求将会最终调用到这个方法。add方法也做了类似的细化，而getNewForm(方法则同时注解了能够接受的请求的HTTP方法和路径。在这种个请求路径为/appointments的HTTPGET请求将会最终调用到这个方法。add方法也做了类似的细化，而getNewForm(方法则同时注解了能够接受的请求的HTTP方法和路径。在这种[Original]ThegetForDay()methodshowsanotherusageof@RequestMapping:templates.(Seethenext方法则展示了@RequestMapping注解的另一个作用：URI模板。（这个内容请下节[Original]A@RequestMappingontheclasslevelisnotrequired.Withoutit,allpathsaresimplyabsolute,andnotrelative.ThefollowingexamplefromthePetClinicsampleapplicationshowsamulti-actioncontrollerusing@RequestMapping[Original]TheaboveexampledoesnotspecifyGETvs.PUT,POST,andsoforth,because@RequestMappingmapsallHTTPmethodsbydefault.Use@RequestMapping(method=GET)tonarrowthe以上代码并不区分请求是GET方法还是PUT/POST或其他方法，因此@RequestMapping注解默)[Original]##@ControllerandAOPpublicclass{privatefinalClinicclinic;publicClinicController(Clinic{this.clinic=}publicvoidwelcomeHandler()}publicModelMapvetsHandler()returnnew}}[Original]InsomecasesacontrollermayneedtobedecoratedwithanAOPproxyatruntime.Oneexampleisifyouchoosetohave[Original]InsomecasesacontrollermayneedtobedecoratedwithanAOPproxyatruntime.Oneexampleisifyouchoosetohave@Transactionalannotationsdirectlyonthecontroller.Whenthisisthecase,forcontrollersspecifically,werecommendusingclass-basedproxying.Thisistypicallythedefaultchoicewithcontrollers.HoweverifacontrollermustimplementaninterfacethatisnotaSpringContextcallback(e.g.InitializingBean,*Aware,etc),youmayneedtoexplicitlyconfigureclass-basedproxying.Forexamplewith<tx:annotation-driven/>,changeto<tx:annotation-driven就是当你直接使用@Transactional注解来标注一个控制器的时候。如果——更多的时候是指控制器——但如果控制器同时必须实现另一些不支持SpringContext回调（比如InitializingBean由<tx:annotation-driven/改为tx:annotation-drivenproxy-target-class="true"/[Original]##NewSupportClassesfor@RequestMappingmethodsinSpringMVCSpringMVC3.1中新增支持@RequestMapping的[Original]Spring3.1introducedanewsetofsupportclassesfor@RequestMappingmethodscalledRequestMappingHandlerMappingandRequestMappingHandlerAdapterrespectively.TheyarerecommendedforuseandevenrequiredtotakeadvantageofnewfeaturesinSpringMVC3.1andgoingforward.ThenewsupportclassesareenabledbydefaultbytheMVCnamespaceandtheMVCJavaconfigbutmustbeconfiguredexplicitlyifusingneither.ThissectiondescribesafewimportantdifferencesbetweentheoldandthenewsupportSpring3.1中新增了一组支持@RequestMapping是RequestMappingHandlerMapping有些SpringMVC3.1之后的版本才新增的特性，这几个注解甚至是必须的。不管是通过MVC[Original]PriortoSpring3.1,typeandmethod-levelrequestmappingswereintwoseparatestages[Original]PriortoSpring3.1,typeandmethod-levelrequestmappingswereintwoseparatestages—acontrollerwasselectedfirstbyandtheactualmethodtoinvokewasnarrowedsecondby.先DefaultAnnotationHanlderMapping会先选中一个控制器，然后再通[Original]WiththenewsupportclassesinSpring3.1,RequestMappingHandlerMappingistheonlyplacewhereadecisionismadeaboutwhichmethodshouldprocesstherequest.Thinkofcontrollermethodsasacollectionofuniqueendpointswithmappingsforeachmethodderivedfromtypeandmethod-level@RequestMapping现在有了Spring3.1后引入的这组新类，RequestMappingHandlerMapping成为了这两个决策实[Original]Thisenablessomenewpossibilities.ForonceaHandlerInterceptororHandlerExceptionResolvercannowexpecttheObject-basedhandlertobe,whichallowsthemtoexaminetheexactmethod,itsparametersassociatedannotations.TheprocessingforaURLnolongerneedstobesplitdifferent的HandlerInterceptor或HandlerExceptionResolver现在可以确定拿到的这个处理器肯定是一个HandlerMethod类型，因此它能够精确地了解这个方法的所有信息，包括它的参数、应用于[Original]Therearealsoseveralthingsnolongerpossible:[Original]SelectacontrollerfirstwithaSimpleUrlHandlerMappingorBeanNameUrlHandlerMappingandthennarrowthemethodbasedon@RequestMappingannotations.[Original]Relyonmethodnamesasafall-backmechanismtodisambiguatebetweentwo@RequestMappingmethodsthatdon’thaveanexplicitpathmappingURLpathbutotherwisematchequally,e.g.byHTTPmethod.Inthenewsupportclasses@RequestMappingmethodshavetobemappeduniquely.[Original]*Haveasingledefaultmethod(withoutanexplicitpathmapping)withwhichrequestsareprocessedifnoothercontrollermethodmatchesmoreconcretely.Inthenewsupportclassesifamatchingmethodisnotfounda404erroris先通过SimpleUrlHandlerMapping或BeanNameUrlHandlerMapping来拿到负责处理请求的控制器，然后通过@RequestMapping注解配置的信息来定位