Spring Web MVC

1
Spring Web MVC
2
Ievads

• Spring ir atklata koda Java/J2EE aplikaciju
  ietvars
• Viens no interesantakiem komponentiem ir Spring
  Web MVC

3
Web aplikaciju uzdevumi

• Svarigie uzdevumi, kuri ir jaatrisina izstradajot
  web aplikaciju
• Stavoklu parvaldiba (state management)
• Darba plusma (workflow)
• Validacija
• Spring web ietvars ir uzprojektets, lai palidzet
  izstradatajiem risinat šis problemas

4
Model-View-Controller Pattern

• Model-View-Controller (MVC) ir arhitekturas
  paraugs (aprakstits 1979. gada, Smalltalk valoda)
• Pamata merkis atdalit datus (Model) no
• lietotaja interfeisa (View)
• MVC atrisina
• problemu ieviešot
• starpnieka komponenti - kontrolieri (Controller)

5
Model-View-Controller Pattern

• Model - Represents enterprise data and the
  business rules.
• View - Renders the contents of a model. Accesses
  enterprise data through the model and specifies
  how that data should be presented.
• Controller - Translates interactions
• with the view (button clicks,
• menu selections) into actions to be
• performed by the model
• (activating processes, changing
• the state of the model).

6
Spring MVC

• Spring MVC sastav no vairakiem komponentiem,
  starp kuriem notiek sadarbiba apstradajot klienta
  pieprasijumu

7
Pieprasijuma dzives cikls (1)

• Klients suta pieprasijumu, kurš tiek nodots
  DispatcherServlet komponentam
• Visi pieprasijumi vienmer tiek nodoti vienam
  servletam,
• kuru sauc par
• priekšejo kontrolieri
• (front controller)

8
Pieprasijuma dzives cikls (2)

• Komponents, kurš atbild par pieprasijuma apstradi
  ir Controller
• Lai nolemt kuram kontrolierim atdot
• pieprasijumu,
• DispatcherController
• izmanto
• HandlerMapping
• komponentus
• HandlerMapping
• URL piesaistišana kontrolieriem

9
Pieprasijuma dzives cikls (3-4)

• Kad DispatcherServlet nolemj par kontroliera
  objektu, tad parsuta tam pieprasijumu, lai
  kontrolieris izpilda biznesa logiku
• Pec darba pabeigšanas Controller atgriež
  ModelAndView
• objektu
• ModelAndView satur
• View objektu vai
• skata logisko vardu

10
Pieprasijuma dzives cikls (5)

• Ja ModelAndView objekts satur skata logisko
  vardu, tad DispatcherServlet izmanto ViewResolver
  komponenti
• ViewResolver
• atrod atbilstošu
• View objektu,
• lai attelot atbildi
• klientam

11
Pieprasijuma dzives cikls (6)

• Visbeidzot, DispatcherServlet atdod pieprasijumu
  tam View objektam, uz kuru norada ModelAndView
• View objekts ir
• atbildigs par
• pieprasijuma
• atbildes atgriešanu
• un paradišanu
• klientam

12
Spring MVC Sequence Diagram
13
Front Controller

• At the heart of Spring MVC is DispatcherServlet,
  a servlet that functions as front controller
• A front controller is a common web-application
  pattern where a single servlet delegates
  responsibility for a request to other components
  of an application to perform the actual processing

14
DispatcherServlet config

• Jakonfigure web aplikacijas web.xml faila

ltservletgt ltservlet-namegttraininglt/servlet-namegt
ltservlet-classgtorg.springframework.web.servlet.D
ispatcherServlet lt/servlet-classgt
ltload-on-startupgt1lt/load-on-startupgt lt/servletgt

• Nakamais solis ir nodefinet servlet mapping

ltservlet-mappinggt ltservlet-namegttraininglt/servlet
-namegt lturl-patterngt.htmlt/url-patterngt lt/servlet
-mappinggt
15
DispatcherServlet context

• WebApplicationContext tiek ieladets no faila
• training-servlet.xml
• kurš atrodas direktorija WEB-INF
  (lidzigi web.xml failam)
• Ir iespejams ari sadalit
• konfiguraciju starp
• vairakiem failiem

16
Vienkaršas Web lapas izveidošana

• Nepieciešamie soli, lai izveidot web lapu ar
  Spring MVC
• Uzrakstit kontroliera klasi, kas izpildis biznesa
  logiku
• Iekonfiguret kontrolieri DispatcherServlet
  konteksta konfiguracijas faila (training-servlet.x
  ml)
• Iekonfiguret view resolver, kurš piesaistis
  kontrolieri pie JSP
• Uzrakstit JSP, kas attelos lapu klientam

17
Kontroliera izveidošana
public class HomeController implements Controller
public ModelAndView handleRequest(HttpServl
etRequest request,
HttpServletResponse response) throws Exception
return new ModelAndView("home", "message",
greeting) private String greeting
public void setGreeting(String greeting)
this.greeting greeting

• Nodarbojas ar pieprasijuma apstradašanu
• Pamata metodes signatura ir lidziga servleta
  service() metodei
• Atgriež ModelAndView objektu

18
Kontroliera konfigurešana

• Kontrolieri ir jaieraksta DispatcherServlet
  konteksta konfiguracijas faila

ltbean name"/home.htm" class"com.springinacti
on.training.mvc.HomeController"gt ltproperty
name"greeting"gt ltvaluegtWelcome to Spring
Training!lt/valuegt lt/propertygt lt/beangt

• The default handler mapping is BeanNameUrlHandlerM
  apping, which uses the base name as the URL
  pattern
• When a request comes with a URL that ends with
  /home.htm, DispatcherServlet will dispatch the
  request to HomeController

19
View Resolver deklarešana

• View resolver darbs ir pec skata logiska varda
  (kurš ir atgriezts ModelAndView objekta) atrast
  pašu skatu
• Viens no variantiem ir izmantot skata vardu ka
  JSP faila vardu

ltbean id"viewResolver" class"org.springframework
.web. servlet.view.InternalResourceViewResolver"gt
ltproperty name"prefix"gt
ltvaluegt/WEB-INF/jsp/lt/valuegt lt/propertygt
ltproperty name"suffix"gt
ltvaluegt.jsplt/valuegt lt/propertygt lt/beangt
home ? /WEB-INF/jsp/home.jsp
20
JSP izveidošana

• Pedejais kas palika izveidot pašu JSP

lthtmlgt ltheadgtlttitlegtSpring Training,
Inc.lt/titlegtlt/headgt ltbodygt lth2gtmessagelt/h2gt lt/b
odygt lt/htmlgt

• Failu ir janosauc par home.jsp un ir janoliek
  zem /WEB-INF/jsp/ direktorijas

21
Kopsavilkums
22
HandlerMapping

• Tipiski piesaista specifisku kontrolieri pie URL
  adreses parauga
• Spring piedava cetras noderigas HandlerMapping
  implementacijas
• BeanNameUrlHandlerMapping
• SimpleUrlHandlerMapping
• CommonsPathMapHandlerMapping

23
BeanNameUrlHandlerMapping

• Piesaista URL adresi pie kontroliera, kurš ir
  registrets konfiguracijas faila ar tadu pašu
  vardu
• e.g. /simple.htm maps to a bean named
  /simple.htm
• Ir jaizmanto name atributu, jo / nav atlauts
  XML atributa id

ltbean class"org.springframework.web.servlet.
handler.BeanNameUrlHandlerMapping"/gt ltbean
name"/simple.htm" class"com.mvc.web.Si
mpleController"gt . . . lt/beangt
24
SimpleUrlHandlerMapping

• Pats visparigs veids ka piesaistit pieprasijuma
  URLus kontrolieriem
• Tiek konfigurets ka saraksts no name/value pariem
  (URL/kontrolieru vards)

ltbean id"simpleUrlMapping" class"org.springframe
work.web .servlet.handler.SimpleUrlHandler
Mapping"gt ltproperty name"mappings"gt ltpropsgt
ltprop key"/listCourses.htm"gtlistCoursesController
lt/propgt ltprop key"/register.htm"gtregisterStuden
tControllerlt/propgt ltprop key"/displayCourse.htm
"gtdisplayCourseControllerlt/propgt lt/propsgt
lt/propertygt lt/beangt
25
CommonsPathMapHandlerMapping

• Considers source-level metadata placed in a
  controllers source code to determine the URL
  mapping
• Need to set up build to
• include the Commons
• Attributes compiler so
• that the attributes will
• be compiled into
• application code

ltbean id"urlMapping" class"org.springframework.w
eb. servlet.handler.metadata.CommonsPathMapHandle
rMapping"/gt
/ _at__at_org.springframework.web.servlet.
handler.commonsattributes.PathMap( "/displayCours
e.htm") / public class DisplayCourseController ex
tends AbstractCommandController
26
Multiple handler mappings

• Ir iespejams deklaret vairakus handler mappings
  viena aplikacija
• Handler mapping klases implemente Springa
  Ordered interfeisu
• Var uzstadit order ipašibu, lai noradit izpildes
  kartibu attieciba uz citiem handler mapping
  komponentiem

27
Multiple handler mappings

• ltbean id"beanNameUrlMapping" class"org.springfra
  mework.web.
• servlet.handler.BeanNameUrlHandlerMapping"gt
• ltproperty name"order"gtltvaluegt1lt/valuegtlt/propert
  ygt
• lt/beangt
• ltbean id"simpleUrlMapping" class"org.springframe
  work.web.
• servlet.handler.SimpleUrlHandlerMapping"gt
• ltproperty name"order"gtltvaluegt0lt/valuegtlt/propert
  ygt
• ltproperty name"mappings"gt
• lt/propertygt
• lt/beangt

28
Kontrolieri

• Ja DispatcherServlet ir Spring MVC sirds, tad
  kontrolieri ir smadzenes

29
Kontrolieru hierarhija

• Spring piedava
• bagatu kontrolieru
• hierarhiju
• Hierarhijas virsotne
• atrodas Controller
• interfeiss
• Parasti ir jaizmanto
• kadu no
• implementacijas
• apakšklasem

30
AbstractController

• Pats vienkaršakais kontrolieris

public class SampleController extends
AbstractController public ModelAndView
handleRequestInternal( HttpServletRequest
request, HttpServletResponse response)
throws Exception return new
ModelAndView( "hello, message, "Hello
World!")
31
ModelAndView objekts

• Iekapsule skatu un modela datus, kurus skats
  attelos
• Modelis ir realizets ka java.util.Map
• Erts konstruktors viena modela objekta gadijumam
• ModelAndView(
• String viewName,
• String modelName,
• Object modelObject)

32
ModelAndView objekts

• Ir iespejams ari pievienot modelim vairakus
  objektus

public ModelAndView handleRequestInternal(
HttpServletRequest request,
HttpServletResponse response) throws Exception
ModelAndView mav new ModelAndView(welcom
e") mav.addObject("message1", Welcome!")
mav.addObject("message2", "Nice to see you!")
return mav
33
Parametru apstrade

• Web pieprasijums bieži satur vienu vai vairakus
  parametrus

ltform action"/login" method"POST"gt Login
ltinput idlogin" name"login"/gt Password
ltinput id"password" name"password"
type"password"/gt ltinput type"submit"
value"Login"/gt lt/formgt
Kada veida varetu pieklut parametriem kontroliera
koda???
34
Risinajums

• Varetu izmantot AbstractController un nolasit
  parametrus no HttpServletRequest

public ModelAndView handleRequestInternal(
HttpServletRequest request,
HttpServletResponse response) throws Exception
String login request.getParameter("login"
) String pass request.getParameter(
"password") . . .
Spring piedava ertaku iespeju!
35
AbstractCommandController

• Automatiski ieraksta parametrus specialaja
  komandas objekta (command object)
• Ir iespeja pievienot validatoru, lai nodrošinat
  to, ka parametri ir pareizi
• Galvena izpildes metode
• handle(
• HttpServletRequest request,
• HttpServletResponse response,
• Object command,
• BindException errors)

36
AbstractCommandController

• public class DisplayCourseController extends
  AbstractCommandController
• public DisplayCourseController()
• setCommandClass(DisplayCourseCommand.class)
• protected ModelAndView handle(HttpServletRequest
  request,
• HttpServletResponse response, Object command,
• BindException errors) throws Exception
• DisplayCourseCommand displayCommand
• (DisplayCourseCommand) command
• Course course courseService.getCourse(displ
  ayCommand.getId())
• return new ModelAndView("courseDetail",
  "course", course)

37
Command Object

• A command object is a bean that is meant to hold
  request parameters for easy access

public class DisplayCourseCommand private
Integer id public void setId(Integer id)
this.id id public Integer getId()
return id

• Spring will attempt to match any parameters
  passed in the request to properties in the
  command object

38
Parskats
39
Formu apstrade

• Tipiska web aplikacija satur vismaz vienu formu
• Lietotajs aizpilda formu un aizsuta to
• Dati tiek nosutiti serverim
• Kad datu apstrade ir pabeigta, tad lietotajs
  sanem vienu no variantiem
• Lapa ar veiksmigas izpildes pazinojumu
• Formas lapa ar kludu pazinojumiem

Kada veida varetu to realizet???
40
Risinajums

• Izmantot AbstractController formas attelošanai
• Izmantot AbstractCommandController formas
  apstradei
• Trukums vajag uzturet divus dažadus
  kontrolierus, kuri kopa nodarbojas ar viena
  uzdevuma risinašanu

41
SimpleFormController

• Formu kontroliera funkcionalitate
• Attelo formu uz HTTP GET pieprasijuma
• Apstrada formu uz HTTP POST pieprasijuma
• Ja notiek kluda, tad atkartoti parada formu

public class RegisterStudentController extends
SimpleFormController public RegisterStudentCont
roller() setCommandClass(Student.class) p
rotected void doSubmitAction(Object
command) throws Exception Student student
(Student) command studentService.enrollStudent(
student)
42
SimpleFormController config

• Kontrolieris ir uzprojektets tada veida, lai pec
  iespejas vairak atdalit skatu detalas no
  kontroliera koda

ltbean id"registerStudentController"
class"com.springinaction. training.mvc.Registe
rStudentController"gt ltproperty
name"formView"gt ltvaluegtnewStudentFormlt/valuegt
lt/propertygt ltproperty name"successView"gt ltvalu
egtstudentWelcomelt/valuegt lt/propertygt . .
. lt/beangt
HTTP GET

• Ja ir nepieciešams aizsutit datus skatam, tad
  vajag izmantot onSubmit() metodi

43
Formu validacija

• Viens no svarigiem uzdevumiem ir formas datu
  validacija
• Par validaciju atbild sekojošais interfeiss

public interface Validator void
validate(Object obj, Errors errors) boolean
supports(Class clazz)

• Implementejot ši interfeisa validate() metodi
  vajag parbaudit objekta atributu vertibas un
  noraidit nepareizas vertibas izmantojot Errors
  objektu

44
Validatora registrešana

• Validatoru vajag piesaistit kontrolierim
  konfiguracijas faila

ltbean id"registerStudentController"
class"com.springinaction.training.mvc.
RegisterStudentController"gt ltproperty
name"validator"gt ltbean class"com.springinac
tion.training. mvc.StudentValidator"/gt
lt/propertygt lt/beangt
45
Wizard (daudzekranu) formas

• Uzdevums realizet aptaujas formu ar 40
  jautajumiem

Kada veida varetu to realizet???

• Variants izmantot SimpleFormController,
  izvietot visus jautajumus viena lapa
• Bet tas nav erti lietotajam!

46
Wizard formas

• Spring piedava kontrolieri, kas atbild par secigu
  virzišanos cauri vairakam lapam
• AbstractWizardFormController
• Lidzigs parastai formai, bet ir iespejams validet
  datus pa dalam (katra ekrana savu dalu)
• Formas apstrade parasti notek pašas beigas
• Ir iespeja visu procesu atcelt (cancel) jebkura
  bridi

47
Wizard formas kontrolieris

• public class FeedbackWizardController
• extends AbstractWizardFormController
• public FeedbackWizardController()
• setCommandClass(FeedbackSurvey.class)
• protected ModelAndView processFinish(
• HttpServletRequest request,
• HttpServletResponse response, Object command,
• BindException errors) throws Exception
• FeedbackSurvey feedback (FeedbackSurvey)
  command
• feedbackService.submitFeedback(feedback)
• return new ModelAndView("thankyou")

48
Wizard formas konfigurešana

• Formas kontroliera konfigurešana

ltbean id"feedbackController" class"com.springina
ction. training.mvc.MyWizardController"gt ltprope
rty name"pages"gt ltlistgt
ltvaluegtgenerallt/valuegt ltvaluegtinstructorlt/
valuegt ltvaluegtcourselt/valuegt
lt/listgt lt/propertygt lt/beangt

• Šeit tiek definetas visas lapas

49
Wizard formas lapas

• Pa lapam var parvietoties ierakstot pieprasijuma
  parametru ar vardu "_targetX", kur X ir lapas
  numurs

ltform method"POST" action"feedback.htm"gt ltinpu
t type"submit" value"Back" name"_target1"gt
ltinput type"submit" value"Next"
name"_target3"gt lt/formgt
50
Wizard formas finish/cancel

• Formas pabeigšana - tiks izsaukta metode
  processFinish()

ltinput type"submit" value"Finish"
name"_finish"gt

• Formas atcelšana - tiks izsaukta metode
  processCancel()

ltinput type"submit" value"Cancel"
name"_cancel"gt
51
Wizard formas validacija

• Formas komandas objekts tiek validets pa lapam

protected void validatePage( Object command,
Errors errors, int page) FeedbackSurvey
feedback (FeedbackSurvey) command FeedbackValid
ator validator (FeedbackValidator)
getValidator() if(page 0)
validator.validateEmail(feedback.getEmail(),
errors)
52
Vairaku darbibu apstrade

• Visi lidz šim apskatitie kontrolieri pildija kadu
  vienu uzdevumu
• Veidot vairakus kontrolierus lai pildit lidzigus
  uzdevumus nav isti racionali
• Piemeram, vajag attelot kursu sarakstu dažados
  variantos
• Nesakartota veida
• Sakartoti pec datuma
• Sakartoti pec nosaukuma

Kada veida varetu to realizet???
53
MultiActionController

• public class ListCoursesController
• extends MultiActionController
• public ModelAndView coursesUnsorted(
• HttpServletRequest request, HttpServletResponse
  response)
• . . .
• public ModelAndView coursesSortedByStartDate(
• HttpServletRequest request, HttpServletResponse
  response)
• . . .
• public ModelAndView coursesSortedByName(
• HttpServletRequest request, HttpServletResponse
  response)
• . . .

54
Metodes varda noteikšana

• Pec noklusejuma metodes vards tiek noteikts
  izmantojot URL sastavdalu
• http///coursesUnsorted.htm ?
  coursesUnsorted()
• http///coursesSortedByStartDate.htm ?
  coursesSortedByStartDate()
• http///coursesSortedByName.htm ?
  coursesSortedByName()

55
Metodes varda noteikšana

• Ir pieejami ari citi varianti
• ParameterMethodNameResolver - Resolves the
  execution method name based on a parameter in the
  request
• PropertiesMethodNameResolver -Resolves the name
  of the execution method by consulting a list of
  key/value pairs

56
Parskats
57
ThrowawayController

• Nav Controller hierarhijas dala
• Netiek izmantots HTTP pieprasijums vai komandas
  objekts
• Parametri tiek ierakstiti tieši kontrolieri
• Ir noderigi, kad nav modela objekta, kuru varetu
  izmantot
• Atškiriba no citiem kontrolieriem, nav singleton

public interface ThrowawayController
ModelAndView execute() throws Exception
58
ThrowawayController

• public class DisplayCourseController
• implements ThrowawayController
• private Integer id
• public void setId(Integer id) this.id id
• public ModelAndView execute() throws Exception
  
• Course course courseService.getCourse(id)
• return new ModelAndView(
• "courseDetail", "course", course)

59
Interceptors

• Iespeja pievienot papildus funkcionalitati pirms
  un pec pieprasijuma
• Satur divas interception metodes
• preHandle un postHandle
• Satur vienu callback metodi
• afterCompletion
• Tiek piesaistits kontrolieru kopai kopa ar
  HandlerMapping

60
Piemers Interceptor config

• ltbeansgt
• ltbean id"handlerMapping" class"org.springfra
  mework.web.
• servlet.handler.SimpleUrlHandlerMapping"gt
• ltproperty name"interceptors"gt
• ltlistgt
• ltref bean"officeHoursInterceptor"
  /gt
• lt/listgt
• lt/propertygt
• ltproperty name"mappings"gt
• ltvaluegt
• /.formeditAccountFormController
• lt/valuegt
• lt/propertygt
• lt/beangt
• ltbean id"officeHoursInterceptor"
• class"samples.TimeBasedAccessIntercepto
  r"gt
• ltproperty name"openingTime" value"9"/gt
• ltproperty name"closingTime" value"18"/gt

61
Piemers Interceptor kods

• public class TimeBasedAccessInterceptor extends
  HandlerInterceptorAdapter
• . . .
• public boolean preHandle(HttpServletRequest
  request,
• HttpServletResponse response,
• Object handler) throws Exception
• Calendar cal Calendar.getInstance()
• int hour cal.get(HOUR_OF_DAY)
• if (openingTime lt hour lt closingTime)
• return true
• else
• response.sendRedirect(
• "http//host.com/outsideOfficeHours.html")
• return false

62
View Resolving

• A view is a bean that renders results to the user
• Spring MVC consults view resolvers when trying to
  determine which View bean to use

63
ViewResolver implementacijas

• Spring piedava cetras pamata ViewResolver
  interfeisa implementacijas
• InternalResourceViewResolver
• Resolves logical view names into View objects
  that are rendered using template file resources
  (such as JSPs and Velocity templates)
• BeanNameViewResolver -
• Resolves logical view names into View beans in
  the DispatcherServlets application context

64
ViewResolver implementacijas

• ResourceBundleViewResolver
• Mappings are contained within a properties file
• Supports internationalization
• XmlViewResolver
• Mappings are contained within a XML file that is
  separate from the DispatcherServlets application
  context
• VelocityViewResolver
• FreeMarkerViewResolver

65
View klases

• Spring piedava sekojošas skatu apakšklases
• JstlView
• Attelo viewName par JSP lapu, kura uzstaditi ari
  JSTL tagu bibliotekam vajadzigie mainigie,
  piemeram, lokalizacija.
• RedirectView
• Veic HTTP Redirect
• VelocityLayoutView, VelocityToolboxView,
  VelocityView
• Velocity skati ar vai bez papildu objektiem, ko
  konfigure toolbox.xml
• FreeMarkerView

66
Internacionalizacija

• Spring dod iespeju automatiski izveleties
  zinojumu tekstus izmantojot lietotaja lokali
• DispatcherServlet izmanto LocaleResolver lai
  noteikt klienta lokali
• AcceptHeaderLocaleResolver
• izmantot HTTP "Accept-language" hederi lokales
  atrašanai
• CookieLocaleResolver
• izmantot cookies lokales atrašanai
• SessionLocaleResolver
• lokale liek glabata sesija

67
Internacionalizacija

• Lokales izmainas funkcionalitatei var izmantot
  klasi LocaleChangeInterceptor, to ir japieliek
  klat kadam HandlerMapping
• Visbeidzot, teksta zinojumus ir jaieraksta failos
  zem /WEB-INF/classes/
• messages_en.properties
• messages_de.properties
• utml
• JSP lapa zinojumus var ielikt izmantojot tagu
• ltfmfmessage key"ltmsg_namegt"gt
• ltfmfmessage keyhello"gt

msg_namemsg_text greetingsHello! trueYes false
No
68
Springa temas

• Viegli konfigurejamas un izpildes laika
  nomainamas aplikacijas "adas

69
Springa temas

• Tema (theme) ir statisko resursu kolekcija, kas
  ietekme aplikacijas vizualo stilu
• style sheets (css), images
• ResourceBundleThemeSource ielade properties
  failus no classpath saknes
• /WEB-INF/classes/
• Daudz lidzibas ar internacionalizacijas
  konfigurešanu

70
Springa temas

• Properties faila piemers

styleSheet/themes/cool/style.css
background/themes/cool/img/coolBg.jpg

• JSP lapa ir jaizmanto ltspringthemegt tagu

lt_at_ taglib prefix"spring" uri"http//www.sprin
gframework.org/tags"gt lthtmlgt ltheadgt
ltlink rel"stylesheet" href"ltspringtheme
code"styleSheet"/gt" type"text/css"/gt
lt/headgt ltbody background"ltspringtheme
code"background"/gt"gt ... lt/bodygt lt/htmlgt
71
Failu augšupielade

• Spring piedava failu augšupielades
  funkcionalitati (multipart file upload)
• Atbalsta CommonFileUpload un COS FileUpload

lth1gtPlease upload a filelt/h1gt ltform method"post"
action"upload.form" enctype"multipart/form-dat
a"gt ltinput type"file" name"file"/gt ltinput
type"submit"/gt lt/formgt
ltbean id"multipartResolver class"org.springfram
ework. web.multipart.commons.CommonsMultipartRes
olver"gt ltproperty name"maxUploadSize"
value"100000"/gt lt/beangt
72
Iznemumu apstrade

• Viena no Springa ipatnibam - vairums iznemumu ir
  RuntimeException apakštipi, tos nevajag metodes
  kert vai deklaret
• Ir piedavata iespeja apstradat negaiditas kludas
• SimpleMappingExceptionResolver
• Iespeja piesaistit skatu iznemuma klasei
  konfiguracijas faila
• HandlerExceptionResolver
• Interfeiss, kuru vajag implementet, lai apstradat
  kontrolieru kludas

73
SimpleMappingExceptionResolver

• ltbean id"exceptionResolver" class"org.springfra
  mework.web.
• servlet.handler.
• SimpleMappingExceptionResolver"gt
• ltproperty name"exceptionMappings"gt
• ltpropsgt
• ltprop key"java.lang.Exception"gt
• friendlyError
• lt/propgt
• lt/propsgt
• lt/propertygt
• lt/beangt

74
Countries piemers

• Spring piemeru, kuru var palaist un apskatities
  kodu var atrast zem
• \spring-framework-2.0.6\samples\countries\
• Special Spring MVC features

• paged list navigation
• locale and theme switching
• localized view definitions
• page composition through
• view definitions
• generation of PDF and
• Excel views

75
Resursi

• Spring Home
• http//www.springframework.org
• C. Walls, R.Breidenbach. Spring in Action
  http//www.manning.com/walls2/
• Spring Web MVC Framework http//www.springframewor
  k.org/docs/reference/mvc.html
• Spring MVC step-by-step Tutorial
• http//www.springframework.org/docs/MVC-step-by-s
  tep/Spring-MVC-step-by-step.html

76
Resursi

• Model-View-Controller pattern by Sun
  http//java.sun.com/blueprints/patterns/MVC.html
• Core J2EE Patterns - Front Controller
  http//java.sun.com/blueprints/corej2eepatterns/Pa
  tterns/FrontController.html