Struts Tutorial Passo A Passo 阳飞.docx

Struts Tutorial Passo A Passo 阳飞.docx

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StrutsTutorialPassoAPasso阳飞

StrutsTutorial

Authors:

StephanWiesner（stephan@stephanwiesner.de）

Version:

1.03

MajorchangeoftheunderlyingXMLstructure（footnotes,glossary,directoryoflistings,etc）

ChapteraboutTemplates.

UsingANTforcreationofWARfiles.

（English）

Published:

14.04.2002

Abstract

ThisisatutorialfortheStrutsframework.Itconsistsofasmallapplicationwhichisdevelopedstepbystep.Bookscanbedisplayedinthebrowser,newbookscanbecreatedandtheirstatesaved/loadedinxmlfiles.Itrytodothewholethingstepbystep,withlotsofscreenshotstoshowthatitreallydoesworkandtohelpyoualong.Manyofthescreenshotsactuallyshowerrormessages.Thiswillhelpyouavoidsomeofthemanypitfallsalongtheway.ThisworkshouldenableyoutoworkwithStrutsinashorttime,butyouwillnotbecomeaStrutsguruwithit.So,youshouldhavetheofficialdocumentationathandtoreadthetheoreticalbackground.

Contents:

I.Introduction

II.InstallationofStruts

III.TheFirstTry:

SimpleJSP

IV.SecondTry:

StrutsForInternationalization

V.StrutsforForms

VI.Struts:

IntroducingtheActionForm

VII.AbetterwaytoseparateBookandBookForm

VIII.HandlingInvalidEntries

IX.Recapitulation:

Whereweare

X.UsingLogic

XI.Templates

XII.FAQ

XIII.BeanstoXML

XIV.ReplacingJSPwithXSLT

XV.IntroducingAspectJ

XVI.AntforCompilationandDistribution

XVII.Conclusions

XVIII.Epilogue:

TechnicalBackgroundaboutthisDocument

XIX.AbouttheAuthor

1.Introduction

WhyIwrotethetutorial,whoisthetargetgroupandanoverviewofthecontents.

Goals:

Togetanideawhatthistutorialisaboutandwhetheryoushouldbeabletolearnsomethingnew.

DuringthistutorialIwilldevelopalittleapplication,stepbystep,thatimplementsApacheStruts.

YoushouldhavesomeexperiencewithJavaServerpages,JSPandXML.Furtheryoushouldhaveaserverimplementedthatcanrunthosethings.Seemyhomepageforatutorialaboutthat,ifnot.

ThetutorialwillstartwiththeinstallationoftheStrutsframeworkitself,willimplementsomeminimalisticfeaturesinpureHTMLandwillthenaddsomeStrutsfuntionality,givinghintsandthoughtsabouthowtoorganizeyourcode.FinallyI'llevenshowyousometrickswithAspectJtomakeyourlifeasaprogrammersomewhateasier.

Thistutorialisunderconstantdevelopment,socheckbackfromtimetotime.Alsotakealookatthechapterabouttechnicalbackgrounds.Itmightinterestyou.

2.InstallationofStruts

Thisoneisquiteeasy.Itakeit,youhavearunningTomcat3.2（orcomparableserver）andknowhowtohandleit?

Illustration1:

Thefolderstructure

1.Generateadirectorystructurelikeinthescreenshot（adaptifyoudon'tuseTomcat）

2.Downloadthenewest（binary）versionofStruts（IUse1.0.2）[I].

3.Extractthedownload.

4.CopytheStruts.jar

5.Pasteittothelibdirectoryofyourapplication（seeabove）.DON'T,IrepeatDON'TjustaddittoyourCLASSPATH!

Ididthatanditworkedfine.UntilIrestartettheTomcat,thatis.Tookmequiteawhiletofiguretheconnectionout.Atleastwithmysystemtherewasabigproblem,soIrecommendtoadditjusttothisapplication.

6.Thatisall,forthemoment.Don'tdeletetherestoftheStrutsdownload,though.Wewillneedmorelateron.

3.TheFirstTry:

SimpleJSP

WewillstartwithasimpleJSPpage,justtoensurethatwedideverythingrightuntilnow.CreateafilecalledBookView.jspinthe'strutsShop'-directory.

FirstJSP

<%@pagelanguage="java"%>

BookView

html>

Illustration2:

OurFirstPage

Notveryimpressive,Iadmit,butwewillstartimprovingitrightaway.

4.SecondTry:

StrutsForInternationalisation

WewilluseStrutstodisplaypredefinedtextsinthedefaultlanguageoftheuser.Well,notforeveryuser,Isuppose...ThiswillrequiresomecloserlookatthefunctionalityofStruts.

Goals:

Displaythetitleofthepageindifferentlanguages.

WestartswithsomebasicsaboutStruts:

GotothedirectoryyouextractedtheStrutsdownloadtoandcopysomefilestoourWEB-INFdirectorylikeinthescreenshot（youshouldbrowsethroughafewoftheexamplesthatcomewithStruts,whilesearchingforthem）.

Illustration3:

NeededLTDfiles

Takethetimetolookintothestruts-html.tldfile.Don'tpanic,though,wewillnotadaptthosefiles!

TheyaretheretohelpusanddefinethefunctionalityofStruts.YoucanfindtheparametersyouneedforusingaStruttaginthere.Youcouldlookintotheofficialdocuandwouldprobablybebetteroff,though.

Ourweb.xmlmustdefineanactionServletandthelinkstotheltd-files.Justcopyoneweb.xmlfromtheStrutssourcesandremoveeverythingelse.

EmptyStruts-config.xml

xmlversion="1.0"encoding="ISO-8859-1"?

>

DOCTYPEstruts-configPUBLIC

"-//ApacheSoftwareFoundation//DTDStrutsConfiguration1.0//EN"

"http:

//jakarta.apache.org/struts/dtds/struts-config_1_0.dtd">

web.xml

xmlversion="1.0"encoding="ISO-8859-1"?

>

DOCTYPEweb-app

PUBLIC"-//SunMicrosystems,Inc.//DTDWebApplication2.2//EN"

"

action

org.apache.struts.action.ActionServlet

application

ApplicationResources

config

/WEB-INF/struts-config.xml

debug

2

detail

2

validate

true

2

--StandardActionServletMapping-->

action

*.do

--TheWelcomeFileList-->

index.jsp

index.html

--StrutsTagLibraryDescriptor-->

/WEB-INF/struts-bean.tld

/WEB-INF/struts-bean.tld

/WEB-INF/struts-html.tld

/WEB-INF/struts-html.tld

/WEB-INF/struts-logic.tld

/WEB-INF/struts-logic.tld

/WEB-INF/struts-template.tld

/WEB-INF/struts-template.tld

Okay,letsstartwithsomethingreallyeasy.Wewilldisplaythetitleofthepageindifferentlanguages,dependingonthepreferenceoftheuser.

Createafilecalled'ApplicationResources.properties'intheclassesdirctory.

Openitandentertheline:

'index.title=StrutsTutorial'intoit

Createanotherfilecalled'ApplicationResources_de.properties'（deforDeutschland（germany））andenter'index.title=StrutsEinführung'

EdittheBookView.jspandchangetheheadto:

BookView.jsp:

IntroducingInternationalization

<%@pagelanguage="java"%>

<%@tagliburi="/WEB-INF/struts-bean.tld"prefix="bean"%>

<%@tagliburi="/WEB-INF/struts-html.tld"prefix="html"%>

<%@tagliburi="/WEB-INF/struts-logic.tld"prefix="logic"%>

htmllocale="true">

base/>

Illustration4:

Displayingthegermantitleelement

NowyouhavetorestartyourTomcatandafterreloadingthepageyoushouldseeatitle.Whatexactlyyouseedependsonthedefaultlanguageonyourcoumputer.Iseethegermantitle'StrutsEinführung'.Changeyourdefaultlanguageandrelaodthepage.Setitfirsttoenglish,thentogermanandthetitleshouldadaptaccordingly.

Note:

Asyoujustsawitisveryeasytodisplaytextsindifferentlanguages.Whatyouwillrealizeveryquickly,though,ishowtediousitcangettoenter/check/changeeverythingindifferentlanguages,butthathasnothingtodowiththewayitisimplementedinStruts.IhavemadetheexperiencethatitisamusttoimplementeveryTextusingthevariablesandthatitisbesttousejustonefileforthedevelopment.then,beforemakingarelease,Iadaptthefilesfortheotherlanguages.ThiswayIsavealotoftime.Don'tthinkyoucanwriteplaintextandexchangeitforvariablesatreleasetimethough!

5.StrutsforForms

Thischapterwillfinallyallowustodosomerealprogramming（abouttime,Iknow）.WewillcreateasimpleBean（Book.java）andtwoJSPpages.Onetocreateanewbookandasecondtodisplayit.ForthatwewilluseStruts.Further,wewilltakeafirstlookatthestruts-config.xmltoconfigureourapplication.

Goals:

TounderstandhowStrutscanhelpuswithstandardbehaviourconcerningforms.

Let'sstartwiththeBean.CreateafileBook.java[II]inyourclassesdirectoryandenterthefollowing:

Book.java

importjava.util.Vector;

/*

Asimplebook.

@authorstephan@stephanwiesner.de

*/

publicclassBook

{

/**Thetitle*/

privateStringtitle="";

/**Wecanhavemorethanoneauthor*/

privateVectorauthors=newVector（）;

/**Thenumberofpagesthebookhas*/

privateintpages=0;

/**Standardconstructor.*/

publicBook（）

{}

/**@paramtitleThenewTitle*/

publicvoidsetTitle（Stringtitle）

{this.title=t