Addison wesley JSP and XML integrating XML and web services in your JSP application mar 2002 ISBN 0672323540

JSP™andXMLIntegratingXMLandWeb
ServicesinYourJSP™Application
ByCaseyKochmer,EricaFrandsen


Publisher :AddisonWesley
PubDate :March19,2002
ISBN :0-672-32354-0
Pages :592



ThefirstInternetrevolutionwasallaboutdelivering
informationtopeople.Wearenowinthesecond
revolution,whichfocusesondeliveringinformationto
systems.XMListhetoolthatmakesthisnewrevolutiona

reality,andWebservicesarethemethodsbywhich
Tableof businesseswilldrivesystem-to-systemcommunication.
•
Contents JSP(TM)andXMLtakesyoubeyondthebasics,giving
youpracticaladviceandin-depthcoverage.Inthebook,
• Index
you'lllearnthetechnologiesandtechniquesneededto
createyourownWebservicesforuseinJSPapplications.
Writtenbyprogrammersforprogrammers,thebookwill
helpyousuccessfullyutilizetheseexcitingtechnologies
withminimalhassleandmaximumspeed.

777

Copyright



AbouttheAuthors



Acknowledgments



Introduction



OnXML



OnWebServices



OntheStructureoftheBook



AWordaboutSourceCode

HowtoUsetheBook



ConventionsUsedinThisBook



AFinalNote





PartI.Data,XML,andWebServicesIntroduction
Chapter1.IntegratingJSPandData




UsingJSPwithaDatabase



OtherConsiderations

BasicDesignConcepts



Summary




Chapter2.IntroductiontoXML/XSL



WhatIsXML?



RulesofXML



OntoUsingXML



XSL

Summary




Chapter3.UnderstandingWebServices



WhatIsaWebService?



CrystalBallReadings



TheABCsofWebServices



HowtoUseaWebService



Summary

PartII.IntegratingJSPandXML
Chapter4.AQuickStarttoJSPandXMLTogether



TheRelationshipBetweenXMLandJSP



JavaXML/XSLAPIs



Summary




Chapter5.UsingDOM



WhatIstheDOM?



NodesandTreeStructure

ProgrammingwithDOM



JDOM,dom4j,andDeferredDOM



Summary




Chapter6.ProgrammingSAX



WhatIsSAX?



TheWorkingsofSAX



Summary

Chapter7.SuccessfullyUsingJSPandXMLinanApplication



UsingaJavaRepresentationofanXMLDocument



WhyNotJustUseSAXorDOM?



InstallingJDOManddom4j



WhyBothJDOManddom4j?



CommonWaystoUseXML



UsingaDatabasewithXML

PullinginXMLFiles



Summary




Chapter8.IntegratingJSPandWebServices



ThinkinginJSPandWebServices



IntegratingaWebServiceintoaJSPPage



WhenShouldYouBuildYourOwnWebService?



BuildingaCorporateWebService

ApacheSOAPHelp



Summary




Chapter9.AdvancedJSPandXMLTechniques



AccessingWebServicesfromaBrowser



HandlingLargeXMLDocuments



HandlingSpecialCharactersandEncoding



UsingXMLTagLibraries

Summary






PartIII.BuildingJSPSitestoUseXML
Chapter10.UsingXSL/JSPinWebSiteDesign



HandlingXMLFilesDirectly



BuildinganXMLServletHandler



Summary





Chapter11.UsingXMLinReportingSystems
ArchitectureofReportingSystems

WhentoUseXMLwithReports



DataSourceforReports



ResultSettoXML



BringingItAllTogether



TheSortingTableStylesheet



TheCrossTabStylesheet



Summary

Chapter12.AdvancedXMLinReportingSystems



Multiple-PageReports



ReportsonDatawithOne-to-ManyRelationships



Real-WorldReportingSystems



Well-FormedDocumentsRevisited



Summary




Chapter13.BrowserConsiderationswithXML

Client-SideXMLandBrowserSupport



Client-SideJavaScriptandXML



Client-SideTransformationsandXML



Summary




Chapter14.BuildingaWebService



DesigningaWebService



BuildingtheWebService



CreatingaWSDLFile

RegisteringWithinUDDI



UsingJavatoAccessaWSDLDocument



Summary




Chapter15.AdvancedApplicationDesign



DynamicJSP



SOAPServerSecurityConcerns



QuickTakes

Summary








PartIV.Appendixes

AppendixA.SettingUp



InstallingtheJSPEnvironment



NetBeans



TheMySQLDatabaseServer



Summary

AppendixB.IntroductiontoJSPandHowThingsWork



JSPBasics



JSPActions,Directives,andImplicitObjects



AMoreRobustJSPExample



AdditionalInformationAboutJSP



Summary




AppendixC.TagLibrary

TagLibraryOverview



WhatIsaTagLibrary?



TheSixStepstoBuildingTagLibraries



TagLibraryConcepts



BuildingaTagLibrary



GeneralNotes



Summary

AppendixD.XSLReference



XSLTandXPath



Reference





Index


Copyright
Manyofthedesignationsusedbymanufacturersandsellerstodistinguishtheir
productsareclaimedastrademarks.Wherethosedesignationsappearinthis
book,andAddison-Wesleywereawareofatrademarkclaim,thedesignations
havebeenprintedininitialcapitallettersorinallcapitals.
Theauthorandpublisherhavetakencareinthepreparationofthisbook,but
makenoexpressedorimpliedwarrantyofanykindandassumenoresponsibility
forerrorsoromissions.Noliabilityisassumedforincidentalorconsequential
damagesinconnectionwithorarisingoutoftheuseoftheinformationor
programscontainedherein.
Thepublisheroffersdiscountsonthisbookwhenorderedinquantityforspecial

sales.
Formoreinformation,pleasecontact:
PearsonEducationCorporateSalesDivision
201W.103rdStreet
Indianapolis,IN46290
(800)428-5331

VisitAWontheWeb:www.awl.com/cseng/
Copyright©2002byPearsonEducation
Allrightsreserved.Nopartofthispublicationmaybereproduced,storedina
retrievalsystem,ortransmitted,inanyformorbyanymeans,electronic,
mechanical,photocopying,recording,orotherwise,withoutthepriorconsentof
thepublisher.PrintedintheUnitedStatesofAmerica.Publishedsimultaneously
inCanada.


050403024321
FirstPrinting:March2002

Credits
ExecutiveEditor
RochelleJ.Kronzek
AcquisitionsEditor
MichelleNewcomb
DevelopmentEditor
MarkRay
ManagingEditor
MattPurcell
ProjectEditor
ChristinaSmith

ProductionEditors
SethKerney
RhondaTinch-Mize
MattWynalda
Indexer
MandieFrank
Proofreader


SuzanneThomas
TechnicalEditor
CraigPfeifer
TeamCoordinator
PamaleeNelson
InteriorDesigner
GaryAdair
CoverDesigner
AlanClements
PageLayout
RebeccaHarmon
MichelleMitchell

Dedications
Writingthisbookwasalongprocess.Asinallchoices,thisprojecthadits
rewardsanditsconsequences.Intheend,themostimportantlessonIlearned
wasoneoflife,notJSP.Icansharemythoughtsinthispoem.Idedicatethe
booktoanyonewhotakesamomenttoreadmypoetry.
DaysofWonderHeavenandHellarenotafterlifeHeavenandHellarepartof
lifeIt'sinlifewemakeourjoyIt'sinlifewebuildourwallsToanyonewho
readsthismayyoufindyourownheavenmayyoufindyourownpoemsBreak

freeofyourchainsJumpyourwallsLivelifeasifinheavenanddon'tmakelife
hellWehaveonlyonelifetoreliveoveragainininfinityDon'tregretasyou
moveforwardSincethepastisonlyformemoriesThesecrettolifeissimplyto
betruetoyourselfandsmilethenyouwillbeabletolookuponeachnewday


withthewonderitdeservesIt'sallanyonecaneverdo—CaseyKochmer
Idedicatethisbooktomyfamily:Jim,Judy,Kristina,andmyfriends.Youhave
mademewhatIamtoday,andforthatIthankyou.
Lifeisnotmeasuredbythenumberofbreathswetake,butbythemomentsthat
takeourbreathaway.
—EricaFrandsen


AbouttheAuthors
CaseyKochmerisacofounderoftheJSPInsiderWebsite.Aspresidentof
AmberJackSoftware,CaseyisaJavaServerPages(JSP),HTML,XHTML,
XML,DHTML,andWebservicespecialist.Hewaspreviouslyasenior
programmer,trainer,andInternetexpertforStarlingConsulting,wherehe
mentoredusersinJavaServerPages,ActiveServerPages(ASP),XMLusage,
andInternetpractices.Hisjobwastohelpcustomersintegratethelatest
technologyatanappropriatetimerelativetotheneedsofaproject.Hismantrais
thataprojectshouldimplementusableandmaintainabletechnologyratherthan
usingthelatesttechnologyfortechnology'ssake.Caseycodesandbuilds
specializedapplicationsusingJSP,ASP,andvariousdatabasesdependingon
customerneeds.Hehascoauthoredseveralbooks,includingProfessionalJSP,
SecondEditionandBeginningJSPWebDevelopment.
EricaFrandsenisanXML,ASP,andSQLServerexpert.Experiencedin
TCP/IPnetworking,sheisafounderofSoundHomeNetworks.Whileworking
asanetworkconsultant,sheinstalls,configures,andmaintainsnetworksfor

clients.Previously,EricaworkedasaprogrammerandconsultantforStarling
Consulting,whereshedesignedASPandSQLsystemsusingXML.Earlierin
hercareer,sheusedthesesametechnologiestocreateanonlinetaxpaying
systemforbusinessesinthestateofWashington.ShealsowastheWebmaster
forseveralsites.Inherfreetime,Ericabrewsbeer,playswithcomputer
hardware,andcreatesWebsitesforworthycauses.


Acknowledgments
IwouldliketothankMichelle,Mark,andMattfortheirexcellentwork.Without
theirperseverancethisbookwouldneverhavehappened.Thankyou,guys!
Also,IpaytributetoMariNowitzandNathanHamilton.Withoutmymost
excellentneighbors,Imighthavediedofstarvationandlackofinfluencefrom
therealworld.ThanksforbeingtherewhenIneededyou!
IwouldalsoliketothankSteveandBradatKundalinifortheirexcellentcoffee.
—EricaFrandsen


Introduction
ThepurposeofthisbookistoteachyouhowtoimplementXMLandWeb
serviceswithinaJSPWebapplicationorsite.Thebookwillstartverysimply
andthenworkitswayupincomplexity.Thiswillmakethebookaccessibletoa
widerangeofreaders.
ThetargetaudienceincludesnewandintermediateJSPprogrammers.However,
thisbookwillbeusefulforanyJSPprogrammerwhowantstoexpandhisorher
XMLorWebserviceimplementationknowledge.Thebookisalsogeared
towardshelpingaJSPprogrammerthinkintermsofthecombinationofJSP,
XML,andWebservices.Thegoalistoshowhowtousefullyintegratethese
technologiesintoyourprojectsandsharethelessonswehavelearnedinbuilding
Webapplications.

OnXML
WeareprogrammerswhospendquiteabitoftimebuildingWebapplications.
Overthepastfewyears,wehavebeenimplementingXMLinourprojects.
However,implementingXMLiseasiersaidthandoneattimes.Evenworse,
manytimesXMLisimplementedinwaysthatcanbeharmfultoaproject.You
shouldneveruseXMLforXML'ssake.Thisbookisareflectionofourordeals
inlearningthevarioustoolsandthemethodsofincorporatingXMLinauseful
wayintoaWebsite.
Theproblemfordevelopershasn'tbeenaboutfindinginformationonXML,but
aboutusingXMLsuccessfullywithinWebapplications.Whilethereareplenty
ofsolidXMLtitles,notitlereallyfocusesonhowtointegrateXMLintoyour
JSPproject.ThisbookiswrittenwiththeJSPdeveloperinmind.Wewantto
helpteachXML,XSL,XPath,andtheentirealphabetsoupthatgoesalongwith
XML.ByshowinghowtouseXMLwithinaJSPframework,weintendtohelp
makeimplementingXMLbotheasyandadvantageousfortheJSPdeveloper.

OnWebServices


Webservicesarethelatestfad.Theyaresonewthatmanyoftheaccompanying
toolsarestillinbetaorareonlynowbeingreleasedintothemarketplace.It'sstill
veryearlytolearnWebservices.Webservicesaretoonewforanyonetotrulybe
anexpertinthefield.ThismakeslearningWebservicesbothanexcitinganda
strangeexperience.OurintentionistoteachyouhowtoincorporateWeb
servicesintoJSP.WewillremovetheconfusionthatsurroundsWebservicesand
giveaclearpathtolearningthebasics.Thisbookwillshowthevariouselements
thatconstituteaWebservice.

OntheStructureoftheBook

Thebookisdividedintofourparts.PartIisdesignedtointroduceyoutoeachof
thetechnologiesexemplifiedthroughoutthisbook.PartIIdrillsdeeplyintothe
varioustoolsforeachofthesetechnologies.PartIIIshowshowtosuccessfully
combineallthesetechnologiestomakeyourprojecteasierandfasterto
implement.PartIVcontainsappendixesthatprovidereferencematerial.

PartI:Data,XML,andWebServicesIntroduction
Thispartisintendedtogroundyou.Wedonotassumethatyoualreadyknowa
greatdealaboutJSP,XML,orWebservices;thesethreetopicsareintroducedin
Chapters1–3.
Chapter1:IntegratingJSPandData
ThischaptershowshowtouseJSPandadatabasetogether.Thechapterserves
togroundyouinJSPandshowyouhowtoperformbasicdatabaseconnectivity.
Chapter2:IntroductiontoXML/XSL
ThischapterisawhirlwindtourofXMLandXSL.Itintroduceseachofthe
majorconceptsthatareneededforXMLandbeginsteachingXSLandXPath.
Chapter3:UnderstandingWebServices


Chapter3introducestheconceptsofWebservices.Webservicesareaconfusing
topic,andthechapterfocusesonthebasicconceptsyouwillneedtousethem.

PartII:IntegratingJSPandXML
PartIIisareviewofthetools,APIs,andlogicrequiredtosuccessfully
implementXMLandWebservices.Thesechaptersintroducethevarious
conceptsofWebservicesandthevariousparsersforXML.Onceyou'vestudied
thesechapters,youwillhaveenoughknowledgetobeginusingXMLandWeb
servicessuccessfully.
Chapter4:AQuickStarttoJSPandXMLTogether
ThischaptergivesyouaquickstarttomixingJSPandXMLtogether.The

chapterreviewsthebasicXMLAPIsandworksthroughsomeexamplesof
mergingJSPandXML.
Chapter5:UsingDOM
ThischapterteachestheimportantaspectsoftheDOMAPI.TheDOMisthe
standardsupportedbytheW3CforworkingwithanXMLfileprogrammatically.
Chapter6:ProgrammingSAX
ThischapterteachesyoutheinsandoutsoftheSAXAPI.SAXisprobablythe
mostcommonAPIusedtoreadinanXMLfile.Mostofthetime,SAXisused
automaticallybyotherXMLAPIs.However,thischapterisveryimportant
becauseunderstandingSAXiscriticalforhandlingmorecomplicatedXMLbasedprocesses.
Chapter7:SuccessfullyUsingJSPandXMLinanApplication
ThischapterintroducestheothermajorJavaXMLAPIs:JDOManddom4j.This
chapterproducesanintegratedexampleshowinghowtoworkwithJSP,XML,


andadatabase.Thegoalofthischapteristobeginwalkingyouthroughthe
integrationofXMLinanaturalwaywithinyourJSPapplication.
Chapter8:IntegratingJSPandWebServices
Chapter8examineshowtouseaWebservicewithinyourJSPsite.Thischapter
coverstwoimportantWebservicestopics.ThefirstisusingaWebservice;the
chaptershowsthemostefficientwaytouseaWebservicewithinyourJSP
application.ThesecondtopicisbuildingaWebservice;thechapterwalks
throughthecreationofaWebservicethatcanbeusedbyotherapplications.
Chapter9:AdvancedJSPandXMLTechniques
ThischapterexploresXMLconceptsthataren'tdiscussedinotherchapters.
TopicsincludeaccessingaWebservicefromanHTMLpage,XMLencoding
issues,waysofprocessinglargeXMLdocuments,andXMLtaglibraries.

PartIII:BuildingJSPSitestoUseXML
BuildingaJSPsiterequiresfarmorethanjustknowinghowtouseJSP.It

requirestheabilitytothinkintermsofbuildingaWebapplication.Web
applicationdesignisafineartthatinvolvesintegratingmanydifferenttoolsasa
seamlessunitwithinaJSPproject.Tothisend,PartIIIcoversthe
implementationofXMLandWebservicesfromanapplicationpointofview.
Thechaptersinthispartcovermanytopics,fromWebservicesecurityto
buildingXMLreportingsystems.WeshowmanydifferentfacetsofWeb
applicationdesign,fromtheservertotheoften-overlookedbrowserclient.
Chapter10:UsingXSL/JSPinWebSiteDesign
ThischapterexamineswhatispossiblebygoingbacktotherootsofJSP—or
morespecificallybyusingservlets.Thegoalofthechapteristoexaminegeneric
XMLhandling.ThismeansthattheinitialprocessingofanXMLdocumentcan
happenattheapplicationlevelratherthanatthepagelevel.Thechaptershows
howtocapturetheprocessingofanXMLpageandrouteitdirectlytoaservlet.


Chapter11:UsingXMLinReportingSystems
NomatterwhattheWebapplication,it'sasafebetthattherewillbesome
reportinginvolved.Thischapterexamineshowreportingsystemscanbenefit
fromtheappropriateplacementanduseofXML.
Chapter12:AdvancedXMLinReportingSystems
ThischapterbuildsontheexamplesinChapter11.Additionalconceptsand
topicstoenhanceanXML-basedreportingsystemareshowninthischapter's
examples.Amongtheexamplesisonethatshowshowtocreatereportsthat
showaone-to-manyrelationshipinthedatabase.
Chapter13:BrowserConsiderationswithXML
JSPdevelopersoftenoverlookclient-sideXMLprocessing.Thisisaserious
oversight,asbrowsersareagrowingandimprovingXMLclient-sidetool.This
chapterexamineshowusingthebrowsercanenhancehandlingofXMLdataand
reduceWebserverload.
Chapter14:BuildingaWebService

Inthischapter,webuildaWebservicesystemfornewsdelivery.Thecode
withinthischapterisbasedonaWebservicewithinaproductionenvironment.
ThegoalistoshowthedesignandfullintegrationofacompleteWebservice.
Chapter15:AdvancedApplicationDesign
Thischaptercoverstwotopics.First,we'llshowyouhowtobuildJSPpagesthat
updatethemselves.ThisadvancedcapabilitypermitsJSPsitestobemore
flexibleandtoexpandwhatispossiblewithXML,Webservices,andJSP.The
secondmaintopicissecurity;thechapterexamineshowtosecureyourWeb
services.


Appendixes
Theappendixessupportthematerialpresentedinthemainpartofthebook.
Theircontentsarebrieflydescribedhere.
AppendixA:SettingUp
ThisappendixcoversbasicinformationaboutsettinguptheJSPcontainerand
introducesNetBeansforthecreationofallyourJSPpages.
AppendixB:IntroductiontoJSPandHowThingsWork
FornewJSPusers,thisappendixoffersacrashcourseonJSPandhowitworks.
AppendixC:TagLibrary
ThisbookusesJSPtaglibrariesasmuchaspossible.Foruserswhoarenewto
JSP,thisappendixquicklycovershowtobuildanduseaJSPtaglibrary.
AppendixD:XSLReference
XSLisusedextensivelyinthisbook.AppendixDisareferencetothemost
commonlyusedXSLtagsandXPathfunctions.

AWordaboutSourceCode
Allthesourcecodefromthelistingsandprogramsincludedinthisbookis
availableviadownloadfromtheSamsPublishingWebsiteat
www.samspublishing.com.

Throughoutthebook,wecreatesampleclassfilesandJSPsandthenbuildon
themlaterinthesameoranotherchapter.Wheneverwedoso,weclearly
indicatewheretheoriginalfilecanbefound.Linesofcodethatshouldbeadded


orchangedareindicatedinboldfacetype.

HowtoUsetheBook
Aswementionedearlier,thisbookisgearedtowardnewandintermediateJSP
programmers.Howyouusethebook,andwhereyoubeginreading,willdepend
onyourexperiencelevel.Hereareafewtipstogetyoustarted.

ForAllUsers
Ifpossible,werecommendcodingtheexamples.Inprogramming,thebestway
tolearnisbycoding,andtheexampleshavebeengearedtoenableyoutodoso.
IfyouhaveanyquestionsaboutinitiallysettinguptheJSPcontaineror
NetBeanstocreateJSPs,refertoAppendixA.Otherwise,thefirsttimeaspecific
componentisused,itwillbereferencedforinstallationatthattime.
Inmanyrespects,codingtheexamplesisveryimportantbecausethisbook
exploresmanydifferentconcepts.Ifyoudon'twritethecode,manyofthe
conceptsarelikelytoslipbyornotsinkinasdeeplyastheyshould.Wealso
encourageyoutoexpandandtweaktheexamples.Trytobreakthecodeandfind
outwhyitbreaks.Asprogrammers,welearnbestbycodingandbyfixing
brokencode.Codingisbestlearnedbyexperience;don'tshyawayfromthis
reality.

ForNewJSPUsers
WearenotgoingtoassumethatyoualreadyknowJSPlikethebackofyour
hand.SomeonewithlittleornoJSPexperiencecanpickupthisbookandlearn
howtouseJSPandXML.Thecodeandtopicsarebuiltinalogicalandeasy

mannertohelpshowwhatisrequiredinusingXMLwithinyourJSPprojects.
BeginningJSPprogrammerswillwanttostudythechaptersinPartIclosely.The
examplesaresimpleenoughthattheywillbeagreatlearningaid.NewJSP
readerswillalsobenefitfromreadingAppendixB.

ForIntermediateJSPUsers


Thebeststartingplacewilldependonyourskills.Foruserswhoare
inexperiencedinXMLorWebservices,PartIisstillyourbestbet.Otherwise,
werecommendskimmingthefirstsection,asthereisquiteabitofinformation
withineachchapter.Thesechaptershavesomeinformationthatcanbenefitmore
experiencedreaders.However,ifyoufindthatyoualreadyknowthePartI
material,skipaheadtoPartII.

ConventionsUsedinThisBook
Thefollowingtypographicconventionsareusedinthisbook:
Codelines,commands,statements,variables,andanytextyoutypeorsee
onscreenappearsinamonotypeface.
Placeholdersinsyntaxdescriptionsappearinanitalicmono
typeface.Replacetheplaceholderwiththeactualfilename,parameter,or
whateverelementitrepresents.
Italicshighlighttechnicaltermswhenthey'rebeingintroducedanddefined.
ThebookalsocontainsNotestohelpyouspotimportantoruseful
informationmorequickly.

AFinalNote
ThisbookwaswrittenasareferenceforJSP,XML,andWebservices.Learning
thismaterialonourownwasalongprocess,andourgoalistohelpgiveJSP
developerssomeinsightsintobuildingJSPWebapplications.Thefactis,XML

andWebservicesarebothfastbecomingessentialtoolstomostJSP
applications.Theproblemistryingtolearneverythingatonce.Ourgoalwasto
provideintegratedexamplesofpracticalJSP,XML,andWebservice
implementations.Wehopethatyoubenefitfromreadingthebookasmuchaswe
benefitedfromwritingit.


PartI:Data,XML,andWebServices
Introduction
INTHISPART

1IntegratingJSPandData

2IntroductiontoXML/XSL

3UnderstandingWebServices


CONTENTS


Chapter1.IntegratingJSPandData
INTHISCHAPTER
UsingJSPwithaDatabase
OtherConsiderations
BasicDesignConcepts
Summary
Oneofthemostimportantconceptsinbuildinganyapplicationistheconceptof
data.Ourapplicationsaredrivenbydata,andthetoolsthatspecializeinthe
handlingofdataformacentralpartofanyapplication.XMLisaspecification

thatisgearedtohandledata.However,inusingXML,itquicklybecomes
importanttohaveaccesstoseveralothertools.Usuallyadatabaseisthefirst
toolthatwillbeusedalongsideXML.Oftentimes,thedataforourXMLfiles
willcomedirectlyfromadatabase.Inaddition,itwillbeimportanttoimport
datafromanXMLfileintoadatabase.Usingadatabaseisimportantenough
thatthisfirstchapterisdedicatedtoshowinghowtoaccessandsubmitdatatoa
database.
Thischapterhastwogoals.Thefirstistoshowyouhowtoaccessadatabase
fromJSP.IfyouarealreadyfamiliarwithusingadatabasewithinJSP,it's
advisablethatyouproceedtoChapter2,"IntroductiontoXML/XSL."It's
importanttonotethatseveralchaptersinthisbookwilluseadatabaseinthe
examples.Thismakessettingupatestdatabaseveryimportant.Instructionsfor
settinguptheMySQLtestdatabaseusedinalltheexamplescanbefoundin
AppendixA,"SettingUp."
ThesecondgoalistoensurethatnewerJSPprogrammershaveachancetoget
morefamiliarwithJSPbeforemovingfurtherintothebook.Thischapteris
intendedtobeextremelyaccessibletonewerJSPprogrammersregardlessof
theircurrentskilllevel.Thismeansthatthechapterisverybasic;moreadvanced
JSPprogrammerswillonlywanttoskimthischapterquickly.Programmerswho
arejuststartingtolearnaboutJSPareencouragedtofirstreadAppendix
B,"IntroductiontoJSPandHowThingsWork."


UsingJSPwithaDatabase
Thissectionwillnotcoverhowtobuildormaintainadatabase.Inaddition,due
tothevastnumberofdatabases,itwouldbeimpossibletocoverspecial
database-specificdetails.Thismeanstheexamplesherewillbekeptasgeneric
aspossibletohelpeasetheprocessofportingcodefromdatabasetodatabase.
TheexamplesinthischapterwillbeusingtheMySQLdatabase.
Tomakelifesimple,wearegoingtobuildseveralexamples.Thefirstexample

willbeusedtoenterdataintothedatabase.Thesecondexamplewillbeusedto
viewthedatainthedatabase.Thelogicintheseexamplesassumesthatthe
BannerAdstablehasbeencreatedaccordingtotheinstructionsforsettingupthe
MySQLdatabasefoundinAppendixA.

EnteringtheData
TheactualprocessofenteringdatashouldbesplitacrossseveralJSPpages.One
pagewillbeadatainputpage.Thispagewillonlyconcernitselfwithgathering
thedata.ThesecondpagewillbeanactionpagethatwillrunontheJSPserver
toprocesstheresultscreatedthroughtheinputpage.It'sagoodideatosplit
logicacrossseveralJSPpages.Thisisaperfectexampleofacaseinwhichthis
istrue.It'spossibletobuildasinglepagetoperformallthetasksoftheinputand
actionpages.Usingonepagewouldleavethecodeentangledanddifficultto
maintainwithtoomuchhappeningforasinglepage.Thisisespeciallytruewith
morecomplicateddatabasepages.Usingtwopagesmakesthelogicmoreclosely
matchtheprocessandmakesiteasierforotherprogrammerstounderstandwhat
isgoingonwithinthepages.
Theinputpage,showninListing1.1,gathersdatafromtheuserandshouldbe
savedas
webapps/xmlbook/chapter1/UpdateTableForm.jsp.
Listing1.1UpdateTableForm.jsp

<%@pagecontentType="text/html"%>


<html>
<head><title>UpdateTableForm</title></head>
<body>

<table>
<tr>
<td>Name</td>
<td></tr>
<tr>
<td>LinkText</td>
<td></tr>
<tr>
<td>Link</td>
<td></tr>
<tr><td>Action</td>
<td>
</td>
</tr>
<tr><td><inputtype="SUBMIT"value="Submit"/>
</tr>
</table>
</form>
</body>
</html>
Thisdoesn'tneedtobeaJSPpage.ItcouldbekeptasastraightHTMLpage.


However,we'vekeptitasaJSPpageoutofhabit.Typically,aninputpagesuch

asthiswouldhaveotheractivefeaturessuchassecurityvalidation,whichwould
requireittousesomeJSPprocessing.
Nowit'stimetobuildanactionpage.Thispage,whosecodeisshowninListing
1.2,willreceivethedatafromtheinputpageandthenupdatethedatabase.Save
thisfileas
webapps/xmlbook/chapter1/UpdateTableAction.jsp.
Listing1.2UpdateTableAction.jsp

<%@pageimport="java.sql.*"%>

<%
/*Step1)Getthedatafromtheform*/
Stringls_name=request.getParameter("name");
Stringls_link=request.getParameter("link");
Stringls_linktext=request.getParameter("linktext"
Stringls_action=request.getParameter("Action");

/*Step2)InitializeVariables*/
Stringls_result="Databasewasupdated";
Stringls_query="";
Stringls_dburl="jdbc:mysql://localhost/xmlboo
Stringls_dbdriver="org.gjt.mm.mysql.Driver";

/*Step3)Createaquery*/
if(ls_action.equals("new"))
{ls_query="insertintoBannerAds(name,link,
ls_query+="values(";
ls_query+="'"+ls_name+"',";
ls_query+="'"+ls_link+"',";
ls_query+="'"+ls_linktext+"')";

}