Unit 4 - JSP-Part II

8/9/2019 Unit 4 - JSP-Part II

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Dr. Thomas Tran CSI3140 Lecture Notes based on Dr. Jeffre Jacson!s

Cha%ter &Se%arat#n' ro'ramm#n' and

resentat#on)JS Techno"o'y

CSI3140*** Structures+ Techn#,ues+ and Standards


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JS -%ress#on Lan'ua'e (-L$

/ JS -%ress#on Lan'ua'e (-L$ maes #t%oss#b"e to eas#"y access a%%"#cat#on datastored #n Jaaeans com%onents.


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${visits+1}#s an eam%"e of an -Le%ress#onembedded #n a JS document

25 #s the synta used #n JS documents tomar the conta#ned str#n' as an -Le%ress#on

6n -L e%ress#on can occur

/ In tem%"ate data) ea"uates to Jaa String/ 6s (%art of$ the a"ue of certa#n JS attr#butes)

ea"uates to data ty%e that de%ends on contet


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/ -L "#tera"s)

true+ false

dec#ma" #nte'er+ f"oat#n' %o#nt+ sc#ent#f#c7notat#on numer#c "#tera"s

str#n's (s#n'"e7 or doub"e7,uoted$

null


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/ -L ar#ab"e names) "#e Jaa

Can conta#n "etters+ d#'#ts+ 8 + and 2

9ust not be'#n :#th a d#'#t

9ust not be resered :ords)


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/ -L o%erators) ;e"at#ona") + =+ ==+ !=

/ ect notat#on$ arentheses for 'rou%#n'


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/ -L automat#c ty%e coners#on

6dd#t#on #s a":ays numer#c #n -L (? does notre%resent str#n' concatenat#on$


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/ -L %ro#des a number of #m%"#c#t ob>ects

/ 9ost of these ob>ects are re"ated to but

not the same asthe JS #m%"#c#t ob>ects JS #m%"#c#t ob>ects cannot be accessedd#rect"y by name #n an -L e%ress#on+ but canbe accessed #nd#rect"y as %ro%ert#es of one of

the -L #m%"#c#t ob>ects


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#ageontet) %ro#des access to JS #m%"#c#tob>ects -) -L e%ress#on #ageontet.request#s

reference to the JS requestob>ect

#age) JS #m%"#c#t ob>ect re%resent#n' theser"et #tse"f

/ JS ob>ects #age+ request+ session+ and

a##li'ationa"" hae get/ttri0ute2andset/ttri0ute2methods These ob>ects store -L sco%ed ar#ab"es (e.g.+

visits$


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/ @ar#ab"e reference such as visits:#th#n an -Le%ress#on #s reso"ed #n one of t:o :ays) If the ar#ab"e reference #s #dent#ca" to the name of

one of the -L #m%"#c#t ob>ects+ then the reference

ea"uates to the #nd#cated #m%"#c#t ob>ect. If the ar#ab"e reference does not match one of the -L

#m%"#c#t ob>ect names+ then the JS #m%"#c#t ob>ects#age+ request+ session+ and a##li'ationaresearched 7 #n that order for an attr#bute ha#n' the

'#en ar#ab"e name./ If not found+ a"ue #s null/ If found+ a"ue #s 304e't

JS automat#ca""y casts th#s a"ue as needed


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/ 6"" -L #m%"#c#t ob>ects ece%t#ageontet#m%"ement Jaa 9a%#nterface

/ In -L+ can access 9a% us#n' array orob>ect notat#on) Ser"et) request.get5ara"eter6#172

-L)#ara"8#19,or#ara".#1


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/ 6rray=L#st access)

If -L sco%ed ar#ab"e a:arre%resents/ Jaa arrayA or

4ava.util.;ist

and #f -L sco%ed ar#ab"e indecan be cast to#nte'er

then can access e"ements of a@ar by/ a@arB#nde

/ a@ar.#nde


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/ unct#on ca""

unct#on name fo""o:ed by %arenthes#Eed+comma7se%arated "#st of -L e%ress#on

ar'uments Ta' "#brar#es def#ne a"" funct#ons

unct#on names usua""y #nc"ude a names%ace

%ref# assoc#ated :#th the ta' "#brary


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JS 9aru%

/ Three ty%es of maru% e"ements) Scr#%t#n'

/ -) s'ri#tlet

/ Inserts Jaa code #nto ser"et D#rect#e

/ -) dire'tive.#age

/ Instructs JS trans"ator

6ct#on/ Standard) %ro#ded by JS #tse"f

/ Custom) %ro#ded by a ta' "#brary such as JSTL


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JS 9aru%

/ T:o JSF d#rect#es dire'tive.#ageA some attr#butes)

'ontent#e

session) falseto turn off use of session

ob>ecterror5age) re"at#e G;L of a%%"#cat#on resource

to be re,uested #f an uncau'ht ece%t#on occurs #nth#s JS document

isrror5age) true to access -L #m%"#c#te'e#tionob>ect

dire'tive.in'lude) #m%ort :e""7formedF9L


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JS 9aru%

/ JSTL #s d##ded #nto seera" funct#ona" areas+each :#th #ts o:n names%ace)

Names%ace %ref# #s

H ta'"#b %ref#Kcur#Khtt%)==>aa.sun.com=>s%=>st"=core M


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JS 9aru%


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JS 9aru%

/ Common ar#ab"es)

var/ ;e%resents name of a sco%ed ar#ab"e that #s

ass#'ned to by the act#on/ 9ust be a str#n' "#tera"+ not an -L e%ress#on

s'o#e

/ S%ec#f#es sco%e of sco%ed ar#ab"e as one of the"#tera"s #age+ request+ session+ ora##li'ation


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JS 9aru%

setact#on Sett#n' (and creat#n'$ a sco%ed ar#ab"e

Sett#n'=creat#n' an e"ement of %a#

/ 6ctua""y+ th#s fa#"s at run t#me #n J*SD 1.3 (:h#chtreats -L #m%"#c#t ob>ect %a#s as read7on"y$

9a%

ey


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setact#on

/ H ta'"#bur#Khtt%)==>aa.sun.com=>s%=>st"=core%ref#Kc M

/ Hhtm"M HheadM Ht#t"eMHc)setM Ta'-am%"eH=t#t"eM H=headM

/ HbodyM Hc)set arKsa"ary

sco%eKsess#on a"ueK2O000PO5=MHc)out a"ueK2sa"ary5=M

/ H=bodyM H=htm"M


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/ H ta'"#b ur#Khtt%)==>aa.sun.com=>s%=>st"=core%ref#Kc M Hhtm"M HheadM Ht#t"eMHc)remoeMTa' -am%"eH=t#t"eM H=headM

/ HbodyM Hc)set arKsa"ary sco%eKsess#ona"ueK2O000PO5=M H%Mefore ;emoe @a"ue)

/ Hc)out a"ueK2sa"ary5=M

/ H=%M

/ Hc)remoe arKsa"ary=M

/ H%M6fter ;emoe @a"ue) Hc)out a"ueK2

sa"ary5=MH=%M/ H=bodyM H=htm"M


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JS 9aru%

outact#on Norma""y used to :r#te a str#n' to the outJS

#m%"#c#t ob>ect

6utomat#ca""y esca%es F9L s%ec#a"characters

If a"ue #s nullout%ut #s em%ty str#n'/


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JS 9aru%

urlact#on valueattr#bute #s a G;L to be :r#tten to theoutJS #m%"#c#t ob>ect

G;L!s be'#nn#n' :#th are assumed re"at#eto contet %ath

#ara"e"ements can be used to def#ne

%arameters that :#"" be G;L encoded


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JS 9aru%

/ 6"ternat#e to the valueattr#bute (setand #ara"e"ements$ If e"ement has content+ th#s #s %rocessed to

%roduce a Stringused for value

-en oute"ement :#"" %roduce str#n'+ not:r#te to the outob>ect

6ss#'ns a"ue of ar#ab"e"ess(F9L esca%ed$ tosco%ed ar#ab"e 'lean


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JS 9aru%

ifact#on Qenera" form #nc"udes sco%ed ar#ab"e to rece#e

testa"ue

/ The aboe maru% creates (or sets+ #f ar#ab"e a"ready e#sts$a sco%ed ar#ab"e named test?esult#n the defau"t #agesco%e and+ #f the cond#t#on #s true+ sends the conta#nedcharacter data to the outob>ect

6ss#'ned oo"ean a"ue

of testattr#bute


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H ta'"#bur#Khtt%)==>aa.sun.com=>s%=>st"=core

%ref#Kc M Hhtm"M HheadM Ht#t"eMHc)#fMTa' -am%"eH=t#t"eM H=headM

HbodyM

Hc)set arKsa"ary sco%eKsess#ona"ueK2O000PO5=M

Hc)#f testK2sa"ary M O0005M

H%M9y sa"ary #s) Hc)out a"ueK2sa"ary5=MH%M

H=c)#fM H=bodyM H=htm"M


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JS 9aru%

'@ooseact#on


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JS 9aru%

fora'@act#on Gsed to #ncrement a ar#ab"e (:r#tes O+ 4+ R+ & to the

out ob>ect$)

Gsed to #terate oer a data structure (#terates throu'h@eader-L #m%"#c#t ob>ect and out%uts a "#stconta#n#n' one #tem for each header f#e"d #n the TT

re,uest be#n' %rocessed$)


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JS 9aru%

fora'@act#on Can #terate oer array+ %a#+ olle'tion+Gterator+ nu"eration

-"ements of 9a% are %a#.ntr+ :h#chsu%%ort ey and a"ue -L %ro%ert#es)


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Jaaeans C"asses

/ JSTL Core act#ons are des#'ned to beused for s#m%"e+ %resentat#on7or#ented%ro'ramm#n' tass

/ 9ore so%h#st#cated %ro'ramm#n' tassshou"d st#"" be %erformed :#th a "an'ua'esuch as Jaa

/ Jaaeanstechno"o'y a""o:s a JSdocument to ca"" Jaa methods


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Jaaeans C"asses

/ -am%"e

/ ;e,u#rements) Jaaeans c"ass must

e #u0li'and not a0stra't Conta#n at "east one simple property design pattern

method (def#ned "ater$


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Jaaeans C"asses

/ Gs#n' a Jaaeans c"ass #n JS


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Jaaeans C"asses

/ Gs#n' a Jaaeans c"ass as sho:n)

C"ass must hae a defau"t(no7ar'ument$constructorto be #nstant#ated by useHean

/ 6utomat#ca""y su%%"#ed by Jaa #n th#s eam%"e

C"ass shou"d be"on' to a %aca'e(ao#dsneed for an i"#ort$

/ Th#s c"ass :ou"d 'o #n DH-GIJ'lasses"d#rectory

/ Instance of a Jaaeans c"ass #s a bean


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Jaaeans C"asses

/ S#m%"e %ro%erty des#'n %atterns T:o ty%es) 'etter and setter

/ oth re,u#re that the method be #u0li'

/ 'etter) no ar'uments

returns a a"ue (#.e.+ cannot be o#d$

name be'#ns :#th get(or is+ #f return ty%e #s 0oolean$fo""o:ed by u%%er case "etter

/ setter) one ar'ument (same ty%e as 'etter return a"ue$

@o#d (#.e.+ must not return a a"ue$

name be'#ns :#th setfo""o:ed by u%%er case "etter


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Jaaeans C"asses

/ -L ca""s s#m%"e %ro%erty des#'n method #nres%onse to access of bean %ro%erty)

6ttem%t to read %ro%erty 'enerates ca"" to

assoc#ated get=ismethod (or error #f nonee#sts$

6ttem%t to ass#'n a"ue to %ro%erty 'enerates

ca"" to assoc#ated setmethod (or error$


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Jaaeans C"asses

/ -am%"e settermethod

/ Ca""#n' setter from JS


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Jaaeans C"asses

/ S#m%"e %ro%erty des#'n %attern methodsassoc#ate bean %ro%ert#es:#th beans Name of bean %ro%erty obta#ned by remo#n'

'et=#s=set method %ref# and fo""o:#n' the ru"e)/ If rema#n#n' name be'#ns :#th t:o or more u%%er

case "etters+ bean %ro%erty name #s rema#n#n'name) set/:alue2/:alue

/ If rema#n#n' name be'#ns :#th a s#n'"e u%%er case"etter+ bean %ro%erty name #s rema#n#n' name :#thth#s "etter conerted to "o:er case)getDel'o"e2Ael'o"e


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Instant#at#n' eans

/ eans can be #nstant#ated by a ser"et andmade aa#"ab"e to JS #a sco%e ob>ects

Ser"et

JS) no need for useHeanact#on

${sessionS'o#e.testHean.Ael'o"e}


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Instant#at#n' eans

useHeanon"y #nstant#ates a bean #f onedoes not a"ready e#st+ can o%t#ona""y%erform #n#t#a"#Eat#on

-a"uated on"y #f useean #nstant#ates Testean


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Gs#n' eans

/ -am%"e)mort'a'eca"cu"at#on


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Gs#n' eans

Ca"" to'etayment($method


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Jaa 6I ean ro%ert#es

/ 9any Jaa 6I methods conform tos#m%"e %ro%erty des#'n %atterns

/ Can usua""y treat as bean %ro%ert#es


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Ta' L#brar#es

/ *ou"dn!t #t be n#cer to :r#te the mort'a'ea%% as


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Ta' L#brar#esGsed so s#n'"e root


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Ta' L#brar#es

/ "ace custom ta' def#n#t#on #n a ta' f#"eha#n' the name of the custom act#on

"ortgage.tag

/ "ace ta' f#"e #n a ta' "#brary(e.g.+d#rectory conta#n#n' ta' f#"es$

DH-GIJtags

/ 6dd names%ace dec"arat#on for ta' "#brary


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9@C

/ 9any :eb a%%s are based on the 9ode"7@#e:7Contro""er (9@C$ arch#tecture %attern

Contro""er

9ode" Com%onents

@#e:

TTre,uest

TTres%onse


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9@C

/ Ty%#ca" JS #m%"ementat#on of 9@C

Contro""er(Jaa ser"et$

9ode" Com%onents(beans+ D9S$

@#e:

(JS document$

TTre,uest

TTres%onse


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9@C

/ or:ard#n' an TT re,uest from aser"et to another com%onent)

y G;L

y name

-) =e""oCounter.>s%


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9@C


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9@C

/ o: does the contro""er no: :h#chcom%onent to for:ard to

get5at@Gnfo2a"ue of G;L!s can be used

-am%"e)/ ser"et ma%%#n' %attern #n Ae0."l)

/ G;L ends :#th)get5at@Gnfo2returns)


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9@C

/ JS in'ludeact#on (not the same as thein'luded#rect#eU$

-ecute s%ec#f#edcom%onent and#nc"ude #ts out%ut#n %"ace of the#nc"ude e"ement


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9@C

/ 6dd#n' %arameters to the requestob>ectseen by an #nc"uded com%onent)

requestob>ect seen by nav0ar.4s#:#"" #nc"ude%arameter named 'urrent5age:#th a"ue @o"e

Unit 4 - JSP-Part II

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