JSP/SERVLETS

Transcripción

JSP/SERVLETS

JSP/SERVLETS
ISIS 3710
Aplicaciones Web
Servidor/Contenedor web
-
Lógica de negocio
Procesamiento
computacionalmente costoso
Bases de datos SQL/NoSQL
CDNs: content deliver network
Motores de minería de datos, BI
Servidor
Componentes del lado
del servidor: JSP, JSF, PHP, EJBs
Aplicaciones Web
Solicitud HTTP
Componente
del lado
del servidor
Aplicaciones Web
Solicitud HTTP
Contenido que puede
ser interpretado/visualizado
del lado del cliente
Componente
del lado
del servidor
Servlet
-
Componente del lado del servidor que se implementa
como una clase en Java
-
Recibe datos del cliente embebidos en una solicitud
HTTP
-
Retorna datos al cliente embebidos en una respuesta
HTTP
Servlet: formas de uso
1. Generación directa de un flujo de contenido sobre el
HTTP response: HTML quemado, archivo a descargar
HTML
Servlet
2. Controlador en una aplicación web
Vista
Servlet
Modelo
Generación directa de un flujo de contenido sobre el
HTTP response: HTML quemado, un archivo a descargar
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class HelloWorld extends HttpServlet {
public void doGet(HttpServletRequest req, HttpServletResponse res)
throws ServletException, IOException {
res.setContentType("text/html");
PrintWriter out = res.getWriter();
out.println("<HTML>");
out.println("<HEAD><TITLE>Hello World</TITLE></HEAD>");
out.println("<BODY>");
out.println("<BIG>Hello World</BIG>");
out.println("</BODY></HTML>");
}
}
*Ejemplo tomado de: http://www.servlets.com/
import java.io.*;
}
}
import java.io.*;
}
}
import java.io.*;
}
}
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the respons*E
*Ejemplo tomado de: Head First Servlets and JSPs, 2nd Edition. Bryan Basham, Kathy Sierra, Bert Bates. 2008
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Servlet como controlador
Contenedor
1
Browser
Cliente
Lógica del
contenedor
2
Servlet
(controlador)
<form method="POST" action="SelectBeer.do">
Seleccione el tipo de cerveza <p>
<select name="color" size="1">
<option value="1"> Rubia </option>
<option value="2"> Ambar </option>
<option value="3"> Brown Ale </option>
<option value="4"> Oscura </option>
</select>
<input type = "submit">
</form>
URL de mapeo del servlet o JSP
Seleccione el tipo de cerveza <p>
<select name="color" size="1">
<option value="1"> Rubia </option>
<option value="2"> Ambar </option>
<option value="3"> Brown Ale </option>
<option value="4"> Oscura </option>
</select>
</form>
Servlet como controlador (mapeo)
package jsplab.view;
…
@WebServlet(name = "Controller", urlPatterns = {“/SelectBeer.do"})
public class Controller extends HttpServlet {
…
}
<servlet>
<servlet-name>Controller</servlet-name>
<servlet-class>jsplab.view.Controller</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>Controller</servlet-name>
<url-pattern>/SelectBeer.do</url-pattern>
</servlet-mapping>
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Parámetros con múltiple valor
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Context
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Request
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Java Server Pages
-
Componente del lado del servidor para generar
contenido del lado del cliente
-
En un esquema MVC, las JSP asumen el rol de la vista
que genera solicitudes al controlador y pinta los datos
proporcionados por este último
-
Permiten embeber código Java y expresiones Java
junto con HTML/CSS/JS para generar contenido
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JSP
Java Server Pages
JSP: Traducción y Compilación
Traducción
JSP
Compilación
Servlet
.class
-
Esto se hace solo la primera vez que se accede a la JSP
-
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PXVLF0DSSXW³'-´³%7´
PXVLF0DSSXW³,QGLH´³)URX)URX´
UHTXHVWVHW$WWULEXWH³PXVLF0DS´PXVLF0DS
En un servlet
6WULQJ>@PXVLF7\SHV ^³$PELHQW´³6XUI´³'-´³,QGLH´`
UHTXHVWVHW$WWULEXWH³0XVLF7\SH´PXVLF7\SHV
7KLV'2(6ZRUNLQD-63
Cuál es el resultado
en una JSP?
Music is ${musicMap[“Surf”]}
0XVLFLV^PXVLF0DS>0XVLF7\SH>@@`
becomes
0XVLFLV^PXVLF0DS>³$PELHQW´@`
becomes
0XVLFLV=HUR
KWWSORFDOKRVWWHVW-637HVWHUGR
0XVLFLV=HUR
,QDVHUYOHW
En un servlet
7KLV'2(6ZRUNLQD-63
en una JSP?
Music is ${musicMap[“Surf”]}
0XVLFLV^PXVLF0DS>0XVLF7\SH>@@`
becomes
Music is becomes
Tahiti 80
0XVLFLV=HUR
0XVLFLV=HUR
JSP EL:
Expression
Language
,QDVHUYOHW
En un servlet
,QDVHUYOHW
MDYDXWLO0DSPXVLF0DS
QHZMDYDXWLO+DVK0DS
6WULQJ>@PXVLF7\SHV
^³$PELHQW´³6XUI´³'-´
7KLV'2(6ZRUNLQD-63
7KLV'2(6ZRUNLQD-63
en una JSP?
0XVLFLV
^PXVLF0DS>0XVLF7\SH>@@`KWWSORFDOKRVWWHVW-637HVWHUGR
0XVLFLV
^PXVLF0DS>0XVLF7\SH>@@`
becomes
0XVLFLV=HUR
becomes
becomes
0XVLFLV=HUR
becomes
0X
JSP EL:
Expression
Language
,QDVHUYOHW
En un servlet
,QDVHUYOHW
MDYDXWLO0DSPXVLF0DS
QHZMDYDXWLO+DVK0DS
6WULQJ>@PXVLF7\SHV
^³$PELHQW´³6XUI´³'-´
7KLV'2(6ZRUNLQD-63
7KLV'2(6ZRUNLQD-63
en una JSP?
0XVLFLV
^PXVLF0DS>0XVLF7\SH>@@`KWWSORFDOKRVWWHVW-637HVWHUGR
0XVLFLV
becomes
0XVLFLV=HUR
becomes
becomes
Music is
Zero 7
0XVLFLV=HUR
becomes
0X
,QDVHUYOHW
En un servlet
7KLV'2(6ZRUNLQD-63
Cuál es el resultado 0XVLFLV
Music
is ${musicMap.Indie}
0XVLFLV=HUR
en una JSP?
becomes
becomes
0XVLFLV=HUR
,QDVHUYOHW
En un servlet
7KLV'2(6ZRUNLQD-63
Cuál es el resultado 0XVLFLV
Music
is ${musicMap.Indie}
0XVLFLV=HUR
en una JSP?
becomes
Music is becomes
Frou Frou
0XVLFLV=HUR
);\ZQVOQVLM`Q[KWMZKML\WIVQV\NWZIZZIa[IVL
JSP2EMEMBERFOLKSTHISIS./4*AVA)N%,THE;=OPERATORIS./4THEARRAYACCESS
EL: Expression Language
4HE%,FORACCESSINGANARRAYISTHESAMEASTHE%,FORACCESSINGA,IST
OPERATOR.OITSJUSTCALLEDTHE;=OPERATOR7ESWEARLOOKITUPINTHESPECITH
NAME*USTTHESYMBOL;=,IKE0RINCEKINDOF)FIT$)$HAVEANAMEITWOULDBE
ARRAY,IST-APBEAN0ROPERTYACCESSOPERATOR
,QD6HUYOHW
MDYDXWLO$UUD\/LVWIDYRULWH)RRG QHZMDYDXWLO$UUD\/LVW
IDYRULWH)RRGDGG³FKDLLFHFKUHDP´
IDYRULWH)RRGDGG³IDMLWDV´
IDYRULWH)RRGDGG³WKDLSL]]D´
IDYRULWH)RRGDGG³DQ\WKLQJLQGDUNFKRFRODWH´
UHTXHVWVHW$WWULEXWH³IDYRULWH)RRGÍDYRULWH)RRG
En un servlet
,QD-63
overridd
ce
ni
a
s
ha
t
is
L
ay
rr
A
ly
us
io
bv
)RRGVDUHÎDYRULWH)RRG` O
en una JSP?
Foods are ${favoriteFood}
)RRGVDUH>FKDLLFHFKUHDPID
MLWDVWKDLSL]]DDQ\WKLQJLQ
GDUNFKRFRODWH@
)LUVWIRRGLVÎDYRULWH)RRG>@`
right
,IWKHW
WKHEUD
D/LVW
6WULQJ
FRHUFH
7KLVZ
ÎDYRU
,QD6HUYOHW
En un servlet
,QD-63
overridd
ce
ni
a
s
ha
t
is
L
ay
rr
A
ly
us
io
bv
en una JSP?
Foods are ${favoriteFood}
GDUNFKRFRODWH@
,IWKHW
WKHEUD
D/LVW
6WULQJ
FRHUFH
[chai ice cream, fajitas, thai
pizza,
t
righ
7KLVZ
anythingÎDYRULWH)RRG>@`
in dark chocolate]
)LUVWIRRGLV
ÎDYRU
,QD6HUYOHW
En un servlet
,QD-63
overridd
ce
ni
a
s
ha
t
is
L
ay
rr
A
ly
us
io
bv
en una JSP?
Food is ${favoriteFood[0]}
GDUNFKRFRODWH@
right
,IWKHW
WKHEUD
D/LVW
6WULQJ
FRHUFH
7KLVZ
ÎDYRU
,QD6HUYOHW
En un servlet
,QD-63
overridd
ce
ni
a
s
ha
t
is
L
ay
rr
A
ly
us
io
bv
en una JSP?
Food is ${favoriteFood[0]}
GDUNFKRFRODWH@
right
Food is chai ice cream
,IWKHW
WKHEUD
D/LVW
6WULQJ
FRHUFH
7KLVZ
ÎDYRU
,QD6HUYOHW
En un servlet
,QD-63
overridd
ce
ni
a
s
ha
t
is
L
ay
rr
A
ly
us
io
bv
en una JSP?
Food
is ${favoriteFood[“3”]}
GDUNFKRFRODWH@
right
,IWKHW
WKHEUD
D/LVW
6WULQJ
FRHUFH
7KLVZ
ÎDYRU
,QD6HUYOHW
En un servlet
,QD-63
overridd
ce
ni
a
s
ha
t
is
L
ay
rr
A
ly
us
io
bv
en una JSP?
Food
is ${favoriteFood[“3”]}
GDUNFKRFRODWH@
right
Food is anything in dark chocolate
,IWKHW
WKHEUD
D/LVW
6WULQJ
FRHUFH
7KLVZ
ÎDYRU
En un servlet
String[] favoriteMusic ={“Reggeaton”, “Champeta”,
“Vallenato”, “Joropo”, “Calypso”};
request.setAttribute(“musicList”, favoriteMusic);
en una JSP?
Music is ${favoriteMusic}
En un servlet
en una JSP?
Music is ${favoriteMusic}
Music is
En un servlet
en una JSP?
Music is ${musicList}
En un servlet
en una JSP?
Music is ${musicList}
Music is [Ljava.lang.String;@d29dd9]
Asuma que la variable fulano no existe. Cuál sería el resultado
de las siguientes expresiones en una JSP:
Mi amigo se llama ${fulano}
${7 + fulano}
${8 / fulano}
${5 - fulano}
${6 % fulano}
${7 < fulano}
${7 == fulano}
${fulano == false}
${7 + fulano}
${8 / fulano}
${5 - fulano}
${6 % fulano}
${7 < fulano}
${7 == fulano}
${fulano == false}
Mi amigo se llama
${7 + fulano}
${8 / fulano}
${5 - fulano}
${6 % fulano}
${7 < fulano}
${7 == fulano}
${fulano == false}
Mi amigo se llama
7
${7 + fulano}
${8 / fulano}
${5 - fulano}
${6 % fulano}
${7 < fulano}
${7 == fulano}
${fulano == false}
Mi amigo se llama
7
Infinity
${7 + fulano}
${8 / fulano}
${5 - fulano}
${6 % fulano}
${7 < fulano}
${7 == fulano}
${fulano == false}
Mi amigo se llama
7
Infinity
5
${7 + fulano}
${8 / fulano}
${5 - fulano}
${6 % fulano}
${7 < fulano}
${7 == fulano}
${fulano == false}
Mi amigo se llama
7
Infinity
5
Excepción !!
${7 + fulano}
${8 / fulano}
${5 - fulano}
${6 % fulano}
${7 < fulano}
${7 == fulano}
${fulano == false}
Mi amigo se llama
7
Infinity
5
Excepción !!
false
${7 + fulano}
${8 / fulano}
${5 - fulano}
${6 % fulano}
${7 < fulano}
${7 == fulano}
${fulano == false}
Mi amigo se llama
7
Infinity
5
Excepción !!
false
false
${7 + fulano}
${8 / fulano}
${5 - fulano}
${6 % fulano}
${7 < fulano}
${7 == fulano}
${fulano == false}
Mi amigo se llama
7
Infinity
5
Excepción !!
false
false
true
0RYLHOLVW
$PHOLH
5HWXUQRIWKH.LQJ
0HDQ*LUOV
Ciclos haciendo uso de scriptlets:
,QD-63ZLWKVFULSWLQJ
WDEOH!
6WULQJ>@LWHPV 6WULQJ>@UHTXHVWJHW$WWULEXWH³PRYLH/LVW´
6WULQJYDU QXOO
IRULQWL LLWHPVOHQJWKL^
YDU LWHPV>L@
!
WU!WG! YDU!WG!WU!
`!
WDEOH!
FKDSWHU
$K"NWZ-IKP&
4HECFOR%ACHTAGFROMTHE*34,ISPERFECTFORTHISITGIVESYOU
ASIMPLEWAYTOITERATEOVERARRAYSANDCOLLECTIONS
-63FRGH
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(WeÕll talk ab in the chapter.)
directive later
#WDJOLESUH¿[ ´F´XUL ´KWWSMDYDVXQFRPMVSMVWOFRUH´!
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EU!EU!
WDEOH!
FIRU(DFKYDU ´PRYLH´LWHPV ´^PRYLH/LVW`´!
WU!
WG!^PRYLH`WG!
WU!
FIRU(DFK!
WDEOH!
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<tr> stand
Condicional simple
<c:if test =“${usertype == ‘root’}”>
……
</c:if>
Condicional múltiple
<c:choose>
<c:when test=“…”>
……
</c:when>
<c:otherwise>
……
</c:otherwise>
</c:choose>

JSP/SERVLETS

Transcripción

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