Merhaba Arkdaslar,
Bu bolumde static inclusion ve dynamic inclusion konularini inceleyecegiz’

include directive
<jsp:include>
<jsp:forward>

static inclusion

static inclusion da bir baska dosyanin icerigi mevcut JSP dosyasina translation zamaninda dahil edilir(include) ve translate sonrasinda bir tane servlet dosyasi(.java) olusur.

static inclusion; include directive kullanilarak yapilir.

Genel format ;

<%@ include file="relativeURL" %>

include directive’i sadece file attribute’u alir. file HTML , XML , txt ya da JSP dosyasi olabilir. Servlet dosyasi olamaz.

header.html

<p>header.html dosyasi baslangici</p>
<h1>header1</h1>
<h2>header2</h2>
<p>header.html dosyasi sonu</p>

includeMe.jsp

 <h1>included.jsp file</h1>

footer.txt

this is footer file content.

staticInclude.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
	pageEncoding="UTF-8"%>
<html>
<body>
	<p>include.jsp dosyamiza header.html dosyasinin icerigini ekledik.</p>

	<%@include file="header.html"%>

	<p>includeMe.jsp dosyasini ekleyelim;</p>

	<%@include file="includeMe.jsp"%>

	<p>footer.txt dosyasini ekleyelim;</p>

	<%@include file="footer.txt"%>

</body>
</html>

include directive’in calisma mantigi gayet kolaydir. header.html , includeMe.jsp , footer.txt dosyalarini include.jsp dosyamizin icerisine aktardik.

Burada dikkat etmemiz gereken nokta header.html dosyamizin icerisinde <html> <body> gibi etiketler olmamali, cunku zaten jsp dosyamizda <html> <body> etiketlerimiz mevcut.

file attribute u expression olamaz. Ornegin su kod gecersizdir , derleme hatasi verir.

<% String myURL ="copyright.html"; %>
<%@ include file="<%= myURL %>" %>

file attribute’u included edilen sayfaya parametre gecemez. Yani su kod gecersiz olacaktir ;

<%@ include file="other.jsp?name=Levent" %>

dynamic inclusion

Dynamic inclusion’da , JSP saygasina istekte bulunuldugunda , bu JSP sayfasi include edilmesi gereken dosyalar icin calisma zamaninda bir istekte daha bulunur.

dynamic inclusion olarak <jsp:include> ve<jsp:forward> standard action’lar kullanilir.

<jsp:include page="relativeURL" flush="true" />
<jsp:forward page="relativeURL" />

dynamic inclusion icin su uc yontemi de kullanabiliriz ;

dynamicInclude.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
	pageEncoding="UTF-8"%>
<html>
<body>
	
	<!-- Bu uc yontem de ayni isi yapar! dynamic inclusion -->
	
	<!-- 
	    request JSP implicit objesini kullanarak RequestDispatcher objesi elde edebiliriz.
	    include metodunu kullanarak dynamic inclusion islemini yapabiliriz
	 -->
	 
	<p>##### rd.include ##### </p>
	 
	<%
		RequestDispatcher rd = request.getRequestDispatcher("includeMe.jsp");
		rd.include(request, response);
	%>

        <p>##### pageContext.include ##### </p>
     
	<%
		pageContext.include("includeMe.jsp");
	%>

	<p>##### jsp include action ##### </p>
	
	<jsp:include page="includeMe.jsp"  />

</body>
</html>

include directive translation zamaninda calisir , <jsp:include> runtime da calisir.
include file attribute alir , jsp include page attribute alir.
static inclusion da bir tane servlet dosyasi olusur. dynamic inclusion da her jsp icin bir servlet dosyasi olusur.
Hem static inclusion’ hem dynamic inclusion kullanarak HTML ,XML , txt gibi dosyalari include islemi yapabiliriz.
Bir JSP Sayfasinda dynamic inclusion ile servlet’i include edebiliriz.
static inclusion da bu mumkun degildir.

Bir JSP dosyasi Servlet dosyasini dynamic olarak include edebilir ;

DynamicIncludeMe.java

package _12_DynamicInclude;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class DynamicIncludeMe extends HttpServlet {

	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

		PrintWriter pw = resp.getWriter();

		pw.println("DynamicIncludeMe servlet!");

	}
}

	<servlet>
		<servlet-name>DynamicIncludeMe</servlet-name>
		<servlet-class>_12_DynamicInclude.DynamicIncludeMe</servlet-class>
	</servlet>
	<servlet-mapping>
		<servlet-name>DynamicIncludeMe</servlet-name>
		<url-pattern>/dynamicIncludeMe</url-pattern>
	</servlet-mapping>

dynamicServletInclude.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
	pageEncoding="UTF-8"%>
<html>
<body>
	
	<!-- Bu uc yontem de ayni isi yapar! dynamic inclusion 
	Bir JSP Sayfasinda dynamic inclusion ile servlet'i include edebiliriz.
	-->
		 
	<p>##### rd.include ##### </p>
	 
	<%
		RequestDispatcher rd = request.getRequestDispatcher("/dynamicIncludeMe");
		rd.include(request, response);
	%>

       <p>##### pageContext.include ##### </p>
    
	<%
		pageContext.include("/dynamicIncludeMe");
	%>

	<p>##### jsp include action ##### </p>
	
	<jsp:include page="/dynamicIncludeMe"  />

</body>
</html>

page attribute’u expression olabilir ! include directive’i icin file attribute expression olamaz.

validexpression.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
	pageEncoding="UTF-8"%>
<html>
<body>


	<%
		String pageURL = "includeMe.jsp";
	%>
	
	<jsp:include page="<%=pageURL%>" />

</body>
</html>

<jsp:param>

<jsp:include> action’i body/govde alabilir. Dynamic inclusion da include edilen sayfaya parametre gecilebilir. Bunun icin <jsp:param> kullanilabilir.

Yeni bir jsp dosyasi olusturalim ;

param.jsp

<strong>${param.title }</strong>

paramInclude.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
	pageEncoding="UTF-8"%>
<html>
<body>
	
	<jsp:include page="param.jsp">
		<jsp:param name="title" value="title test" />
	</jsp:include>

</body>
</html>

<jsp:forward>

Bir JSP dosyamizdan diger JSP ya da Servlet dosyasina yonlendirme yapilabilir(forward/ request dispatch)

Bu islem 3 yontemle yapilabilir;

Yontem1 ;

forwardIt.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
	pageEncoding="UTF-8"
%>

<html>
<body>

	<p>forwardIt.jsp , bu kismi goremeden handleIt.jsp dosyasina forward edilecek. </p>
	<jsp:forward page="handleIt.jsp"></jsp:forward>

</body>
</html>

handleIt.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>

<html>
<body>
        <h1>forwarded by dispatchMe.jsp</h1>
        <h1>This is handleIt.jsp</h1>
</body>
</html>

Dikkat edecek olursak forwardIt.jsp dosyamizdan , handletIt.jsp dosyamiza forward etttik fakat url forwardIt.jsp olarak kaldi.

forward islemi yapmadan once out.print out.flush gibi metotlar kullanilirsa ;

java.io.IOException: Error: Attempt to clear a buffer that’s already been flushed

Yontem 2 ;

forwardIt2.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
	pageEncoding="UTF-8"%>

<html>
<body>

	<%
		pageContext.forward("handleIt2.jsp");
	%>

</body>
</html>

Yontem 3 :

dispatchMe.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
	pageEncoding="UTF-8"%>

<html>
<body>

	<%
		RequestDispatcher rd = request.getRequestDispatcher("handleIt3.jsp");
		rd.forward(request, response);
	%>

</body>
</html>

handleIt3.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
	pageEncoding="UTF-8"%>

<html>
<body>

	<h1>Dispatched by dispatchMe.jsp</h1>
	<h1>This is handleIt3.jsp</h1>

</body>
</html>

Yazimi burada sonlandiriyorum.
Herkese Bol Javali Gunler dilerim.
Be an oracle man , import java.*;
Levent Erguder
OCP, Java SE 6 Programmer
OCE, Java EE 6 Web Component Developer

Servlet & JSP – 25 – Static Inclusion & Dynamic Inclusion

static inclusion

dynamic inclusion

<jsp:param>

<jsp:forward>

Leave a Reply Cancel reply