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Web Component Certification (OCEJWCD)

How to run jstl program

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posted 17 years ago

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Hi,

As written in HF I copied the jstl.jar inside the WEB-INF/lib folder as specified below.

C:\Program Files\Apache Software Foundation\Tomcat 6.0\webapps\ch9-forEach\WEB-INF\lib\jstl.jar

But still I am not getting the output. Control is going to jsp and when I am using scriptlets, output is fine. But <c:forEach/> tag isn't working.

Code for your reference
===============
<%@ page import="com.example.Model.*" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
<HEAD>
<TITLE> SuperHit Moveis.jsp</TITLE>
</HEAD>
<BODY>
The super hit movies of ${param.actor} are:
<%
String[] movies = (String[])request.getAttribute("movieNames");
for(int i=0;i<movies.length;i++)
{ %>
<%= movies[i] %> 
<% }%>

<c:forEach var="movie" items="${movieNames}" >
${movie}
</c:forEach>
</BODY>
</HTML>

Thanks,
Satya

Regards, Satya SCJP,SCWCD

Louis Moloney

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posted 17 years ago

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you need to tell the page about the tag lib

stick somthing like this at top of page

<%@ taglib uri="http://java.sun.com/jstl/core" prefix="c" %>

satya mahapatra

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posted 17 years ago

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Thanks Louis.

Now it is able to recognize <c:forEach> tag. When I gave something like this

<c:forEach var="i" begin="1" end="10" step="1">
${i}
</c:forEach>

its printing the nos.

but the below code isn't working.

<c:forEach var="movie" items="${movieNames}" >
${movie}
</c:forEach>

Log file error message
========================
Aug 1, 2007 5:31:29 AM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet Hi threw exception
org.apache.jasper.JasperException: /result.jsp(12,0) According to TLD or attribute directive in tag file, attribute items does not accept any expressions
=============
It showing attribute itens doesn't accept any expression. Why this?

If you have any clue pls help.

Thanks,
Satya

Regards, Satya SCJP,SCWCD

Michael Ku

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posted 17 years ago

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What type of object is movieNames? It has to be some kind of a collection.
Would you please post the code that puts the variable name 'movieNames' into some kind of a scope as an atttribute.

One of the most common mistakes is to declare the variable 'movieNames' at the page level but not place it into one of the avaialbe attribute scopes.

satya mahapatra

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posted 17 years ago

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The problem is solved. The taglib uri that Louis has specified in the above message:
<%@ taglib uri="http://java.sun.com/jstl/core" prefix="c" %>

He has missed jsp(typing mistake I guess ), thats why the problem. The correct uri is

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

Anyway thanks guys for your support.

Regards, Satya SCJP,SCWCD

Michael Ku

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posted 17 years ago

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Satya, I am confused. you previously said that this code worked
______________
<c:forEach var="i" begin="1" end="10" step="1">
${i}
</c:forEach>
_______________
but when you tried to use a collection it did not.

If the problem was an incorrect uri, then both of the examples that you gave should not have worked. If one worked but the other did not, then what changed ?

Michael Ku

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posted 17 years ago

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Satya, I would like to compliment you for trying to code the examples you are finding in HF. It is the best way to learn. If you continue to try and learn this way, you will have no problem passing the exam

satya mahapatra

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posted 17 years ago

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Hi Michael,

You have pointed it correct. "If the problem was an incorrect uri, then both of the examples that you gave should not have worked."

So once again I tried this. As happens before this time also the same thing.Means it worked for <c:forEach var="i" ....> but didn't work for collection. I don't know why this. Or may be I am doing some mistakes.

Anyway thanks once again for your support.

Thanks,
Satya

Regards, Satya SCJP,SCWCD

Michael Ku

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posted 17 years ago

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Again, movieNames needs to be in one of the attribute scopes or else this will not work. Would you please provide the code that places movieNames into one of the attribute scopes?

khushhal yadav

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posted 17 years ago

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Hi Satya

I tried this code and it's working fine.
The only thing which I have done is that I have also put standard.jar in /WEB-INF/lib as it provides library's implementation classes. jstl.jar provides API classes.

My Servlet Code:

package scwcd;

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class TestServlet1 extends HttpServlet
{
public void doPost(HttpServletRequest request, HttpServletResponse
response)throws IOException, ServletException
{
java.util.ArrayList movieNames = new java.util.ArrayList();
movieNames.add("Pan's Labyrinth");
movieNames.add("My Sassy Girl");
movieNames.add("Black Hawk Down");

request.setAttribute("movieNames", movieNames);
request.setAttribute("person", p);

RequestDispatcher view = request.getRequestDispatcher("result.jsp");
view.forward(request, response);
}

public void doGet(HttpServletRequest request, HttpServletResponse response)
throws IOException, ServletException
{
doPost(request, response);
}
}

JSP code

<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<%@ page isELIgnored="false"%>
<html><body>

<c:forEach var="i" begin="1" end="10" step="1">
${i}
</c:forEach>
 

<c:forEach var="movie" items="${movieNames}">
${movie} 
</c:forEach>

</body></html>

And Output is:

1 2 3 4 5 6 7 8 9 10
Pan's Labyrinth
My Sassy Girl
Black Hawk Down

Regards,
Khushhal

rgrds,
Khushhal

satya mahapatra

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Posts: 134

posted 17 years ago

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Hi Michael,

Find the below code for your reference.

package com.example.Web;

import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;

import com.example.Model.*;

public class SelectMovie extends HttpServlet
{
public void doPost(HttpServletRequest req,HttpServletResponse res)
throws IOException,ServletException
{
System.out.println("*****Coming inside servlet class*****");
res.setContentType("text/html");
PrintWriter out=res.getWriter();
String name = req.getParameter("actor");
System.out.println("Get the name from form:::::"+name);
getServletContext().log("*****************INSIDE SELECTNAME SERVLET CLASS***********");
movieModel movies = new movieModel();
System.out.println("Before calling getMovies method in servlet class");
List movieNames = movies.getMovies(name);
System.out.println("In servelt class movie names are:::::"+movieNames);
req.setAttribute("movieNames",movieNames);
System.out.println("After If blocks=========");
RequestDispatcher view = req.getRequestDispatcher("result.jsp");
view.forward(req,res);
}
}

Regards, Satya SCJP,SCWCD

Marc Peabody

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posted 17 years ago

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From external source found from a Google search:

Error Message: According to TLD or attribute directive in tag file, attribute items does not accept any expressions. When working on a J2EE (Java Enterprise Edition) web application with JSTL (JSP Standard Tag Library), this is a pretty common error.

Reason for this error is version incompatibility between JSP, Servlet and JSTL. Matching versions are listed below.

* JSP 1.2 , Servlet 2.3 , JSTL 1.0
* JSP 2.0 , Servlet 2.4 , JSTL 1.1

More info can be found through the link.

A good workman is known by his tools.

Shanika Wijerathna

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posted 17 years ago

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But hey i have a problem.. when we just copy and paste the jar file to our application, where we declare the uri of the standard tag library. i mean we dont declare it in our web.xml file. Then how container know the uri. i checked the content of jar file its just having a set of class files and META-INF directory and inside the META-INF it has MANIFEST.mf. i'm assuming that JSTL also just another taglibrary
ok thanks

Shanika Wijerathna(scjp)

Christophe Verré

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posted 17 years ago

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Did you also copy standard.jar ?
http://faq.javaranch.com/view?SetupJstlForJsp2

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satya mahapatra

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posted 17 years ago

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Hi Christophe,

Yah I have copied the standard.jar and jstl.jar in WEB-INF\lib folder.

Thanks,
Satya

Regards, Satya SCJP,SCWCD

Christophe Verré

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posted 17 years ago

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Sorry, I was asking Shanika, who doesn't understand why the uri is set. If he/she could try to look into standard.jar's META-INF...
[ August 07, 2007: Message edited by: Christophe Verre ]

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Shanika Wijerathna

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posted 17 years ago

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Hi Christophe
Yeah I didn't copy the standard.jar before and didn't check the content of it. And now I have found the relevant TLDs inside the MATA-INF of standerd.jar. thanks

Shanika Wijerathna(scjp)

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