Using JSP declaration tags and expression tags

I am trying to use JSP without embedding any business logic into my view pages.
I know that its not good practice to use scriptlets in pages, but is it ok to declare variables and then reference them with expression tags?
And on another note does anybody have any links to any decent jsp tutorials (I am not asking for a link to google here, or a link to a google search), by decent I mean tutorials that are not outdated and use scriptlet tags as I am trying to egt away from this.
Thanks

PaulOckleford wrote:
I am trying to use JSP without embedding any business logic into my view pages.
I know that its not good practice to use scriptlets in pages, but is it ok to declare variables and then reference them with expression tags?You can use the JSTL <c:set> for that. But I would still prefer the Servlet above that.
And on another note does anybody have any links to any decent jsp tutorials (I am not asking for a link to google here, or a link to a google search), by decent I mean tutorials that are not outdated and use scriptlet tags as I am trying to egt away from this.You can find here at least one: [http://balusc.blogspot.com/2008/07/dao-tutorial-use-in-jspservlet.html].

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JSP declaration Tag

Dear All,
Is it ok to use JSP declaration tag? I have heard if we use the declaration tag then this variable name will be shared by all threads and the particular variable will be overridden. Is it true? please advise me on this? can we use this tag in our Jsp files.
Thanking you in advance.
Regards,
Venkat

Yes, it is true that the scope of variable in decalaration tag becomes global. It is as good as declaring a public variable in core java context.
In my opinion one should avoid using the declaration tag.
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Unable to run jsp as include using jsp:include tag

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Included Content
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Populating combobox in jsp page from javabean using jsp:getProperty tag

hi,
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please reply me.
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No Sir,
I think I did not explained clearly.what I try to say is I dont want to use JSTL.I am using only Scriptlets only.I can able to receive the values from the database to the resultset.But I could not populate it in Combobox.
My code is :
<tr>
<td width="22%"><font color="#000000"><strong>Assign To Engineer</strong></font></td>
<td width="78%">
     <select NAME="Name" size="1">
<option><%=Username%></option>
</select> </td>
</tr>
in HTML
and in Scriptlets:
ps1 = con.prepareStatement
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In the server(Jboss console) I can able to display the username but I could not populate it in the Combobox .
Can you now suggest some changes in my code,Please..
Thanks a lot
With kind Regds
Satheesh

Problem with flush=true in the jsp:include tag

Hello
I have deployed a JSP based application , based on the apache struts framework. The web server is Sun One Webserver 6 Service Pack4, on a windows 2000 machine
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javax:servlet.jspexception:Illegal to flush within a custom tag
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thanks
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Gary Wang
Developer Technical Support
SUN Microsystems
http://www.sun.com/developers/support/

Flush in the jsp:include tag

should I state flush="true" every time I include a jsp using <jsp:include> tag in a jsp pages? For example I am trying to include a menu bar on the top of every jsp pages. Should I flush the buffer every time? if not, will it affect the performance?
Thank you
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Hi,
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Gary Wang
Developer Technical Support
SUN Microsystems
http://www.sun.com/developers/support/

JSP declarattion tag

hi all
I am confused on this one; please help.
In a JSP declaration tag , the variables that we declare become class's private vars upon compilation. Similarly, when we declare methods in a declaration tag they become private methods of the compiled class. Now, I wud like to know whether those vars can be accessed inthe methods???

They can be accessed in the methods, but you should restrain yourself from doing so.
<%!
int i = 100;
String name = "Bob";
public int nextInt(){
return i++;
public void setName(String name){
this.name = name;
%>The issue here is that variables declared in this manner are shared by all users of that jsp page - ie its an instance attribute of the class. Because only one instance of a servlet/jsp is created to service all requests, this attribute is shared.
The best approach is to declare variables only within your methods, and between <% %> tags.
If you need to access the variables in your methods (such as setName) pass the parameters up to them.
Cheers,
evnafets

How to call a method repeatedly with JSP custom tag?

This senerio is very similar to the usage of StringBuffer.
I have a problem which can be solved easily with scriptlets:
<% NameValuePair nvp = new NameValuePair(request.getQueryString()); %>
<a href="foo.html?<%=nvp.add(name1", "value1").add("name2", "value2").toString();%">">Foo</a>
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But I cannot use scriplets because it's turned off. I can only use jsp custom tag / jstl. How would I implement this functionality with a custom tag? How would the JSP code look like? Our container supports JSP 2.0.
Thanks.</a>

hi,
you can do within 2 step-
1) use <%@page import="your_java_class"%>
2)use scriptlet code <%...%> and write coding in this tag.
means create instance of your java class .
<% your_java_class obj1=new your_java_class();
obj1.method_of_your_java_class();
%>or
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Thanx
Ranvijay

JSP include tag not showing page content

Below is my code for a JSP page that uses JSP:include tag to include footer.jsp. The footer page does not display on show_email_entry.jsp. The error I am getting is variable emailAddress cannot be resolved. What am I doing wrong?
Here is my code.
show_email_entry.jsp
<!doctype html public "-//W3C//DTD HTML 4.0 Transitional//EN">
<html>
<%@ include file="../includes/header.htm" %>
<body>
<%
String firstName = request.getParameter("firstName");
String lastName = request.getParameter("lastName");
String emailAddress = request.getParameter("emailAddress");
%>
<h1>Thanks for joining our email list</h1>
<p>Here is the information that you entered:</p>
<table cellspacing="5" cellpadding="5" border="1">
<tr>
<td align="right">First name:</td>
<td><%= firstName %></td>
</tr>
<tr>
<td align="right">Last name:</td>
<td><%= lastName %></td>
</tr>
<tr>
<td align="right">Email address:</td>
<td><%= emailAddress %></td>
</tr>
</table>
<jsp:include page="footer.jsp" flush="true" />
<p>To enter another email address, click on the Back <br>
button in your browser or the Return button shown <br>
below.</p>
<form action="../email6/join_email_list.html" method="post">
<input type="submit" value="Return">
</form>
</body>
</html>
FOOTER.JSP page:
<%@ page import="java.util.Date" %>
<p><i><%= emailAddress %> was added on <%= new Date() %>.</p>

The [url http://java.sun.com/products/jsp/syntax/2.0/syntaxref209.html#1003408]@include directive and the [url http://java.sun.com/products/jsp/syntax/2.0/syntaxref2020.html#8828]<jsp:include> have two different functionalities.
From the [url http://java.sun.com/products/jsp/syntax/2.0/syntaxref20.html] reference page:
Include Directive : Includes a resource of text or code when the JSP page is translated.
<jsp:include>
Includes a static resource or the result from another web component
(italic emphasis is mine)
Basically the @include directive is like "copy and paste this file into the JSP and then compile"
jsp:include is "run this web page, and add the result of that to my current response"
So jsp:include can only include complete standalone JSPs.
Do you see now why it would throw an error message with your example?
Cheers,
evnafets

JSP 2.0 and EL

I want to use JSP 2.0 and EL with tomcat 5
When i use EL into a JSP Page, it seems like tomcat does not care about it and so does not interpret the EL expressions ( in the opposite, it displays the expressions )
Is there sometihng to do to force tomcat to interpret such expressions ?
Another thing. Is there something to add in the web.xml file to use JSTL 1.1 under tomcat 5? i seem to see that only <%@ taglib ...%> was required. Is it true ?
thanks

All you should need are the <%@ taglib %> and the jar files in your web-inf/lib directory.
Nothing is required in web.xml for it to work.
Make sure you are using the JSTL 1.1 taglib URIs though: http://java.sun.com/jsp/jstl/core.
They look a lot like the old ones, but include /jsp now as well.
Does the EL evaluate inside a tag? eg <c:out value="${application.servletContextName}"/>
Couple of things to try
EL evaluation may be disabled: Put this at the top of your page:
<%@ page isELIgnored=false %>
Check your web.xml for something like this (disables EL in pages)
<jsp-property-group>
<url-pattern>*.jsp</url-pattern>
<el-ignored>true</el-ignored>
</jsp-property-group>
What version of the DTD are you using for web.xml? According to the JSP spec, if it is less than 2.3, and you haven't specified handling of the EL, it is ignored.
Relevant bits of the JSP2.0 spec: JSP3.3.2, JSP 1.10.1
Can you post some code which isn't working?
Cheers,
evnafets

Using JSP declaration tags and expression tags

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