Dear Rob,
If I understand your email correctly, you are interested to know 'why'
rather than 'how'.
Let me try to explain.
Eventhough JSP looks like ASP, the working is not similar. The JSP file is
compiled into a Java Servlet, the very first time it is executed.
Subsequent calls, the Java Servlet is executed, until you make some changes
in the original JSP file.
The whole script you write between <% and %> and the html tags between them
are compiled together to become part of the service() method of the servlet.
This method is executed every time a servlet is called.
The content in <%! and %> becomes a part outside the sevice(). So your
method testMethod() becomes a seperate method outside the service(), in the
servlet.
Now, when you execute the servlet, the service has 2 parameters request and
response, which takes care of the communication. The Writer is bound to the
response. In JSP 'out' is the default Writer. All the html you have is
equivalent to writing out.print("some html code"). The scope of 'out' is
only within the service() method. the scope of response also is limited to
the service() method.
Since testMethod() being outside service(), that does not understand 'out'
or 'response'. In the servlet, your method will look something like this.
testMethod()
{
out.print("<p align='center'>How are you today?</p>");
}
This method does not understand 'out', so gives error.
The best way to solve the problem is rewriting the method like,
String testMethod()
{
String retStr="<p align='center'>How are you today?</p>";
return retStr;
}
and calling it in the main JSP page as
<%= testMethod() %>
I have not tried it, so please excuse me if it does not work. But logically
it should work, and I believe it explains your question. Also, if you pass
'out' to the testMethod() and write the method as given above, in the JSP,
it should work(again logically).
Best regards,
Dantus
----- Original Message -----
From: Rob L'Estrange <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Sunday, March 18, 2001 8:02 AM
Subject: Re: Inner scriptlet tags
> Thanks for your reply Sachin. :)
>
> You seem to be saying "Well of course you can't do that within declaration
> tags. Go and read up on JSP tags to improve your understanding" hehe.
Thanks
> for the advice, but I'm not sure you fully understood my question. It's a
> legitimate one I think. Let me expand...
>
> The supplied syntax is illegal for JSP because JSP translators consciously
> reject HTML embedded in method declarations. We're in agreement on that -
> they are built to work that way, no arguments.
>
> My question is: "Why? Why are the JSP translators built not to accecpt
HTML
> embedded in method declarations?". I'm not saying that JSP should or that
it
> shouldn't support this syntax; my goal is to understand if there is a good
> reason why JSP translators work this way. For all I know, there is a very
> good reason. As mentioned, JSPs primary competitor (ASP) does accept the
> syntax, and this is very handy. And, I do think there is an argument along
> the lines of, "Well the whole idea of server pages is the blend of HTML
and
> code. Why not support HTML embedding even within declarations of methods?"
>
> I can see that if this were to work, the declared method with the embedded
> HTML would have to have a signature that included a JSPWriter parameter.
> Beyond that, I can't see a barrier to translators being able to handle
HTML
> embedded in method declarations. But I accept that just because I cannot
see
> a problem, that there isn't one. Hence my query to this list.
>
> What do you think? Is there a good reason why this syntax is not
supported?
> Or, perhaps, it is supported by some vendors and not others?
>
> Rob
>
>
> ----- Original Message -----
> From: "Sachin S. Khanna" <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>
> Sent: Friday, March 16, 2001 11:39 PM
> Subject: Re: Inner scriptlet tags
>
>
> > Well <! .... > this is a jsp declaration and not a scriptlet.
> > There has been a lot of discussion on the difference, use of jsp
> declaration
> > and scriptlets.
> > All of which can be found at the mail archives of this list.
> > Please help yourself as well as this list by searching for them out
there.
> > Have a nice day.
> > With regards,
> > Sachin S. Khanna.
> > www.emailanorder.com
> >
> > ----- Original Message -----
> > From: Rob L'Estrange <[EMAIL PROTECTED]>
> > To: <[EMAIL PROTECTED]>
> > Sent: Sunday, March 18, 2001 3:42 AM
> > Subject: Inner scriptlet tags
> >
> >
> > > Hi All
> > >
> > > I've been developing with ASP for sometime and have finally got around
> to
> > > checking out JSP.
> > >
> > > I've come across something curious. In the source code at the bottom
of
> > this
> > > email, the highlighted code would be permissible (semantically) in ASP
> but
> > > is not permissible in JSP. I'm using Tomcat 3.2.
> > >
> > > I understand where the translator is "breaking down" and why - in
short,
> > the
> > > translator has been built not to process scriptlet tags within a
> > declaration
> > > tag. And I understand that there are ways of achieving the same
result,
> > and
> > > that not all people would see this feature as necessary. But... I have
> > found
> > > the technique useful in ASP development - which is the same as saying,
> for
> > > me at least, the technique is useful in server page development. Is
> there
> > a
> > > good reason why JSP translators are not built to handle this kind of
> > syntax?
> > >
> > > Thanks
> > > Rob
> > >
> > > ==================================
> > >
> > > <%@ page language="Java" %>
> > >
> > > <%!
> > >
> > > private void testMethod(){
> > > /* Start: Here's the violating code. */
> > > %>
> > > c > > <%
> > > /* End: The violating code. */
> > > }
> > >
> > > %>
> > >
> > > <html>
> > > <head>
> > > <title>Hello</title>
> > > </head>
> > >
> > > <body bgcolor="#FFFFFF">
> > > <h1 align="center"><font face="Arial"
color="#0000FF">Hello</font></h1>
> > >
> > > <%
> > > testMethod();
> > > %>
> > >
> > > </body>
> > > </html>
> > >
> > >
> >
>
===========================================================================
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> > JSP-INTEREST".
> > > For digest: mailto [EMAIL PROTECTED] with body: "set JSP-INTEREST
> > DIGEST".
> > > Some relevant FAQs on JSP/Servlets can be found at:
> > >
> > > http://java.sun.com/products/jsp/faq.html
> > > http://www.esperanto.org.nz/jsp/jspfaq.html
> > > http://www.jguru.com/jguru/faq/faqpage.jsp?name=JSP
> > > http://www.jguru.com/jguru/faq/faqpage.jsp?name=Servlets
> > >
> >
> >
>
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> > Some relevant FAQs on JSP/Servlets can be found at:
> >
> > http://java.sun.com/products/jsp/faq.html
> > http://www.esperanto.org.nz/jsp/jspfaq.html
> > http://www.jguru.com/jguru/faq/faqpage.jsp?name=JSP
> > http://www.jguru.com/jguru/faq/faqpage.jsp?name=Servlets
>
>
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> To unsubscribe: mailto [EMAIL PROTECTED] with body: "signoff
JSP-INTEREST".
> For digest: mailto [EMAIL PROTECTED] with body: "set JSP-INTEREST
DIGEST".
> Some relevant FAQs on JSP/Servlets can be found at:
>
> http://java.sun.com/products/jsp/faq.html
> http://www.esperanto.org.nz/jsp/jspfaq.html
> http://www.jguru.com/jguru/faq/faqpage.jsp?name=JSP
> http://www.jguru.com/jguru/faq/faqpage.jsp?name=Servlets
>
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For digest: mailto [EMAIL PROTECTED] with body: "set JSP-INTEREST DIGEST".
Some relevant FAQs on JSP/Servlets can be found at:
http://java.sun.com/products/jsp/faq.html
http://www.esperanto.org.nz/jsp/jspfaq.html
http://www.jguru.com/jguru/faq/faqpage.jsp?name=JSP
http://www.jguru.com/jguru/faq/faqpage.jsp?name=Servlets
