My database logic is abstracted using dynamic taglets. I don't have any
hardcoded java in the .jsp itself.
So, basically what you are doing is doing ALL the database logic before the
JSP. This doesn't really make the most programming sense in my case.
For example, supposed I have a query which is supposed to loop many times,
depending on some parameters from the previous form. I would need to buid
some huge arrays to store all the sql results so I can print them out later
in the form.
How do you get around doing this? Or do you just get the result set, then
manipulate it further down in your JSP?
At 10:38 AM 4/29/99 -0600, you wrote:
>I personally prefer to keep all database access out of JSP pages -- in fact,
>I prefer to minimize the amount of Java in JSP pages as much as possible. I
>believe our approach would solve your redirect problem:
>
>We do all database access and most Java logic in a servlet we call a
>JSPPageLoadHandler. Each JSP page that requires set-up with data from the
>database has a corresponding load handler. This servlet fetches the data
>from the database and checks for error conditions. If it encounters an
>error, it puts an error message object into the session and redirects to the
>appropriate JSP page, which takes the error message object out of the
>session and displays it. If the queries were successful, the data is placed
>into the session, and the servlet redirects to the JSP page. This JSP page
>gets the data out of the session and displays it. Similarly, if a JSP page
>is a form, the form submit calls its JSPPageProcessHandler (servlet) which
>reads the data from the form and validates it. If the data is valid, it
>writes it to the database, writes a success message to the session, and
>redirects to a page that displays the success message. If the validation
>fails, it sticks an error message into the session and redirects to the
>original JSP page, which displays the error message as well as redisplays
>the form.
>
>What we like about this approach is that almost all of our Java is in a
>servlet, which never writes to the output stream. Our web staff can make
>the JSP pages as pretty as they'd like without worrying about stepping all
>over our Java, and our Java code is mostly in servlets and entirely free of
>HTML.
>
> -- Kyal
>----------------------------------------------------
>Kyallee Dalrymple [EMAIL PROTECTED]
>Software Engineer (303)-277-1997 x108
>Polygon Network, Inc. http://www.polygon.net/
>----------------------------------------------------
>
>-----Original Message-----
>From: A mailing list for discussion about Sun Microsystem's Java Servlet
>API Technology. [mailto:[EMAIL PROTECTED]]On Behalf Of Neal
>Kaiser
>Sent: Thursday, April 29, 1999 9:56 AM
>To: [EMAIL PROTECTED]
>Subject: Re: An alternative to sendRedirect() or
>RequestDispatcher.forward()
>
>
>I've realized one problem (and am still looking for a good solution). Let
>me explain how a sample JSP flows:
>
><Database Query is Done>
>Things printed to PrintWriter
><Another Database Query is Done>
>This printed
>...etc
>
>Now my <Database Query Done> tags can do a sendRedirect if there is an
>error executing the SQL.
>
>So, say my first database query is done, then things are printed, then the
>second query bombs. It will try to do a sendRedirect, which ofcourse won't
>work because the servlet output stream has been written to. (Aside note,
>this DID work with build 131 - but according to the spec, it probably
>shouldn't have).
>
>As I see it, my options are to either:
>
>1) Do all queries at the top of the JSP before any HTML is printed. The way
>the JSPs are structured, this would not really be acceptable.
>
>2) Somehow have my "out" PrintWriter really be a buffer. Then, when
>everthing is done, print to the real output stream. I'm not sure how
>possible this would be....
>
>Any other ideas?
>
>Thanks.
>
>At 09:25 AM 4/29/99 -0400, you wrote:
>>I am using the latest JRun build (140) and much of my JSP functionality is
>>failing. In many of my JSPs, I do some preliminary processing of a
>>request, and if certan conditions are met, I forward the request to another
>>JSP for processing.
>>
>>I do all this BEFORE anything is written to the PrintWriter (Servlet
>>OutputSteam). This previously worked w/ build 131, but now doesn't. I've
>>tried the RequestDispatcher.forward() also, no luck. In reading the spec,
>>it says "You cannot use this method if the PrintWriter object has been
>>obtained from the response..."
>>
>>Well, when JRun compiles a JSP to a JAVA file, one fo the first lines in
>>the service() method is:
>>
>>PrintWriter out = new PrintWriter (new BufferedWriter( new
>>OutputStreamWriter(Response.getOutputStream())),true)
>>
>>How can I get around this? I want to be able to forward requests, but
>>cannot because getOutputStream has been called.
>>
>>Thanks,
>>
>>Neal Kaiser
>>
>>------------------------------------------------------------
>>To unsubscribe, send email to [EMAIL PROTECTED]
>>and include in the body of the message "unsubscribe jrun-development".
>>
>>
>
>___________________________________________________________________________
>To unsubscribe, send email to [EMAIL PROTECTED] and include in the body
>of the message "signoff SERVLET-INTEREST".
>
>Archives: http://archives.java.sun.com/archives/servlet-interest.html
>Resources: http://java.sun.com/products/servlet/external-resources.html
>LISTSERV Help: http://www.lsoft.com/manuals/user/user.html
>
>
___________________________________________________________________________
To unsubscribe, send email to [EMAIL PROTECTED] and include in the body
of the message "signoff SERVLET-INTEREST".
Archives: http://archives.java.sun.com/archives/servlet-interest.html
Resources: http://java.sun.com/products/servlet/external-resources.html
LISTSERV Help: http://www.lsoft.com/manuals/user/user.html
