Java Strangeness...

[Scott Batchelor]

Ok here is a scenario I am seeing. I am debugging my app and I am using this block of code to do a redirect:
try {
response.sendRedirect(url);
LOG.debug("Redirect URL = " + url);
} catch (IOException e) {
//
}
When I step throught his code it actually hit the line: response.sendRedirect(url);
And the url variable is correct in the logs.
But it doesnt send the app anywhere just continues on.
Any thoughts.
I hope this isnt to vague but I am stumped as to what could be causing this.
Scott

[Bear Bibeault]

The sendRedirect method actually doesn't perform the redirect in-line. What it does is to set up the headers on the response to instruct the user agent (usually a browser) to initiate a new request using the header information.
So you won't see anything happen until after your servlet completes and the response is sent back to the browser.
hth,
bear

[Pavel Halas]

I give you a good advice. Never use empty catch block. You're going to tear your hair one day...
This is MUCH better:

 try {
            response.sendRedirect(url);
            LOG.debug("Redirect URL = " + url);
        } catch (IOException e) {
            e.printStackTrace();
        }

[Bear Bibeault]

P.S. This would have been better asked in the Servlets forum. Nudge. Wink.

[Bear Bibeault]

Actually, to address the exception issue, here's the idiom I use all over the code:

} catch (IOException ioe) {
   throw new ServletException( "IO error performing redirect: " + ioe.getMessage(), ioe );
}

If an exception is thrown, you rarely want to eat it and just move on -- even if you have logged it. That's the purpose of the ServletException and why it can wrap a root cause exception (in this case the IOE).
hth,
bear