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Java Forum / General / October 2007jsps not serving from context root in netbeans server
I've just started using Netbeans 5.5 packaged with the sun java application server 9. I run a web app with a context root of for the sake of example "test", the default page set in web.xml to run at startup is index.jsp, that is served fine in that index.jsp simply redirects to a servlet call. The servlet executes fine, but any resultant request for a jsp seems to be requested outside of the context root instead of using the context root and a 404 is returned. So it's obvious that the server is looking in the wrong place for the JSP. The flow of my application except for startup is when a link is clicked always a servlet does some execution and then responds with a redirect to a jsp for screen display. To demonstrate: Startup -> http://localhost:8080/test/index.jsp (served ok) -> redirects to http://localhost:8080/test/someservlet -> executes ok redirects to http://localhost:8080/nextjsp.jsp So questions are: 1. why does the first jsp (index.jsp) serve fine using the context root and then 2. with any subsequent request the request for the jsp does not use the context root? Note that if I manually type in http://localhost:8080/test/nextjsp.jsp it works. Also note that in the web xml all the servlets have mappings and only index.jsp is listed as the welcome jsp. Surely not every JSP has to be listed in the web xml. I've had web apps in WSAD that didn't require this. And final note is that if I change the context root to / (well actually netbeans doesn't let just / to be entered as context root so the field has to be left as blank) a similar problem happens, because for some reason, the server decides to use a context root after all of "web". I don't understand that one either. > I've just started using Netbeans 5.5 packaged with the sun java > application server 9. I run a web app with a context root of for the [quoted text clipped - 34 lines] > for some reason, the server decides to use a context root after all of > "web". I don't understand that one either. Sorry about the duplicate, not sure what happened with google groups. Any help appreciated. Thanks. >> I've just started using Netbeans [sic] 5.5 packaged with the sun [sic] java [sic] >> application server 9. I run a web app with a context root of for the [quoted text clipped - 5 lines] >> So it's obvious that the server is looking in the wrong place for the >> JSP. You fail to show the code for how you're navigating to the view JSP. >> The flow of my application except for startup is when a link is >> clicked always a servlet does some execution and then responds with a >> redirect to a jsp for screen display. When you say "redirect", you probably should be saying "forward". The servlet should use the RequestDispatcher forward() method to get to the JSP. >> To demonstrate: >> 1. why does the first jsp (index.jsp) serve fine using the context >> root and then >> 2. with any subsequent request the request for the jsp does not use >> the context root? Because you're using redirect instead of forward(). >> Note that if I manually type inhttp://localhost:8080/test/nextjsp.jsp >> it works. Sure. >> Also note that in the web xml all the servlets have mappings and only >> index.jsp is listed as the welcome jsp. Surely not every JSP has to >> be listed in the web xml. I've had web apps in WSAD that didn't >> require this. WSAD, JBuilder, NetBeans, it doesn't matter. No, you don't need to list every JSP. >> And final note is that if I change the context root to / (well >> actually netbeans [sic] doesn't let just / to be entered as context root so '/' is not a good context root for an application. > Sorry about the duplicate, not sure what happened with google groups. Google Groups sucks.  SignatureLew > >> I've just started using Netbeans [sic] 5.5 packaged with the sun [sic] java [sic] > >> application server 9. I run a web app with a context root of for the [quoted text clipped - 7 lines] > > You fail to show the code for how you're navigating to the view JSP. Yeah good point, apologies, here it is: private void sendResponse(HttpServletResponse resp) throws IOException { resp.sendRedirect( resp.encodeURL(getJspNameToSendInResponse()) ); } > >> The flow of my application except for startup is when a link is > >> clicked always a servlet does some execution and then responds with a > >> redirect to a jsp for screen display. > > When you say "redirect", you probably should be saying "forward". The servlet > should use the RequestDispatcher forward() method to get to the JSP. See code above, by redirect I mean a response.redirect. I'm unsure of the RequestDispatcher forward() method. What I'm so curious about is why the response redirect method works in WSAD and even when I deploy a war to tomcat, but in this particular instance it doesn't. Unless I have missed something when copying across my code from the WSAD workspace in to a fresh new netbeans project. I've only just started using netbeans for the first time. > >> To demonstrate: > >> 1. why does the first jsp (index.jsp) serve fine using the context [quoted text clipped - 3 lines] > > Because you're using redirect instead of forward(). Is this an issue after my clarification and code above? If so I'd like to understand why it works when I deploy to tomcat from a WSAD workspace. > >> Note that if I manually type inhttp://localhost:8080/test/nextjsp.jsp > >> it works. [quoted text clipped - 9 lines] > > No, you don't need to list every JSP. Good. Thanks. > >> And final note is that if I change the context root to / (well > >> actually netbeans [sic] doesn't let just / to be entered as context root so [quoted text clipped - 4 lines] > > Google Groups sucks. Useful and convenient though, I can access usenet wherever I am. Thanks for your help. > > >> I've just started using Netbeans [sic] 5.5 packaged with the sun [sic] java [sic] > > >> application server 9. I run a web app with a context root of for the [quoted text clipped - 14 lines] > resp.sendRedirect( resp.encodeURL(getJspNameToSendInResponse()) ); > } Looks like some custom method that no one would have a clue about its internals :-) > > >> The flow of my application except for startup is when a link is > > >> clicked always a servlet does some execution and then responds with a [quoted text clipped - 22 lines] > like to understand why it works when I deploy to tomcat from a WSAD > workspace. [snip] I think Lew might have been referring to something like this instead: String address = "/test/nextjsp.jsp"; RequestDispatcher dispatcher = request.getRequestDispatcher( address ); dispatcher.forward( request, response ); -- Chris Dundonald wrote: >> See code above, by redirect I mean a response.redirect. I'm unsure of >> the RequestDispatcher forward() method. How about you read the Javadocs on it, then? My purpose in mentioning it was so that you would RTFM. SignatureLew > > > >> I've just started using Netbeans [sic] 5.5 packaged with the sun [sic] java [sic] > > > >> application server 9. I run a web app with a context root of for the [quoted text clipped - 17 lines] > Looks like some custom method that no one would > have a clue about its internals :-) Yeah sorry, my custom method :) But I guessed it was straight forward enough to understand ... accepts a HTTP response object, obtains the JSP name that is ready to send back to the browser after some servlet processing, encodes the URL for session state etc if required and sends it back by the redirect method. > > > >> The flow of my application except for startup is when a link is > > > >> clicked always a servlet does some execution and then responds with a [quoted text clipped - 31 lines] > request.getRequestDispatcher( address ); > dispatcher.forward( request, response ); Interesting how you have essentially hard coded the "test" context root into the address though, because essentially that would mean if anyone changed the context root of an app (in a shared dev of course) then hard coded is not too good. I'm wondering if there is a better way to dynamically put in the context root, if it's required of course? > Yeah sorry, my custom method :) But I guessed it was straight forward > enough to understand ... accepts a HTTP response object, obtains the > JSP name that is ready to send back to the browser after some servlet > processing, encodes the URL for session state etc if required and > sends it back by the redirect method. The trouble with the redirect, compared to a forward, is that redirect loses the request data and forces another round-trip to the client. A forward preserves the request and happens server side. SignatureLew > > Yeah sorry, my custom method :) But I guessed it was straight forward > > enough to understand ... accepts a HTTP response object, obtains the [quoted text clipped - 5 lines] > the request data and forces another round-trip to the client. A forward > preserves the request and happens server side. Yes I've been doing some googling and RTFMing as you advised ;) (well I was doing that anyway) but I must admit despite reading the API and a couple sites found on google so far it's still not clear how use of this method can help with maintaining context root. I may well be missing something. > Yes I've been doing some googling and RTFMing as you advised ;) (well > I was doing that anyway) but I must admit despite reading the API and > a couple sites found on google so far it's still not clear how use of > this method can help with maintaining context root. I may well be > missing something. My main points have to do with keeping the request and avoiding the round trip to the client. HttpServletResponse.sendRedirect() tells us that, "[i]f the location is relative without a leading '/' the container interprets it as relative to the current request URI. If the location is relative with a leading '/' the container interprets it as relative to the servlet container root." The leading '/' moves the redirect out of the context. I'm thinking that the "current request URI" includes not only the application context root but the specific resource handling the request. You might need to prefix the redirect URL with "../". However, I will say that most of what people want to do with a redirect is better handled by the forward mechanism. SignatureLew > > Yes I've been doing some googling and RTFMing as you advised ;) (well > > I was doing that anyway) but I must admit despite reading the API and [quoted text clipped - 17 lines] > However, I will say that most of what people want to do with a redirect is > better handled by the forward mechanism. OK I've been doing some more reading of the APIs. I now understand completely. The forward vs a redirect aside (as in the fact that the redirect sends a response back to the browser to then send another request for a specific resource), I now also understand about the context root. I have done some digging and a response.sendRedirect is still possible IF the request.getContextPath() method is used to suppliment the jsp name so for example: resp.sendRedirect( resp.encodeURL( req.getContextPath() + getJspNameToSendInResponse() ) ) or and as you have suggested I have also got it working with: getServletContext().getRequestDispatcher(getJspNameToSendInResponse()).forward(getCurrentHttpServletRequest(), resp); where the current context of the current servlet is used to obtain the dispatcher and then forward on. Thanks! So the only question I have now is, I'm assuming of course that the encodeURL as used in the sendRedirect example is negligible in the request dispatcher forward case? > getServletContext().getRequestDispatcher(getJspNameToSendInResponse()) > .forward(getCurrentHttpServletRequest(),resp); From what method are you making this call? SignatureLew > > getServletContext().getRequestDispatcher(getJspNameToSendInResponse()) > > .forward(getCurrentHttpServletRequest(),resp); > > From what method are you making this call? The code above is within a private method that is called by doPost, same method as posted in my code earlier. Except in the test I was lazy and used an already existing getCurrentHttpServletRequest() method to pull in the request object instead of updating the method signature to cater for (req, resp). >>> getServletContext().getRequestDispatcher(getJspNameToSendInResponse()) >>> .forward(getCurrentHttpServletRequest(),resp); [quoted text clipped - 5 lines] > method to pull in the request object instead of updating the method > signature to cater for (req, resp). Thank you. SignatureLew [snip] > > String address = "/test/nextjsp.jsp"; > > RequestDispatcher dispatcher = [quoted text clipped - 6 lines] > then hard coded is not too good. I'm wondering if there is a better > way to dynamically put in the context root, if it's required of course? I agree, but my intent was to show you how to use the RequestDispatcher to forward to another page, and not show you how to obtain your values dynamically. Also note, that at the time I posted my response to you, how was I to know that you were not already obtaining the values dynamically from your deployment descriptor? Anyway, it is not difficult to obtain the values you're after. You just need to investigate the API for 'ServletContext', and the methods it exposes. -- Chris Free MagazinesGet these publications absolutely FREE for up to 12 months. There are no hidden fees and no obligation. Simply choose a title, complete the application form and submit it. Read more ...
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