On Tue, 2 Apr 2002, Micael Padraig Og mac Grene wrote:
> Date: Tue, 02 Apr 2002 22:29:28 -0800
> From: Micael Padraig Og mac Grene <[EMAIL PROTECTED]>
> Reply-To: Tomcat Users List <[EMAIL PROTECTED]>
> To: [EMAIL PROTECTED]
> Subject: Images and STRUTS
>
> I tried to do an ordinary image tag with the struts application, and could
> not. What is happening with that? I could not get the index.jsp page to
> reference an image in the same location. I used the same page without
> struts, and it worked. I am just getting the clue on struts. I am
> familiar with the whole of Model 2 architectures, just not struts. Is it
> the forwarding mechanism that is calling the problem?
You probably want to ask this sort of question on the STRUTS-USER list
instead of here, but here's a common scenario that can cause Struts users
(or anyone else using an architecture that uses RequestDispatcher.forward)
grief: if you are using relative path references for your images, those
paths get resolved against the request URI that the browser submitted to
-- not the URI of the page itself. This is because the browser has no
clue that a RequestDispatcher.forward() call was done on the server side.
Example:
- Your app is installed at "http://localhost:8080/myapp";
- You have a main page "index.jsp", which therefore has the absolute URI
"http://localhost:8080/myapp/index.jsp";.
- You have an image in an "images" subdirectory, which therefore has the
absolute URI "http://localhost:8080/myapp/images/logo.gif";.
- You have Struts set up to use path based mapping to the controller
servlet, so you get URIs like "http://localhost:8080/myapp/do/getCustomer";
in it (to execute the "getCustomer" action).
Now, consider what happens if you have the following tag in index.jsp:
<img src="images/logo.gif">
and you execute "http://localhost:8080/myapp/do/mainMenu";. This fails to
retrieve the image. Why? Because the *browser* is the one that resolves
the absolute URI of the image -- and it resolves it against the URI that
it submitted for this request:
http://localhost:8080/myapp/do/images/logo.gif
which is obviously wrong. Ways to get around this:
- (Struts-specific) Use extension mapping instead of path mapping
for the controller. Then, all requests and pages are in the same
"directory level" and relative references work as expected.
- (Struts-specific) Use the <html:base/> tag in the <head> section
of your index.jsp page. This creates an HTML <base> tag that tells
the browser to base relative references on *this* page, instead of
the request URI of the submit.
- (Struts-specific) Use the Struts <html:img> tag instead, which knows
all about this problem and generates the correct URI automatically.
- (General) Use a relative path like "../images/logo.gif" to convince
the browser to do the path correctly.
- (General) Include your own <base> tag to tell the browser what the
absolute URL of this page is.
>
> Micael
>
Craig
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![http://localhost:8080/myapp/images/logo.gif"](http://localhost:8080/myapp/images/logo.gif"){kind=link}
