Hi all, I use a DynamicWebResource to display images previously uploaded by
user ion the context of my application. I have this DWR subclass:
class LogoResource extends DynamicImageResource {
private final IModel logoModel;
public LogoResource(IModel model) {
this.logoModel = model;
}
@Override
protected byte[] getImageData() {
String basePath = "upload/images/";
Object name = logoModel.getObject();
File file = new File(".", basePath + name);
LoggerFactory.getLogger(getClass()).info("serving file: " + file);
try {
return IOUtils.toByteArray(new FileInputStream(file));
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
}
now, when the file is found, everything is ok.
When it is not, I receive a NullPo9nterException, this is the output when
you can see my log and then the begin of the trace:
INFO - LogoResource - serving file: ./upload/images/null
ERROR - RequestCycle -
java.lang.NullPointerException
at java.io.ByteArrayInputStream.<init>(ByteArrayInputStream.java:89)
at
org.apache.wicket.markup.html.DynamicWebResource$1.getInputStream(DynamicWebResource.java:221)
at
org.apache.wicket.request.target.resource.ResourceStreamRequestTarget.respond(ResourceStreamRequestTarget.java:160)
at
org.apache.wicket.request.AbstractRequestCycleProcessor.respond(AbstractRequestCycleProcessor.java:105)
at org.apache.wicket.RequestCycle.respond(RequestCycle.java:1267)
This is annoying and, more important, it seems to cause the page not to
reload properly. In fact when after a submit I call a setResponse on the
same page, the page is not reloaded.
At the end of all the exceptions, I get:
WARN - DataRequestCycle - Completed exception handling for
request [requestcy...@1ec3ffd thread=10193...@qtp-28693170-2]
INFO - DataRequestCycle - Request ended
[requestcy...@1ec3ffdthread=10193106@qtp-28693170-2](time:
33
And the page has the same URL as before, correclty, but not the new
rendering: If I reload the page, I get the new stuff.
In the same page I have other forms, with the same setResponse onSubmit,
that work perfectly.
Do you think that these exceptions could be the problem for the undone
refresh? Or maybe is better to look elsewhere?
And, in any case, there is a clean way to avoid the getImageData to be
called if I do not have a file for the image?
Thanks.
--
Daniele Dellafiore
http://blog.ildella.net
http://twitter.com/ildella
