Thank you for the advice. Here's the solution I came up with, in case
it's useful to anyone else.
First I used the DownloadLink as a template for my "blobDownloadLink".
Then I created an InputStreamResourceStream, which is essentially a
barely modified version of Wicket's FileResourceStream, taking an
InputStream as the constructor parameter instead of a File. The code for
both of those is below.
While this solution works, the two issues still hanging in my mind are:
1. I'm sure there's an easier way to get the InputStream into an
IResourceStream than to create an InputStreamResourceStream class...I
just couldn't figure out what it is.
2. When I get the Blob from the database like this,
rs.getBinaryStream(1);
the returned BinaryStream doesn't work. Doing this,
java.sql.Blob blob = rs.getBlob(1);
return blob.getBinaryStream();
doesn't work either. So I ended up doing,
java.sql.Blob blob = rs.getBlob(1);
byte[] bytes = new byte[(int)blob.length()];
try {
blob.getBinaryStream().read(bytes);
} catch (IOException ioe) {
// handle it
}
return new ByteArrayInputStream(bytes);
Not pretty, but it works.
*******
// Relevant code for blobDownloadLink
Link blobDownloadLink = new Link("blobDownloadLink") {
@Override
public void onClick() {
InputStream inputStream =
//getBlobAsInputStreamFromDatabase();
IResourceStream resourceStream =
new InputStreamResourceStream(inputStream);
getRequestCycle().setRequestTarget(new
ResourceStreamRequestTarget(resourceStream)
{
public String
getFileName()
{
return
//theFileNameYouWantAssociatedWithThisDownload;
}
public void
respond(RequestCycle requestCycle)
{
super.respond(requestCycle);
}
});
try {
inputStream.close();
} catch (IOException ioe) {
logger.error("Error
attempting to close inputStream in blobDownloadLink.", ioe);
}
};
};
********
// Relevant code for InputStreamResourceStream
import java.io.IOException;
import java.io.InputStream;
import org.apache.wicket.util.resource.AbstractResourceStream;
import org.apache.wicket.util.resource.ResourceStreamNotFoundException;
/**
* An InputStreamResourceStream is an IResource implementation for
files.
*
* @see org.apache.wicket.util.resource.IResourceStream
* @see org.apache.wicket.util.watch.IModifiable
* @author Dane Laverty
*/
public class InputStreamResourceStream extends AbstractResourceStream
{
private static final long serialVersionUID = 1L;
/** Resource stream */
private transient InputStream inputStream;
/**
* Constructor.
*
* @param inputStream
* [EMAIL PROTECTED] InputStream} containing resource
*/
public InputStreamResourceStream(InputStream inputStream)
{
this.inputStream = inputStream;
}
/**
* Closes this resource.
*
* @throws IOException
*/
public void close() throws IOException
{
if (inputStream != null)
{
inputStream.close();
inputStream = null;
}
}
/**
* @see IResourceStream#getContentType()
*/
public String getContentType()
{
// Let ResourceStreamRequestTarget handle content-type
automatically
return null;
}
/**
* @return A readable input stream for this resource. The same
input stream is returned until
* <tt>InputStreamResourceStream.close()</tt> is
invoked.
*
* @throws ResourceStreamNotFoundException
*/
public InputStream getInputStream() throws
ResourceStreamNotFoundException
{
if (inputStream == null)
throw new
ResourceStreamNotFoundException("InputStream could not be found");
return inputStream;
}
}
-----Original Message-----
From: Igor Vaynberg [mailto:[EMAIL PROTECTED]
Sent: Friday, October 10, 2008 3:37 PM
To: [email protected]
Subject: Re: Downloading a BLOB
i didnt say use the downloadlink, i said see how it works...
-igor
On Fri, Oct 10, 2008 at 3:32 PM, Dane Laverty
<[EMAIL PROTECTED]> wrote:
> DownloadLink appears to accept only a file pathname. If I understand
it
> correctly, the only way I could use that would be to read the BLOB
into
> a file on the server, and then have the DownloadLink point to that
file.
> I believe that would require me to have the file created when the page
> is generated, rather than when the link is clicked. Since there are
> going to be many links on this page, I would rather be able to wait
> until the user clicks the link to stream the BLOB to them.
>
> -----Original Message-----
> From: Igor Vaynberg [mailto:[EMAIL PROTECTED]
> Sent: Friday, October 10, 2008 3:26 PM
> To: [email protected]
> Subject: Re: Downloading a BLOB
>
> see how downloadlink works
>
> -igor
>
> On Fri, Oct 10, 2008 at 3:21 PM, Dane Laverty
> <[EMAIL PROTECTED]> wrote:
>> The title basically says it all. I've got a BLOB in a database, and I
>> want the user to be able to click a link and download it. Any wicket
>> solutions to do this? Thanks much.
>>
>>
>>
>>
>
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