Hi, here is the code in the (non rpc) plain vanilla servlet, which
sends the image to the client.
I upload the image with a FileUpload Widget. On the server side, I
have a variation of the Apache commons FileUpload servet. This puts
the bytes in the database (with Hibernate, in my case) This generates
a primary key. This I pass back to the client with
response.setHeader("id", id);
And then the client calls a servlet ImageServlet like this:
public void setTargetImage() {
// hack to prevent browser caching.
Long timestamp = System.currentTimeMillis();
String s = "?ts=" + timestamp.toString();
String theBytes = GWT.getHostPageBaseURL() +
"ImageFromUploadServlet" + s;
targetImage = new Image(theBytes);
targetPanel.clear();
targetPanel.add(targetImage);
}
public class ImageFromUploadServlet extends
javax.servlet.http.HttpServlet {
private static final long serialVersionUID = 1L;
private static Logger logger = Logger
.getLogger("ac.otago.flags.server.ImageFromUploadServlet");
public void init() throws ServletException {
}
/**
* Gets the image. If a user (http session) has uploaded many images,
this
* method will retrieve the latest one.
*
*/
protected void doGet(HttpServletRequest request,
HttpServletResponse response) throws ServletException,
IOException
{
String ID = request.getSession().getId();
Provider provider = new Provider();
// get all uploads for this user (session)
Upload[] uploads = provider.getUploadsByUserid(ID);
// get the most recent one
Upload latestUpload = uploads[0];
// logging
logger.debug("user " + ID + " has uploaded " + uploads.length +
"
files" );
// get the image as bytes
byte[] image = latestUpload.getImage();
response.setContentType("image/jpeg");
// stream out the bytes
BufferedOutputStream bout = new BufferedOutputStream(response
.getOutputStream());
for (int i = 0; i < image.length; i++) {
bout.write(image[i]);
}
bout.flush();
bout.close();
logger.debug("streaming image completed");
}
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException,
IOException
{
doGet(request, response);
}
}
I hope this helps. Let me know if you need more information.
With kind regards from New Zealand,
Michel
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