Re: How to handle image/gif response

Image img = new Image (GWT.getHostPageBaseURL() +"serviceexample/
ImgRetrieve");
that's the way to go

ImgRetrieve should be a servlet that sends back the image
if it receives a get request

that's explained in the link of my last post

On 20 Nov., 12:40, zhangj5 <jianzhan...@gmail.com> wrote:
> Maybe I did not explain my question correctly.
> Actually, my application is to create a registered user login
> interface. Registered user has photo stored in DB (uploaded when
> registration ), and once user login successfully, his/her photo will
> be retrieved from DB and displayed, so using the combination of form
> submit and GWT is the only solution I have found, just wondering if
> there are any other techniques can be used in this case, as this is my
> fist GWT application.
> I had tried to display image by using
> <pre>Image img = new Image( "google.com/intl/en_AL/images/
> logo.gif" );</pre>
> ,which is working as expected.
> Since my image is stored in ServletOutputStream,
> I tried to use<pre>Image img = new Image (GWT.getHostPageBaseURL() +
> "serviceexample/ImgRetrieve"); </pre>
> But image is not displayed.
>
> On Nov 19, 7:33 pm, Martin Trummer <martin.trum...@24act.at> wrote:
>
> > if you only want to display an image there's no need for a form
>
> > this might be useful:http://bit.ly/2Wgvtm
>
> > On 19 Nov., 20:22, Martin Trummer <martin.trum...@24act.at> wrote:
>
> > > what are you trying to do?
>
> > > what is the form good for?
> > > does it upload the image and afterwards you want to display this
> > > uploaded image?
>
> > > On 19 Nov., 13:01, zhangj5 <jianzhan...@gmail.com> wrote:
>
> > > > Hi all,
> > > > I have a question about how to handle image/gif type response on
> > > > client side, any suggestion will be great.
> > > > There is a service which responds for retrieving image (only one each
> > > > time at the moment) from database. The code is something like,
>
> > > > JDBC Connection
> > > > Construct MYSQL query.
> > > > Execute query
> > > > If has ResultSet, retrieve first one {
> > > > image = rs.getBlob("img"); //save image into Blob image, "img" is the
> > > > only entity in the image table.
>
> > > > }
>
> > > > Then,
> > > > response.setContentType("image/gif"); //set response type
> > > > InputStream in = image.getBinaryStream();       //output Blob image to
> > > > InputStream
> > > > int bufferSize = 1024;  //buffer size
> > > > byte[] buffer = new byte[bufferSize];           //initial buffer
> > > > int length =0;
> > > > while ((length = in.read(buffer)) != -1) {//read length data from
> > > > inputstream and store into buffer
> > > >         out.write(buffer, 0, length);           //write into
> > > > ServletOutputStream}
>
> > > > in.close();
> > > > out.flush();            //write out
>
> > > > The code on client side
> > > > ....
> > > > imgform.setAction(GWT.getModuleBaseURL() + "serviceexample/
> > > > ImgRetrieve");
> > > > ....
> > > > ClickListener {
> > > > OnClick, then imgform.submit();
>
> > > > }
>
> > > > formHandler {
>
> > > >         onSubmit, form validation
>
> > > >         onSubmitComplete
> > > >             ??????? //handle response, and display image
> > > >         Here is my question, i had tried
> > > >         Image img = new Image(GWT.getHostPageBaseURL()
> > > > +"serviceexample/ImgRetrieve");
> > > >         mg.setSize("300", "300");
> > > >         imgpanel.add(img);
> > > >         but i only got a non-displayed image with 300X300 size.
>
> > > > }
>
> > > > So, how should i handle the responde in this case?
>
> > > > Thanks,
>
>

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