How to use GWT when downloading Files with a Servlet?
- by molleman
Hello Guys
I am creating a simple project that will allow me to upload and download files using gwt. i am having trouble with the downloading of files that are on my server.
For the file upload i used http://code.google.com/p/gwtupload/ and followed the instructions there. My file is stored on the server outside of the website container(on the hard drive),
Now when it comes to the downloading of a file, i want a user to press a download button and whatever item is currently selected will download. i dont really know how this will be done
i know i need a download servlet
public class DownloadAttachmentServlet extends HttpServlet {
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
// TODO Auto-generated method stub
super.doGet(req, resp);
}
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
String fileName = (String) req.getSession().getAttribute("fileName");
YFUser user = (YFUser) req.getSession().getAttribute(TestServiceImpl.SESSION_USER);
if (user == null)
throw new ServletException("Invalid Session");
InputStream in = null;
OutputStream out = resp.getOutputStream();
FileInputStream fIn = new FileInputStream(fileName);
byte[] buffer = new byte[4096];
int length;
while ((length = in.read(buffer)) > 0){
out.write(buffer, 0, length);
}
in.close();
out.flush();
}
}
for the moment i will just pass a fileName string to retrieve the file for testing
now i am lost at what to do on the client side, i have a simple
public class DownloadFilePanel extends Composite {
public DownloadFilePanel(final YFUser user , final String fileName){
final Element downloadIframe = RootPanel.get("__download").getElement();
VerticalPanel content = new VerticalPanel();
content.add(new Label("Download For this File : " + fileName));
Button button = new Button("Download");
button.addClickHandler(new ClickHandler(){
@Override
public void onClick(ClickEvent event) {
// i do not know what to do here
});
content.add(button);
initWidget(content);
}
}
above is a simple widget that will supply a panel that will allow for the download of a file based on a fileName
as you can see above, i do not know what to do to be able to download the file
is there any one that can point me in the right direction?
