Problem in sending image from applet to servlet

Question

dear friends,
i have a need to send an image from applet to servlet via HttpConnection and getting back that image from applet.
i am struggling with this sice many hours and got tired by searching any post that would help me but haven't got yet.
i tried using this code but it dosent make any execution sit right. i got NPE at ImageIcon.getDescription() line;
at applet side
      jf.setContentPane(getJContentPane());
                 FileDialog fd=new FileDialog(jf,"hi");
                 fd.setMode(FileDialog.LOAD);
                 fd.setVisible(true);   
                 v=new Vector();
                 try{                                                
                           FileInputStream fis=new FileInputStream(new File(fd.getDirectory()+fd.getFile()));      
                           byte[] imgbuffer=new byte[fis.available()];
                           fis.read(imgbuffer);
                           ImageIcon imgdata=new ImageIcon(imgbuffer);
                           v.add(0,imgicon);
                            String strwp ="/UASProject/Storeimage";              
                            URL servletURL = new URL(getCodeBase(),strwp);             
                            HttpURLConnection servletCon = (HttpURLConnection)servletURL.openConnection();       
                            servletCon.setDoInput(true); 
                            servletCon.setDoOutput(true);
                            servletCon.setUseCaches(false);
                            servletCon.setDefaultUseCaches(false);   
                            servletCon.setRequestMethod("POST");     
                            servletCon.setRequestProperty("Content-Type", "application/octet-stream");   
                            servletCon.connect();            
                            ObjectOutputStream oboutStream = new ObjectOutputStream(servletCon.getOutputStream());                     
                            oboutStream.writeObject(v);
                            v.remove(0);
                            oboutStream.flush();      
                            oboutStream.close();  
                            //read back from servlet
                            ObjectInputStream inputStream = new ObjectInputStream(servletCon.getInputStream());
                             v= (Vector)inputStream.readObject();                     
                             imgicon=(ImageIcon)v.get(1);
                             showimg.setIcon(imgicon);
                             this.getContentPane().validate();
                             this.validate();  
                            inputStream.close();                                                        
                         //  repaint();
                 }catch(Exception e){e.printStackTrace();}  and this is at servlet side
        try {       
                     Vector v=new Vector();                    
                     ObjectInputStream inputFromjsp = new ObjectInputStream(request.getInputStream());                                      
                      v = (Vector)inputFromjsp.readObject();                                                                                                          
                      imgicon=(ImageIcon)v.get(0);                     
                      inputFromjsp.close();            
                      System.out.println(imgicon.getDescription());                                      
                      v.remove(0);
                      v.add(1,imgicon);
//sending back to applet
                       response.setContentType("application/octet-stream");
                      ObjectOutputStream oboutstream=new ObjectOutputStream(response.getOutputStream());            
                      oboutstream.writeObject(v);
                      oboutstream.flush();
                      oboutstream.close();
               } catch (Exception e) {e.printStackTrace();}  i really need your help. please let me out of this headche
thanks
Edited by: san_4u on Nov 24, 2007 1:00 PM

Answer 1

BalusC wrote:
san_4u wrote:
how can i made a HttpClient PostMethod using java applets? as i have experience making request using HttpURLConnection.POST method. ok first of all i am going make a search of this only after i will tell. please be onlineOnce again, see link [3] in my first reply of your former topic.
yeah! i got the related topic at http://www.theserverside.com/tt/articles/article.tss?l=HttpClient_FileUpload. please look it, i am reading it right now and expecting to be reliable for me.
well what i got, when request made by html code(stated above) then all the form fields and file data mixed as binary data and available in HttpServletRequest.getinputstream. and at servlet side we have to use a mutipart parser of DiskFileItemFactory class that automatically parse the file data and return a FileItem object cotaing the actual file data,right?.You can also setup the MultipartFilter in your environment and don't >care about it further. Uploaded files will be available as request attributes in the servlet.is the multipartfilter class file available in jar files(that u suggested to add in yours article) so that i can use it directly? one more thing the import org.apache.commons.httpclient package is not available in these jar files, so where can got it from?
one mere question..
i looked somewhere that when we request for a file from webserver using web browser then there is a server that process our request and after retrieving that file from database it sends back as response.
now i confused that, wheather these webservers are like apache tomcat, IBM's webspher etc those processes these request or there is a unique server that always turned on and process all the request?
because, suppose in an orgnisation made it's website using its own server then, in fact, all the time it will not turned on its server or yes it will? and a user can make a search for kind of information about this orgnisation at any time.
hopes, you will have understand my quary, then please let me know the actual process
thanks
Edited by: san_4u on Nov 25, 2007 11:25 AM