Why do my file is stored and has the correct dimension but I cannot open it

Question

hi,
I want to store an image from an inputStream to my harddisk. The created file (image) has the same dimensions of the original image (8kb), but I cannot open it with photoshop or other image editors. Something is wrong in the data... can you give me some tips ?
thanks
File outputfile = new File("/Library/Tomcat/webapps/ROOT/WEB-INF/classes/saved2.png");
          try {
               //File f=new File("outFile.java");
               //InputStream inputStream= new FileInputStream("InputStreamToFile.java");
               OutputStream out=new FileOutputStream(outputfile);
               byte buf[]=new byte[1024];
               int len;
               while((len=inputStream.read(buf))>0)
                    out.write(buf,0,len);
               out.close();
               inputStream.close();
               System.out.println("\nFile is created");
          catch (IOException e){
          }

Answer 1

I've solved it with this code:
InputStream inputStream = req.getInputStream();
               BufferedImage img = ImageIO.read(inputStream);
               File outputfile = new File("/Library/Tomcat/webapps/ROOT/WEB-INF/classes/saved2.png");
               //storing the image to file system.
               if (outputfile.isDirectory()) {
                    ImageIO.write(img, "png", outputfile);
               } else {
                    outputfile.mkdirs();
                    ImageIO.write(img, "png", outputfile);
          } catch (Exception e) {
               System.out.println(e.getMessage());
          }