How to reduce image file size in java

Question

I want to reduce image file size of an uploaded image before saving it into server (to reduce loading time). how can I do it using java?

Answer 1

This kind of question has been answered quite a few times on this site. I suggest you check out How to resize the original image into a common size of image in Java? or search for java image resize on this site.

Answer 2

May this following code help you it will resize and keep quality of image.

protected void doPost(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {
        boolean isMultipart = ServletFileUpload.isMultipartContent(request);
             if (!isMultipart) {
             } else {
                FileItemFactory factory = new DiskFileItemFactory();
                ServletFileUpload upload = new ServletFileUpload(factory);
                List items = null;
                try {
                     items = upload.parseRequest(request);
                } catch (FileUploadException e) {
                     System.out.println("Unable to load image" +  e.getMessage());}
                Iterator itr = items.iterator();
                while(itr.hasNext()) {
                     System.out.println(items.size());
                       FileItem item = (FileItem) itr.next();
                       if (!item.isFormField()) {
                          try {
                                 int size = 200;// size of the new image.
                                 //take the file as inputstream.
                                 InputStream imageStream = item.getInputStream();
                                 //read the image as a BufferedImage.
                                 BufferedImage image = javax.imageio.ImageIO.read(imageStream); 
                                 //cal the sacleImage method.
                                 BufferedImage newImage = scaleImage(image, size);
                                 String path = getServletContext().getRealPath("/image");
                                 //write file.
                                 File file = new File(path, "testimage.jpg");
                                 ImageIO.write(newImage, "JPG", file);
                          } catch (Exception e) {
                               System.out.println("Unable to save the image" + e.getMessage());
                               //System.out.println(path);
                  }//if
                }//iter
        }
    private BufferedImage scaleImage(BufferedImage bufferedImage, int size) {
         double boundSize = size;
            int origWidth = bufferedImage.getWidth();
            int origHeight = bufferedImage.getHeight();
            double scale;
            if (origHeight > origWidth)
                scale = boundSize / origHeight;
            else
                scale = boundSize / origWidth;
             //* Don't scale up small images.
            if (scale > 1.0)
                return (bufferedImage);
            int scaledWidth = (int) (scale * origWidth);
            int scaledHeight = (int) (scale * origHeight);
            Image scaledImage = bufferedImage.getScaledInstance(scaledWidth, scaledHeight, Image.SCALE_SMOOTH);
            // new ImageIcon(image); // load image
            // scaledWidth = scaledImage.getWidth(null);
            // scaledHeight = scaledImage.getHeight(null);
            BufferedImage scaledBI = new BufferedImage(scaledWidth, scaledHeight, BufferedImage.TYPE_INT_RGB);
            Graphics2D g = scaledBI.createGraphics();
                 g.setRenderingHint(RenderingHints.KEY_INTERPOLATION,RenderingHints.VALUE_INTERPOLATION_BILINEAR);
            g.drawImage(scaledImage, 0, 0, null);
            g.dispose();
            return (scaledBI);
    }