How to reduce image file size in java

I want to reduce ima开发者_StackOverflow中文版ge file size of an uploaded image before saving it into server (to reduce loading time). how can I do it using java?

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.

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);
    }

/*
 * This will get an image file and returns a byte array resized by the given value.
 */
package tajneed;

import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.File;
import javax.imageio.ImageIO;
import org.imgscalr.Scalr;

public class ImageResizer {

    public static byte[] resize(File icon) {
        try {
           BufferedImage originalImage = ImageIO.read(icon);

           originalImage= Scalr.resize(originalImage, Scalr.Method.QUALITY, Scalr.Mode.FIT_EXACT, 128, 153);
            //To save with original ratio uncomment next line and comment the above.
            //originalImage= Scalr.resize(originalImage, 153, 128);
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            ImageIO.write(originalImage, "jpg", baos);
            baos.flush();
            byte[] imageInByte = baos.toByteArray();
            baos.close();
            return imageInByte;
        } catch (Exception e) {
            return null;
        }


    }
}

Use img4java to reduce the file size of your image.

public static void main(String[] args) throws IOException, InterruptedException, IM4JavaException {
     IMOperation op = new IMOperation();
     //op.resize(500, 500, '>');
     //op.quality(85.0); // jpeg quality (%)
     op.strip(); 
     op.interlace("Plane");
     op.define("jpeg:extent=5kb");
     op.addImage("/home/j/Scrivania/originale.jpg"); // original file
     op.addImage("/home/j/Scrivania/nuova_m.jpg"); // destination
     
     ConvertCmd convert = new ConvertCmd();
     convert.run(op);
}