Image resizing & conerting to byte[]

Question

I'm working on a servlet. I have an image stored in a database
(jpg or gif), and i need to resize it before sending to browser.
I know how to create an Image from a byte array, and resize it,
but how can i create again a gif/jpg file from the Image object
and transform it again to a byte array to send to client?
Thanks!!

Answer 1

Hm...that was only half the answer...
For jpg encoders, there is one in rt.jar that works, but it requires some manual labor...and starting up the awt event thread which is sort of costly.
Here's an example of how to encode a file to jpg.
(You must include rt.jar in the classpath for it to compile and run)
import com.sun.image.codec.jpeg.*;
import java.io.*;
import java.awt.*;
import javax.swing.*;
import java.awt.image.*;
public class Test extends JFrame
     public Test()
          super("JPG encoder");
          getContentPane().setLayout(new GridLayout(2,1));
          ImageIcon theIcon = new ImageIcon("image.gif");
          int w = theIcon.getIconWidth();
          int h = theIcon.getIconHeight();
          getContentPane().add(new JLabel(theIcon));
          setVisible(true);
          BufferedImage theImage = (BufferedImage)createImage(w, h);
          theImage.createGraphics().drawImage(theIcon.getImage(), 0, 0, Color.black,null);
          setLocation(300,300);
          try
               FileOutputStream theStream = new FileOutputStream("image.jpg");
               JPEGImageEncoder theEncoder = JPEGCodec.createJPEGEncoder(theStream);
               theEncoder.encode(theImage);
               ImageIcon theNewIcon = new ImageIcon("image.jpg");
               getContentPane().add(new JLabel(theNewIcon));
               pack();
          catch (Exception e)
          {e.printStackTrace();}
     public static void main(String[] args)
          new Test();
}You can easily change that FileOutputStream to a ByteArrayOutputStream and then just extract the bytes...