Form flooding protection

[Aymeric Levaux]

I'm looking for an API that generates image with a random number to display it in a form to check that a real user is filling this form (not a flooder)
Does any body knows about such an API (may be a custom tag ) ?

Thank You !

[Pavel Cherkashin]

Hello, It looks like you should implement it yourself.
I think these passages of code will help you:
The servlet code (in doGet method):

  
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;
. . . 
response.setContentType("image/jpeg");
// see getImage below
BufferedImage image = getImage(55); 
ServletOutputStream sos = response.getOutputStream();
JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(sos);
encoder.encode(image);

The getImage code - it generates BufferedImage,
which shows the fascia of percents passed in parameters
you can draw there digits, text, and other info,
which will be concerned with Session

private BufferedImage getImage(int value) throws IOException {
if (value <= 0) {
value = 0;
} else if (value >= 100) {
value = 100;
}
    int width = 200;
    int height = 20;
    
    int delimiter = (width*value)/100;
    
    // Create a buffered image that supports transparency
    BufferedImage bimage = new BufferedImage(
    width, height, BufferedImage.TYPE_INT_RGB);
    Graphics2D g2d = bimage.createGraphics();
    // Draw on the image
    g2d.setColor(Color.BLACK);
    g2d.draw(new Rectangle2D.Float(0, 0, width-1, height-1));
    g2d.setColor(Color.WHITE);
    g2d.fill(new Rectangle2D.Float(1, 1, width-2, height-2));
    g2d.setColor(Color.RED);
    g2d.fill(new Rectangle2D.Float(1, 1, delimiter-2, height-2));
    g2d.dispose();
    
return bimage;
}  

[David O'Meara]

For those coming in late, there is also a response in a (closed) duplicate thread here.