I added the method
public long getLastModified(HttpServletRequest req)
{
return (new Date()).getTime() / 1000 * 1000;
}
to the class but the behaviour is same. Any comments ?
I was xpecting that the browser will get a different return from
getLastModified() every time the servlet is invoked. So the server will
generate new random numbers and thus a new polygon.
-----Original Message-----
From: Kumar Sameer [mailto:[EMAIL PROTECTED]]
Sent: 20 March 2002 09:57
To: [EMAIL PROTECTED]
Subject: When does a servlet reloads/recalculates ?
Hi ! I copied,compiled and ran the code(Please see the attached mail from a
different thread) and wow !! got a realy intresting Image !!!!
But i was xpecting that on each subsequent invocation the image will change
as the code uses random no. But the image remains the same. Maybe because
there is no getLastModified(HttpServletRequest) which may have somehow told
the browser to reload the servlet and create a new image. Am i right ?
Note : If I close and restart the browser, the image changes
Any comments ?
-----Original Message-----
From: ���� �������� [mailto:[EMAIL PROTECTED]]
Sent: 20 March 2002 08:53
To: [EMAIL PROTECTED]
Subject: Re: Dynamic images and graphs using servlets
V> Does anybody have a good article/source as how to create dynamic
V> images/graphs using servlets.
try this example
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.awt.*;
import java.awt.image.*;
import com.sun.image.codec.jpeg.*;
import java.util.*;
public class MakeImage extends HttpServlet {
public void doGet(
HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("image/jpeg");
// Create image
int width=200, height=200;
BufferedImage image = new BufferedImage(
width, height, BufferedImage.TYPE_INT_RGB);
// Get drawing context
Graphics g = image.getGraphics();
// Fill background
g.setColor(Color.white);
g.fillRect(0, 0, width, height);
// Create random polygon
Polygon poly = new Polygon();
Random random = new Random();
for (int i=0; i < 20; i++) {
poly.addPoint(random.nextInt(width),
random.nextInt(height));
}
// Fill polygon
g.setColor(Color.cyan);
g.fillPolygon(poly);
// Dispose context
g.dispose();
// Send back image
ServletOutputStream sos =
response.getOutputStream();
JPEGImageEncoder encoder =
JPEGCodec.createJPEGEncoder(sos);
encoder.encode(image);
}
}
Delivering Dynamic Images from JavaServer PagesTM (JSPTM) Technology.
http://java.sun.com/jdc/JDCTechTips/2001/tt0821.html
--
Best regards,
Yuriy
___________________________________________________________________________
To unsubscribe, send email to [EMAIL PROTECTED] and include in the body
of the message "signoff SERVLET-INTEREST".
Archives: http://archives.java.sun.com/archives/servlet-interest.html
Resources: http://java.sun.com/products/servlet/external-resources.html
LISTSERV Help: http://www.lsoft.com/manuals/user/user.html
___________________________________________________________________________
To unsubscribe, send email to [EMAIL PROTECTED] and include in the body
of the message "signoff SERVLET-INTEREST".
Archives: http://archives.java.sun.com/archives/servlet-interest.html
Resources: http://java.sun.com/products/servlet/external-resources.html
LISTSERV Help: http://www.lsoft.com/manuals/user/user.html
___________________________________________________________________________
To unsubscribe, send email to [EMAIL PROTECTED] and include in the body
of the message "signoff SERVLET-INTEREST".
Archives: http://archives.java.sun.com/archives/servlet-interest.html
Resources: http://java.sun.com/products/servlet/external-resources.html
LISTSERV Help: http://www.lsoft.com/manuals/user/user.html
