Hi,
I was also playing with the same thing. GifEncoder has a peculiar
problem, this class extends another class ImageEncoder, therefore, when I
run the servlet, the browser always shows "NoClassDefError" , something
like that for ImageEnocder class, whereas I placed the both ImageEncoder
and GifEncoder class in the same directory (C:\jdk1.3\jre\classes) where
they should be placed so that Java compiler can use the compiled classes.
I have heard this DREADED problem from many users and I placed this
problem in Java Servlet discussion forum.No one could give me the answer.
If you want to convert a graphics object so that the browser can
interpret that, you can go with either GIF or JPEG image.I spent my time
playing with GIF image but I get that DREADED error message.Then, I
switched to converting the image to JPEG image using Java package.It
works fine.
I am giving u one simple programe which draws two lines and converts it
in JPEG image and the browser can interpret that one.
Hope it helps.
/************************
* A. S. M Rokanuzzaman *
* Atmospheric Science *
* Archive programme *
* ARM database *
************************/
import java.awt.event.*;
import javax.swing.*;
import java.awt.geom.*;
import java.awt.image.*;
import java.io.*;
import javax. servlet.*;
import javax. servlet. http.*;
import java.util.*;
import java. sql.*;
import java.awt.*;
import com.sun.image.codec.jpeg.*;
//import Acme.JPM.Encoders.ImageEncoder;
//import Acme.JPM.Encoders.GifEncoder;
//import com.jrefinery.chart.*;
public class oreilly extends HttpServlet{
private Statement stm = null;
private Connection con = null;
private String URL = "jdbc:odbc:ARM";
PrintWriter out ;
String paramValue="";
double xval[] = {11.2,32.9,41.5,61.5,45.6,67.8};
double yval[] = {21.1,21.4,31.5,41.5,56.7,78.9};
double zval[] = {11.1,11.4,21.5,31.5,46.7,58.9};
public void init(ServletConfig config)
throws ServletException
{
super.init(config);
try{
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
con = DriverManager.getConnection(URL,"","");
}//end try block
catch(Exception e){
e.printStackTrace();
con = null;
}//end catch block
} // end init method
public void doGet(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException
{
//here all return values from HTML forms will be declared.
response.setContentType("image/jpeg");
ServletOutputStream out = response.getOutputStream();
BufferedImage image = new BufferedImage(100,100,
BufferedImage.TYPE_INT_RGB);
Graphics g = image.getGraphics();
g.setColor(Color.lightGray);
g.fillRect(0, 0, 100, 100);
Graphics2D g1 = (Graphics2D)g;
System.out.println("\n" + xval.length + "\n");
for(int i = 0; i<xval.length-1; i++){
g1.setPaint(Color.red);
g1.draw(new Line2D.Double(xval[i]+20,yval[i]+20,xval[i+1]+20,yval[i+1]+20));
g1.draw(new Line2D.Double(xval[i]+20,zval[i]+20,xval[i+1]+20,zval[i+1]+20));
}
JPEGImageEncoder encoder =JPEGCodec.createJPEGEncoder(out);
encoder.encode(image);
out.close();
}
//Process the HTTP Post request
public void doPost(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
doGet(request,response);
}
//Get Servlet information
public String getServletInfo() {
return "JPEGServlet Information";
}
}
*************************
* *
* A.S.M. Rokanuzzaman *
* Computer Science *
* UND *
* Phone:701-777-9352 *
* *
*************************
On Fri, 15 Jun 2001, Yuvaraj Mani wrote:
> I think Jason hunters's Java Servlet Programming has addressed your
> requirement.
> Just visit this link ad see if it suits what you need.
> http://www.servlets.com/jservlet2/examples/ch06/index.html#ex06_08
> Yuvaraj Mani
>
>
>
> -----Original Message-----
> From: A mailing list for discussion about Sun Microsystem's Java Servlet
> API Technology. [mailto:[EMAIL PROTECTED]]On Behalf Of
> Michael Weller
> Sent: Friday, June 15, 2001 8:49 AM
> To: [EMAIL PROTECTED]
> Subject: [off-topic] create BufferedImage from Graphics
>
>
> Hello everybody!
>
> I want to write a servlet that create a BufferedImage object gets the
> Graphics object from it, draws some some stuff on it and finally prints out
> a gif-image created from that Graphics object.
> I think this is a quite basic question but didn't find a solution in the
> archives at java.sun.com or in the java tutorial.
> How do get a Image or an ImageProducer from a Graphics object (I'm working
> with Acme.JPM.Encoders.GifEncoder to convert the Image to a gif) ?
>
> Thanks in advance.
>
> Michael Weller
>
> ___________________________________________________________________________
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