need help regarding java servlet.

HI all..

I have a html page which contain four text box in which user have 2 fill four integer value.These values will be taken by a servlet and pass to a second servlet which contain code of jfree chart for creation of graph according to user input.The problen is that I am getting only a croos mark instead of getting graph.I do not know where I am doing mistake?:confused:
I have made a folder dynamicpage in webaaps folder of tomcat4.1 which contain webinf folder and my html page.In web-inf 2 folder classes and lib is there and a web-xml file is there.

Let's brake it down.

Can you easily send some piece of info from servlet1 to servlet2?

There are few approaches in serlvet1-to-servlet2 communication but
for security reasons direct call of one servelt2 instance in servlet1
is not recommended.

One approach is to use redirect:

Code:

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  HttpServletResponse  response;
  response.sendRedirect(URL+"servlet-name");

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But better approach is to use RequestDispatcher for this.
Maybe put some Attribute in request of servlet1 and use RequestDispatcher
to send it to servlet2

Code:

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request.setAttribute("AttributeName","This is the Attribute value.");
RequestDispatcher dispatcher =  request.getRequestDispatcher(someUrl);
dispather.forward(request, response); (or redirect instead of forward)

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So can you test this - just simulate all and write in console test values
from request object in both servlets?

Here is some help:

Forwarding and Including Response from other Servlets

regards

Big thanx for your reply!!here is my 2 servlet page.

code of java servlet ChartSetup.java

Code:

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package com.karthik.sample;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class ChartSetup extends HttpServlet {
        public void doGet(HttpServletRequest request, HttpServletResponse response)
                        throws IOException, ServletException {
                String line = request.getParameter("t1");
                String line1 = request.getParameter("t2");
                String line2 = request.getParameter("t3");
                String line3 = request.getParameter("t4");
                double x1 = Double.parseDouble(line);
                double y1 = Double.parseDouble(line1);
                double x2 = Double.parseDouble(line2);
                double y2 = Double.parseDouble(line3);
                request.setAttribute("x1", x1);
                request.setAttribute("y1", y1);
                request.setAttribute("x2", x2);
                request.setAttribute("y2", y2);
                getServletContext().getRequestDispatcher("/ChartGenerator").forward(
                                request, response);
        }
}

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code of chartgenrator

Code:

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package com.karthik.sample;

import java.awt.image.BufferedImage;
import java.io.IOException;

import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.jfree.chart.ChartFactory;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.data.xy.XYDataset;
import org.jfree.data.xy.XYSeries;
import org.jfree.data.xy.XYSeriesCollection;

public class ChartGenerator extends HttpServlet {
        private static final long serialVersionUID = 1L;

        protected void doGet(HttpServletRequest request,
                        HttpServletResponse response) throws ServletException, IOException {
                response.setContentType("image/gif");
                XYSeries series = new XYSeries("Average Weight");
                Double x1 = (Double) request.getAttribute("x1");
                Double y1 = (Double) request.getAttribute("y1");
                Double x2 = (Double) request.getAttribute("x2");
                Double y2 = (Double) request.getAttribute("y2");
                series.add(x1, y1);
                series.add(x2, y2);
                XYDataset xyDataset = new XYSeriesCollection(series);
                JFreeChart chart = ChartFactory.createXYLineChart(
                                "XYLine Chart using JFreeChart", "Age", "Weight", xyDataset,
                                PlotOrientation.VERTICAL, true, true, false);
                BufferedImage bufferedImage = chart.createBufferedImage(500, 500);
                ImageIO.write(bufferedImage, "gif", response.getOutputStream());
        }
}

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