com.crunchify.jsp.servlet.BarServlet.java Source code

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Here is the source code for com.crunchify.jsp.servlet.BarServlet.java

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package com.crunchify.jsp.servlet;

import java.awt.Color;
import java.awt.Paint;
import java.io.IOException;
import java.io.OutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartUtilities;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.axis.NumberAxis;
import org.jfree.chart.axis.ValueAxis;
import org.jfree.chart.labels.ItemLabelAnchor;
import org.jfree.chart.labels.ItemLabelPosition;
import org.jfree.chart.plot.CategoryPlot;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.chart.renderer.category.CategoryItemRenderer;
import org.jfree.data.category.DefaultCategoryDataset;
import org.jfree.ui.TextAnchor;

public class BarServlet extends HttpServlet {

    private static final long serialVersionUID = 1L;

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException {
        response.setContentType("image/png");
        OutputStream outputStream = response.getOutputStream();
        JFreeChart chart = getChart();
        int width = 500;
        int height = 350;
        ChartUtilities.writeChartAsPNG(outputStream, chart, width, height);

    }

    public JFreeChart getChart() {

        DefaultCategoryDataset dataset = new DefaultCategoryDataset();
        dataset.addValue(15, "1", "451");
        dataset.addValue(12, "1", "851");
        dataset.addValue(10, "2", "362");
        dataset.addValue(5, "2", "142");

        JFreeChart chart = ChartFactory.createBarChart("Bar Chart Demo 3", // chart title
                "Category", // domain axis label
                "Value", // range axis label
                dataset, // data
                PlotOrientation.VERTICAL, // the plot orientation
                false, // include legend
                true, false);

        chart.setBackgroundPaint(Color.lightGray);

        // get a reference to the plot for further customisation...
        CategoryPlot plot = chart.getCategoryPlot();
        plot.setNoDataMessage("NO DATA!");

        CategoryItemRenderer renderer = new CustomRenderer(new Paint[] { Color.red, Color.blue, Color.green,
                Color.yellow, Color.orange, Color.cyan, Color.magenta, Color.blue });

        renderer.setItemLabelsVisible(true);
        ItemLabelPosition p = new ItemLabelPosition(ItemLabelAnchor.CENTER, TextAnchor.CENTER, TextAnchor.CENTER,
                45.0);
        renderer.setPositiveItemLabelPosition(p);
        plot.setRenderer(renderer);

        // change the margin at the top of the range axis...
        ValueAxis rangeAxis = plot.getRangeAxis();
        rangeAxis.setStandardTickUnits(NumberAxis.createIntegerTickUnits());
        rangeAxis.setLowerMargin(0.15);
        rangeAxis.setUpperMargin(0.15);

        return chart;

    }

}