servletdemo2chartgenerator.java

在软件开发中用来绘制各种图表的源码

/* -------------------------------
 * ServletDemo2ChartGenerator.java
 * -------------------------------
 * (C) Copyright 2002-2004, by Object Refinery Limited.
 *
 */

package demo;

import java.io.IOException;
import java.io.OutputStream;

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.ChartUtilities;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.data.category.DefaultCategoryDataset;
import org.jfree.data.general.DefaultPieDataset;
import org.jfree.data.time.Day;
import org.jfree.data.time.TimeSeries;
import org.jfree.data.time.TimeSeriesCollection;
import org.jfree.data.xy.XYDataset;
import org.jfree.date.MonthConstants;

/**
 * A servlet that returns one of three charts as a PNG image file.  This servlet is
 * referenced in the HTML generated by ServletDemo2.
 * <P>
 * Three different charts can be generated, controlled by the 'type' parameter.  The possible
 * values are 'pie', 'bar' and 'time' (for time series).
 * <P>
 * This class is described in the JFreeChart Developer Guide.
 */
public class ServletDemo2ChartGenerator extends HttpServlet {

    /**
     * Default constructor.
     */
    public ServletDemo2ChartGenerator() {
        // nothing required
    }

    /**
     * Process a GET request.
     *
     * @param request  the request.
     * @param response  the response.
     *
     * @throws ServletException if there is a servlet related problem.
     * @throws IOException if there is an I/O problem.
     */
    public void doGet(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {

        OutputStream out = response.getOutputStream();
        try {
            String type = request.getParameter("type");
            JFreeChart chart = null;
            if (type.equals("pie")) {
                chart = createPieChart();
            }
            else if (type.equals("bar")) {
                chart = createBarChart();
            }
            else if (type.equals("time")) {
                chart = createTimeSeriesChart();
            }
            if (chart != null) {
                response.setContentType("image/png");
                ChartUtilities.writeChartAsPNG(out, chart, 400, 300);
            }
        }
        catch (Exception e) {
            System.err.println(e.toString());
        }
        finally {
            out.close();
        }

    }

    /**
     * Creates a sample pie chart.
     *
     * @return a pie chart.
     */
    private JFreeChart createPieChart() {

        // create a dataset...
        DefaultPieDataset data = new DefaultPieDataset();
        data.setValue("One", new Double(43.2));
        data.setValue("Two", new Double(10.0));
        data.setValue("Three", new Double(27.5));
        data.setValue("Four", new Double(17.5));
        data.setValue("Five", new Double(11.0));
        data.setValue("Six", new Double(19.4));

        JFreeChart chart = ChartFactory.createPieChart(
            "Pie Chart", data, true, true, false
        );
        return chart;

    }

    /**
     * Creates a sample bar chart.
     *
     * @return a bar chart.
     */
    private JFreeChart createBarChart() {

        DefaultCategoryDataset dataset = new DefaultCategoryDataset();
        dataset.addValue(10.0, "S1", "C1");
        dataset.addValue(4.0, "S1", "C2");
        dataset.addValue(15.0, "S1", "C3");
        dataset.addValue(14.0, "S1", "C4");
        dataset.addValue(-5.0, "S2", "C1");
        dataset.addValue(-7.0, "S2", "C2");
        dataset.addValue(14.0, "S2", "C3");
        dataset.addValue(-3.0, "S2", "C4");
        dataset.addValue(6.0, "S3", "C1");
        dataset.addValue(17.0, "S3", "C2");
        dataset.addValue(-12.0, "S3", "C3");
        dataset.addValue( 7.0, "S3", "C4");
        dataset.addValue(7.0, "S4", "C1");
        dataset.addValue(15.0, "S4", "C2");
        dataset.addValue(11.0, "S4", "C3");
        dataset.addValue(0.0, "S4", "C4");
        dataset.addValue(-8.0, "S5", "C1");
        dataset.addValue(-6.0, "S5", "C2");
        dataset.addValue(10.0, "S5", "C3");
        dataset.addValue(-9.0, "S5", "C4");
        dataset.addValue(9.0, "S6", "C1");
        dataset.addValue(8.0, "S6", "C2");
        dataset.addValue(null, "S6", "C3");
        dataset.addValue(6.0, "S6", "C4");
        dataset.addValue(-10.0, "S7", "C1");
        dataset.addValue(9.0, "S7", "C2");
        dataset.addValue(7.0, "S7", "C3");
        dataset.addValue(7.0, "S7", "C4");
        dataset.addValue(11.0, "S8", "C1");
        dataset.addValue(13.0, "S8", "C2");
        dataset.addValue(9.0, "S8", "C3");
        dataset.addValue(9.0, "S8", "C4");
        dataset.addValue(-3.0, "S9", "C1");
        dataset.addValue(7.0, "S9", "C2");
        dataset.addValue(11.0, "S9", "C3");
        dataset.addValue(-10.0, "S9", "C4");
            
        JFreeChart chart = ChartFactory.createBarChart3D(
            "Bar Chart",
            "Category",
            "Value",
            dataset,
            PlotOrientation.VERTICAL,
            true, 
            true, 
            false
        );
        return chart;

    }

    /**
     * Creates a sample time series chart.
     *
     * @return a time series chart.
     */
    private JFreeChart createTimeSeriesChart() {

        // here we just populate a series with random data...
        TimeSeries series = new TimeSeries("Random Data");
        Day current = new Day(1, MonthConstants.JANUARY, 2001);
        for (int i = 0; i < 100; i++) {
            series.add(current, Math.random() * 100);
            current = (Day) current.next();
        }
        XYDataset data = new TimeSeriesCollection(series);

        JFreeChart chart = ChartFactory.createTimeSeriesChart(
            "Time Series Chart", "Date", "Rate", 
            data, true, true, false
        );
        return chart;

    }

}