java - 我的 x Axis 整数值以 "19:00:00."为前缀

Question

我是 jFreeChart 的新手。我正在尝试运行下载中提供的示例代码。它运行良好。我想在 x Axis 上显示整数值。我更改了程序以使用 NumberAxis 而不是 DateAxis。但是，当我生成图表时，它显示我的整数 x 值，前缀为“19:00:00”。 (应该是 5, 10，但它显示 19:00:00.005, 19:00:00.010)。我在这里做错了什么？

import java.awt.Color;
import java.text.SimpleDateFormat;
import java.io.File;
import javax.swing.JPanel;

import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartPanel;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.StandardChartTheme;
import org.jfree.chart.axis.DateAxis;
import org.jfree.chart.axis.NumberAxis;
import org.jfree.chart.plot.XYPlot;
import org.jfree.chart.renderer.xy.XYItemRenderer;
import org.jfree.chart.renderer.xy.XYLineAndShapeRenderer;
import org.jfree.data.time.Month;
import org.jfree.data.xy.XYSeries;
import org.jfree.data.xy.XYSeriesCollection;
import org.jfree.data.xy.XYDataset;
import org.jfree.ui.ApplicationFrame;
import org.jfree.ui.RectangleInsets;
import org.jfree.ui.RefineryUtilities;
import org.jfree.chart.ChartUtilities;

/**
 * An example of a time series chart.  For the most part, default settings are
 * used, except that the renderer is modified to show filled shapes (as well as
 * lines) at each data point.
 */
public class PlotExample3 extends ApplicationFrame {

    private static final long serialVersionUID = 1L;

    {
        // set a theme using the new shadow generator feature available in
        // 1.0.14 - for backwards compatibility it is not enabled by default
        ChartFactory.setChartTheme(new StandardChartTheme("JFree/Shadow",
                true));
    }

    /**
     * A demonstration application showing how to create a simple time series
     * chart.  This example uses monthly data.
     *
     * @param title  the frame title.
     */
    public PlotExample3(String title) {
        super(title);
        ChartPanel chartPanel = (ChartPanel) createDemoPanel();
        chartPanel.setPreferredSize(new java.awt.Dimension(500, 270));
        setContentPane(chartPanel);
    }

    /**
     * Creates a chart.
     *
     * @param dataset  a dataset.
     *
     * @return A chart.
     */
    private static JFreeChart createChart(XYDataset dataset) {

        JFreeChart chart = ChartFactory.createTimeSeriesChart(
            "Test",  // title
            "X",             // x-axis label
            "Y",   // y-axis label
            dataset,            // data
            true,               // create legend?
            true,               // generate tooltips?
            false               // generate URLs?
        );

        chart.setBackgroundPaint(Color.white);

        final XYPlot plot = chart.getXYPlot();
        plot.setBackgroundPaint(Color.lightGray);
    //    plot.setAxisOffset(new Spacer(Spacer.ABSOLUTE, 5.0, 5.0, 5.0, 5.0));
        plot.setDomainGridlinePaint(Color.white);
        plot.setRangeGridlinePaint(Color.white);

        final XYLineAndShapeRenderer renderer = new XYLineAndShapeRenderer();
        renderer.setSeriesLinesVisible(1, false);
        renderer.setSeriesShapesVisible(1, false);
        plot.setRenderer(renderer);

        // change the auto tick unit selection to integer units only...
        final NumberAxis rangeAxis = (NumberAxis) plot.getRangeAxis();
        rangeAxis.setStandardTickUnits(NumberAxis.createIntegerTickUnits());

       return chart;
    }

    /**
     * Creates a dataset, consisting of two series of monthly data.
     *
     * @return The dataset.
     */
    private static XYDataset createDataset() {

        XYSeries s1 = new XYSeries("Test");
        s1.add(1, 181.8);
        s1.add(2, 167.3);
        s1.add(3, 153.8);
        s1.add(4, 167.6);
        s1.add(5, 158.8);
        s1.add(7, 148.3);
        s1.add(8, 153.9);
        s1.add(9, 142.7);
        s1.add(10,123.2);
        s1.add(11,131.8);
        s1.add(12,139.6);


        // ******************************************************************
        //  More than 150 demo applications are included with the JFreeChart
        //  Developer Guide...for more information, see:
        //
        //  >   http://www.object-refinery.com/jfreechart/guide.html
        //
        // ******************************************************************

        XYSeriesCollection dataset = new XYSeriesCollection();
        dataset.addSeries(s1);        

        return dataset;

    }

    /**
     * Creates a panel for the demo (used by SuperDemo.java).
     *
     * @return A panel.
     */
    public static JPanel createDemoPanel() {
        JFreeChart chart = createChart(createDataset());


        ChartPanel panel = new ChartPanel(chart);

        try {
            ChartUtilities.saveChartAsPNG(new File("C:/Users/pb/Pictures/MyChart.png"),chart,1000,1000);
        } catch(Exception e) {
            System.err.println(e.getMessage());
        }
        panel.setFillZoomRectangle(true);
        panel.setMouseWheelEnabled(true);
        return panel;
    }

    /**
     * Starting point for the demonstration application.
     *
     * @param args  ignored.
     */
    public static void main(String[] args) {

        PlotExample3 demo = new PlotExample3("Time Series Chart Demo 1");
        demo.pack();
        RefineryUtilities.centerFrameOnScreen(demo);
        demo.setVisible(true);

    }

}

Answer 1

ChartFactory.createTimeSeriesChart() 创建一个图表，其中 x Axis 为 DateAxis，y Axis 为 NumberAxis。此方法的 Javadoc 甚至说:“时间序列图表是一个 XYPlot，其中 x Axis 为 DateAxis，y Axis 为 NumberAxis。”

您应该尝试 ChartFactory.createXYLineChart()，它将为您提供 x Axis 的 NumberAxis。