如何在JFreeChart中创建条形图？

Question

我设法创建了一个简单的XYLineChart，但现在我需要用条形图而不是线条来完成。这意味着如果Y值低于零，则条形将被反转。

public static void plotmain(double [] ya, int [] xa) {
    dataset = new XYSeriesCollection();
    XYSeries data = new XYSeries("");

    for (int i = 0 ; i < ya.length ; i++) {
        data.add(xa[i], ya[i]);
    }
    dataset.addSeries(data);
    showGraph();
}

private static void showGraph() {
    final JFreeChart chart = createChart(dataset);
    final ChartPanel chartPanel = new ChartPanel(chart);
    chartPanel.setPreferredSize(new java.awt.Dimension(resx, resy));
    final ApplicationFrame frame = new ApplicationFrame("");
    frame.setContentPane(chartPanel);
    frame.pack();
    frame.setVisible(true);
}

private static JFreeChart createChart(final XYDataset dataset) {
    final JFreeChart chart = ChartFactory.createXYLineChart(
        "", // chart title
        "", // x axis label
        "", // y axis label
        dataset, // data
        PlotOrientation.VERTICAL,
        true, // include legend
        true, // tooltips
        false // urls
    );
    XYPlot plot = (XYPlot) chart.getPlot();
    XYLineAndShapeRenderer renderer = new XYLineAndShapeRenderer();
    renderer.setSeriesLinesVisible(0, true);
    renderer.setSeriesShapesVisible(0, false);
    renderer.setSeriesPaint(0, Color.blue);
    plot.setRenderer(renderer);
    return chart;
}