使用JFreeChart为两个系列设置不同的y轴

Question

我正在使用JFreeChart使用折线图绘制两个数据系列(XYSeries).复杂因素是其中一个数据系列的y值通常远高于我的第二个数据系列的y值(假设第一个系列的y值大小为数百万的数量级,而第二系列具有数百个数量级的y值.我的第一个数据集中存在高值会导致绘图的范围使得我的第二个数据集的y值不再可理解.

在绘图中添加第二个y轴,这样我的数据系列都使用自己的y轴,可以解决这个问题.有谁知道如何用JFreeChart做到这一点？

当前完整性代码:

XYSeriesCollection dataset = new XYSeriesCollection();
XYSeries series1 = new XYSeries("series1");
XYSeries series2 = new XYSeries("series2");

// Here is my code to fill series1 and series2 with data    

dataset.addSeries(series1);
dataset.addSeries(series2);

JFreeChart chart = ChartFactory.createXYLineChart(
    "title", "x-axis title", "y-axis title", dataset, PlotOrientation.VERTICAL, true, true, false
);
chart.getXYPlot().setRenderer(new XYSplineRenderer());

Answer 1

您可以手动创建JFreeChart对象,而不是使用ChartFactory.首先生成数据集和Plot,将每个数据集设置为索引.然后,您可以使用必要的轴和渲染器自定义绘图.这是一个使用虚拟数据的示例,该数据具有两个数据集,每个数据集具有不同的y值:

    //create the series - add some dummy data
    XYSeries series1 = new XYSeries("series1");
    XYSeries series2 = new XYSeries("series2");
    series1.add(1000, 1000);
    series1.add(1150, 1150);
    series1.add(1250, 1250);

    series2.add(1000, 111250);
    series2.add(1150, 211250);
    series2.add(1250, 311250);

    //create the datasets
    XYSeriesCollection dataset1 = new XYSeriesCollection();
    XYSeriesCollection dataset2 = new XYSeriesCollection();
    dataset1.addSeries(series1);
    dataset2.addSeries(series2);

    //construct the plot
    XYPlot plot = new XYPlot();
    plot.setDataset(0, dataset1);
    plot.setDataset(1, dataset2);

    //customize the plot with renderers and axis
    plot.setRenderer(0, new XYSplineRenderer());//use default fill paint for first series
    XYSplineRenderer splinerenderer = new XYSplineRenderer();
    splinerenderer.setSeriesFillPaint(0, Color.BLUE);
    plot.setRenderer(1, splinerenderer);
    plot.setRangeAxis(0, new NumberAxis("Series 1"));
    plot.setRangeAxis(1, new NumberAxis("Series 2"));
    plot.setDomainAxis(new NumberAxis("X Axis"));

    //Map the data to the appropriate axis
    plot.mapDatasetToRangeAxis(0, 0);
    plot.mapDatasetToRangeAxis(1, 1);   

    //generate the chart
    JFreeChart chart = new JFreeChart("MyPlot", getFont(), plot, true);
    chart.setBackgroundPaint(Color.WHITE);
    JPanel chartPanel = new ChartPanel(chart);