问个jfreeChart的有关问题，怎么根据面板坐标获取X、Y轴的值

import java.awt.Dimension;import java.awt.Point;import java.awt.geom.Point2D;import java.awt.geom.Rectangle2D;import org.jfree.chart.ChartFactory;import org.jfree.chart.ChartMouseEvent;import org.jfree.chart.ChartMouseListener;import org.jfree.chart.ChartPanel;import org.jfree.chart.ChartRenderingInfo;import org.jfree.chart.JFreeChart;import org.jfree.chart.axis.ValueAxis;import org.jfree.chart.plot.PlotOrientation;import org.jfree.chart.plot.XYPlot;import org.jfree.data.xy.XYDataset;import org.jfree.data.xy.XYSeries;import org.jfree.data.xy.XYSeriesCollection;import org.jfree.ui.ApplicationFrame;import org.jfree.ui.RectangleEdge;import org.jfree.ui.RefineryUtilities;public class MouseListenerDemo extends ApplicationFrame implements ChartMouseListener{    /**     *      */    private static final long serialVersionUID = 1L;    private JFreeChart chart;    private ChartPanel chartPanel;    public MouseListenerDemo(String paramString){        super(paramString);        String applicationTitle = "Mouse Listener Demo";        XYDataset xyDataset = createDataset();        this.chart = ChartFactory.createXYLineChart(applicationTitle, "X", "Y", xyDataset,                        PlotOrientation.VERTICAL, true, true, false);        this.chartPanel = new ChartPanel(this.chart);        this.chartPanel.setPreferredSize(new Dimension(700, 450));        this.chartPanel.setMouseZoomable(true, false);        this.chartPanel.addChartMouseListener(this);        setContentPane(this.chartPanel);    }    public XYDataset createDataset(){        XYSeries xySeries = new XYSeries("Series 1");        xySeries.add(12.0D, 10.0D);        xySeries.add(13.0D, 15.0D);        xySeries.add(14.0D, 16.0D);        xySeries.add(15.5D, 17.0D);        xySeries.add(17.0D, 20.0D);        xySeries.add(18.0D, 18.0D);        xySeries.add(19.0D, 16.0D);        xySeries.add(20.0D, 15.0D);        XYSeriesCollection xySeriesCollection = new XYSeriesCollection();        xySeriesCollection.addSeries(xySeries);        return xySeriesCollection;    }    public void chartMouseClicked(ChartMouseEvent paramChartMouseEvent){        int xPos = paramChartMouseEvent.getTrigger().getX();        int yPos = paramChartMouseEvent.getTrigger().getY();        System.out.println("x = " + xPos + ", y = " + yPos);        Point2D point2D = this.chartPanel.translateScreenToJava2D(new Point(xPos, yPos));        XYPlot xyPlot = (XYPlot)this.chart.getPlot();        ChartRenderingInfo chartRenderingInfo = this.chartPanel.getChartRenderingInfo();        Rectangle2D rectangle2D = chartRenderingInfo.getPlotInfo().getDataArea();        ValueAxis valueAxis1 = xyPlot.getDomainAxis();        RectangleEdge rectangleEdge1 = xyPlot.getDomainAxisEdge();        ValueAxis valueAxis2 = xyPlot.getRangeAxis();        RectangleEdge rectangleEdge2 = xyPlot.getRangeAxisEdge();        double d1 = valueAxis1.java2DToValue(point2D.getX(), rectangle2D, rectangleEdge1);        double d2 = valueAxis2.java2DToValue(point2D.getY(), rectangle2D, rectangleEdge2);        System.out.println("Chart: x = " + d1 + ", y = " + d2);    }    public void chartMouseMoved(ChartMouseEvent paramChartMouseEvent){        }    public static void main(String[] paramArrayOfString){        MouseListenerDemo localMouseListenerDemo = new MouseListenerDemo("JFreeChart: MouseListenerDemo.java");        localMouseListenerDemo.pack();        RefineryUtilities.centerFrameOnScreen(localMouseListenerDemo);        localMouseListenerDemo.setVisible(true);    }}