在JFreeChart中如何获得图表上某一点的[x，y]值？

// 导入必要的包
import org.jfree.chart.*;
import org.jfree.chart.entity.*;
import org.jfree.chart.plot.*;
import org.jfree.data.general.*;
import java.awt.*;
import java.awt.event.*;

public class ChartMouseListenerExample {
    public static void main(String[] args) {
        // 创建一个数据集
        DefaultCategoryDataset dataset = new DefaultCategoryDataset();
        dataset.addValue(1.0, "Series 1", "Category 1");
        dataset.addValue(2.0, "Series 1", "Category 2");
        dataset.addValue(3.0, "Series 1", "Category 3");
        
        // 创建一个图表
        JFreeChart chart = ChartFactory.createLineChart(
                "Chart Title", "Category", "Value", dataset,
                PlotOrientation.VERTICAL, true, true, false);
        
        // 创建一个图表面板
        ChartPanel chartPanel = new ChartPanel(chart);
        
        // 添加鼠标事件监听器
        chartPanel.addChartMouseListener(new ChartMouseListener() {
            @Override
            public void chartMouseClicked(ChartMouseEvent event) {
                // 获取图表对象
                JFreeChart chart = event.getChart();
                
                // 获取渲染信息
                ChartRenderingInfo info = chartPanel.getChartRenderingInfo();
                
                // 获取鼠标事件发生的点的坐标
                int mouseX = event.getTrigger().getX();
                int mouseY = event.getTrigger().getY();
                
                // 获取实体集合
                EntityCollection entities = info.getEntityCollection();
                
                // 遍历实体集合，判断事件发生的点是否在数据点的范围内
                for (Object entity : entities.getEntities()) {
                    if (entity instanceof XYItemEntity) {
                        XYItemEntity itemEntity = (XYItemEntity) entity;
                        
                        // 获取数据点的矩形区域
                        Rectangle2D dataArea = info.getPlotInfo().getDataArea();
                        Rectangle2D rect = itemEntity.getArea(dataArea, chart.getXYPlot().getOrientation());
                        
                        // 判断鼠标事件发生的点是否在数据点的范围内
                        if (rect.contains(mouseX, mouseY)) {
                            // 获取数据点的[x，y]值
                            double x = itemEntity.getDataset().getXValue(itemEntity.getSeriesIndex(), itemEntity.getItem());
                            double y = itemEntity.getDataset().getYValue(itemEntity.getSeriesIndex(), itemEntity.getItem());
                            System.out.println("[" + x + ", " + y + "]");
                            break;
                        }
                    }
                }
            }
            
            @Override
            public void chartMouseMoved(ChartMouseEvent event) {
                // 空实现
            }
        });
        
        // 创建一个窗口显示图表
        JFrame frame = new JFrame("Chart Example");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().add(chartPanel);
        frame.setSize(500, 500);
        frame.setVisible(true);
    }
}