JFreeChart:在鼠标单击时获取数据源值

import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartMouseEvent;
import org.jfree.chart.ChartMouseListener;
import org.jfree.chart.ChartPanel;
import org.jfree.chart.JFreeChart;
import org.jfree.data.category.DefaultCategoryDataset;
import org.jfree.ui.ApplicationFrame;

import java.awt.*;
import java.awt.event.MouseEvent;

public class JFreeChartExample extends ApplicationFrame {

    public JFreeChartExample(String title) {
        super(title);
        // 创建数据集
        DefaultCategoryDataset dataset = new DefaultCategoryDataset();
        dataset.addValue(1, "Series 1", "Category 1");
        dataset.addValue(2, "Series 1", "Category 2");
        dataset.addValue(3, "Series 1", "Category 3");

        // 创建图表
        JFreeChart chart = ChartFactory.createBarChart(
                "Example Chart", "Category", "Value", dataset);

        // 创建图表面板
        ChartPanel chartPanel = new ChartPanel(chart);
        chartPanel.setPreferredSize(new Dimension(500, 300));

        // 添加鼠标点击事件监听器
        chartPanel.addChartMouseListener(new ChartMouseListener() {
            @Override
            public void chartMouseClicked(ChartMouseEvent event) {
                // 获取鼠标点击的坐标
                int x = event.getTrigger().getX();
                int y = event.getTrigger().getY();

                // 获取与坐标相关联的实体对象
                ChartRenderingInfo info = chartPanel.getChartRenderingInfo();
                EntityCollection entities = info.getEntityCollection();
                ChartEntity entity = entities.getEntity(x, y);

                // 判断实体对象类型并获取数据源值
                if (entity instanceof CategoryItemEntity) {
                    CategoryItemEntity itemEntity = (CategoryItemEntity) entity;
                    Comparable rowKey = itemEntity.getRowKey();
                    Comparable columnKey = itemEntity.getColumnKey();
                    Number value = dataset.getValue(rowKey, columnKey);
                    System.out.println("Clicked value: " + value);
                }
            }

            @Override
            public void chartMouseMoved(ChartMouseEvent event) {
                // Do nothing
            }
        });

        setContentPane(chartPanel);
    }

    public static void main(String[] args) {
        JFreeChartExample example = new JFreeChartExample("JFreeChart Example");
        example.pack();
        example.setVisible(true);
    }
}