如何在java数据库中绘制带有日期的甘特图？

import java.sql.*;
import org.jfree.chart.*;
import org.jfree.chart.plot.*;
import org.jfree.data.gantt.*;
import org.jfree.data.time.*;

public class GanttChartExample {
    public static void main(String[] args) {
        // 连接到数据库
        String url = "jdbc:mysql://localhost:3306/mydatabase";
        String username = "root";
        String password = "password";
        try (Connection conn = DriverManager.getConnection(url, username, password)) {
            // 查询甘特图数据
            String query = "SELECT task_name, start_date, end_date FROM gantt_chart_data";
            try (Statement stmt = conn.createStatement();
                 ResultSet rs = stmt.executeQuery(query)) {
                // 创建甘特图数据集
                TaskSeriesCollection dataset = new TaskSeriesCollection();
                TaskSeries series = new TaskSeries("Tasks");
                
                // 遍历查询结果，添加任务到数据集
                while (rs.next()) {
                    String taskName = rs.getString("task_name");
                    Date startDate = rs.getDate("start_date");
                    Date endDate = rs.getDate("end_date");
                    Task task = new Task(taskName, startDate, endDate);
                    series.add(task);
                }
                
                dataset.add(series);
                
                // 创建甘特图
                JFreeChart chart = ChartFactory.createGanttChart(
                    "Gantt Chart", "Tasks", "Date", dataset);
                
                // 显示甘特图
                ChartFrame frame = new ChartFrame("Gantt Chart", chart);
                frame.pack();
                frame.setVisible(true);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}