将对象按日期分组以放入图形JavaFX中

import javafx.application.Application;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.scene.Scene;
import javafx.scene.chart.LineChart;
import javafx.scene.chart.NumberAxis;
import javafx.scene.chart.XYChart;
import javafx.stage.Stage;

import java.time.LocalDate;
import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

public class GroupObjectsByDate extends Application {

    public static void main(String[] args) {
        launch(args);
    }

    @Override
    public void start(Stage primaryStage) {
        // 创建图表的横轴和纵轴
        final NumberAxis xAxis = new NumberAxis();
        final NumberAxis yAxis = new NumberAxis();

        // 创建折线图
        final LineChart<Number, Number> lineChart = new LineChart<>(xAxis, yAxis);
        lineChart.setTitle("Objects Grouped by Date");

        // 创建对象列表
        List<DataObject> dataObjects = Arrays.asList(
                new DataObject("Object 1", LocalDate.of(2022, 1, 1), 10),
                new DataObject("Object 2", LocalDate.of(2022, 1, 1), 15),
                new DataObject("Object 3", LocalDate.of(2022, 1, 2), 20),
                new DataObject("Object 4", LocalDate.of(2022, 1, 2), 25),
                new DataObject("Object 5", LocalDate.of(2022, 1, 3), 30)
        );

        // 将对象按日期分组
        Map<LocalDate, List<DataObject>> groupedData = dataObjects.stream()
                .collect(Collectors.groupingBy(DataObject::getDate));

        // 创建图表数据集
        ObservableList<XYChart.Series<Number, Number>> chartData = FXCollections.observableArrayList();

        // 遍历分组后的数据，创建图表系列
        for (Map.Entry<LocalDate, List<DataObject>> entry : groupedData.entrySet()) {
            LocalDate date = entry.getKey();
            List<DataObject> objects = entry.getValue();

            XYChart.Series<Number, Number> series = new XYChart.Series<>();
            series.setName(date.toString());

            // 将对象数据添加到系列中
            for (DataObject object : objects) {
                series.getData().add(new XYChart.Data<>(object.getValue(), object.getQuantity()));
            }

            chartData.add(series);
        }

        // 设置图表数据
        lineChart.setData(chartData);

        // 创建场景并显示图表
        Scene scene = new Scene(lineChart, 800, 600);
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    // 示例数据对象
    private static class DataObject {
        private final String name;
        private final LocalDate date;
        private final int quantity;

        public DataObject(String name, LocalDate date, int quantity) {
            this.name = name;
            this.date = date;
            this.quantity = quantity;
        }

        public String getName() {
            return name;
        }

        public LocalDate getDate() {
            return date;
        }

        public int getQuantity() {
            return quantity;
        }
    }
}