使用JavaFX创建一个实时更新的时钟程序

DateFormat currentTime = new SimpleDateFormat("yyyy.MM.dd hh:mm:ss");

import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.layout.BorderPane;
import javafx.scene.text.Font;
import javafx.stage.Stage;
import javafx.animation.KeyFrame;
import javafx.animation.Timeline;
import javafx.util.Duration;

import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;

public class RealTimeClock extends Application {

    @Override
    public void start(Stage primaryStage) {
        // 1. 创建时间标签
        Label timeLabel = new Label();
        timeLabel.setFont(new Font(20));  // 设置字体大小为20

        // 2. 设置时间格式
        DateFormat dateFormat = new SimpleDateFormat("yyyy.MM.dd HH:mm:ss");

        // 3. 创建事件处理器：每秒更新时间
        EventHandler<ActionEvent> eventHandler = e -> {
            String currentTime = dateFormat.format(new Date());
            timeLabel.setText(currentTime);
            System.out.println(currentTime);  // 控制台同步输出
        };

        // 4. 创建 Timeline 动画
        Timeline animation = new Timeline(
            new KeyFrame(Duration.millis(1000), eventHandler)
        );
        animation.setCycleCount(Timeline.INDEFINITE);  // 无限循环
        animation.play();  // 启动动画

        // 5. 布局设置：将时间标签放在右下角
        BorderPane root = new BorderPane();
        root.setPadding(new Insets(20));
        BorderPane.setAlignment(timeLabel, Pos.BOTTOM_RIGHT);
        root.setBottom(timeLabel);

        // 6. 创建场景
        Scene scene = new Scene(root, 400, 300);
        primaryStage.setTitle("JavaFX 实时时钟");
        primaryStage.setScene(scene);
        primaryStage.show();
    }

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

2026.06.13 21:49:00
2026.06.13 21:49:01
2026.06.13 21:49:02
2026.06.13 21:49:03
...

Timeline animation = new Timeline(
    new KeyFrame(Duration.millis(1000), eventHandler)
);

启动 (play)
    ├── 等待 1000ms
    ├── 执行 eventHandler（更新时间）
    ├── 等待 1000ms
    ├── 执行 eventHandler（更新时间）
    └── ...无限循环

import javafx.application.Application;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.layout.HBox;
import javafx.scene.text.Font;
import javafx.scene.text.FontWeight;
import javafx.stage.Stage;
import javafx.animation.KeyFrame;
import javafx.animation.Timeline;
import javafx.util.Duration;

import java.text.SimpleDateFormat;
import java.util.Date;

public class StatusBarClock extends Application {

    private Label timeLabel;
    private Label statusLabel;
    private int seconds = 0;

    @Override
    public void start(Stage primaryStage) {
        // 状态标签
        statusLabel = new Label("系统运行中");
        statusLabel.setFont(Font.font(14));

        // 时间标签
        timeLabel = new Label();
        timeLabel.setFont(Font.font("Consolas", FontWeight.BOLD, 16));

        // 布局
        HBox statusBar = new HBox(20);
        statusBar.setAlignment(Pos.CENTER_RIGHT);
        statusBar.setPadding(new Insets(10, 20, 10, 20));
        statusBar.getChildren().addAll(statusLabel, timeLabel);

        // Timeline：每秒更新
        Timeline timeline = new Timeline(
            new KeyFrame(Duration.seconds(1), e -> update())
        );
        timeline.setCycleCount(Timeline.INDEFINITE);
        timeline.play();

        Scene scene = new Scene(statusBar, 500, 50);
        primaryStage.setTitle("状态栏时钟");
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    private void update() {
        // 更新时间
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        timeLabel.setText(sdf.format(new Date()));

        // 更新运行时长
        seconds++;
        if (seconds % 5 == 0) {
            statusLabel.setText("已运行 " + seconds + " 秒");
        }
    }

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