用java写一个消息提醒弹窗，且窗口自适应，窗口透明化，文字在桌面滚动

可以使用 Java Swing 库来实现一个消息提醒弹窗，以下是一个简单的实现示例：

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.GraphicsEnvironment;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.Timer;

public class MessagePopup extends JFrame {
    private static final long serialVersionUID = 1L;
    private static final int POPUP_WIDTH = 300;
    private static final int POPUP_HEIGHT = 100;
    private static final int POPUP_DURATION = 5000; // in milliseconds
    private static final int SCROLL_SPEED = 2; // in pixels per frame
    private static final Font MESSAGE_FONT = new Font("Arial", Font.BOLD, 16);
    private static final Color MESSAGE_COLOR = Color.WHITE;
    private static final Color BACKGROUND_COLOR = new Color(0, 0, 0, 200);
    private static final Timer TIMER = new Timer(POPUP_DURATION, new ActionListener() {
        @Override
        public void actionPerformed(ActionEvent e) {
            MessagePopup.this.dispose();
        }
    });
    private final JLabel messageLabel;

    public MessagePopup(String message) {
        super();
        setUndecorated(true);
        setResizable(false);
        setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
        messageLabel = new JLabel(message);
        messageLabel.setFont(MESSAGE_FONT);
        messageLabel.setForeground(MESSAGE_COLOR);
        JPanel contentPane = new JPanel();
        contentPane.setBackground(BACKGROUND_COLOR);
        contentPane.add(messageLabel);
        setContentPane(contentPane);
        pack();
        Dimension screenSize = GraphicsEnvironment.getLocalGraphicsEnvironment().getDefaultScreenDevice().getDefaultConfiguration().getBounds().getSize();
        Point location = new Point(screenSize.width - POPUP_WIDTH - 10, screenSize.height - POPUP_HEIGHT - 10);
        setLocation(location);
        setVisible(true);
        TIMER.start();
        new Thread(new Runnable() {
            @Override
            public void run() {
                Rectangle screenRect = new Rectangle(location, new Dimension(POPUP_WIDTH, POPUP_HEIGHT));
                int messageWidth = messageLabel.getPreferredSize().width;
                int x = screenRect.x + screenRect.width;
                while (x > screenRect.x - messageWidth) {
                    x -= SCROLL_SPEED;
                    messageLabel.setLocation(x, 0);
                    try {
                        Thread.sleep(20);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            }
        }).start();
    }

    public static void main(String[] args) {
        new MessagePopup("这是一条测试消息！");
    }
}

这个实现使用了 Java Swing 库中的 JFrame、JLabel 和 JPanel 组件，以及 Timer 和 Thread 类来实现弹窗的自动关闭和文字滚动效果。弹窗的大小和位置可以根据屏幕大小自适应，文字滚动速度和字体颜色、背景颜色等都可以自定义。