如何在失去焦点的情况下保留分配给JDialog的光标？

import javax.swing.*;
import java.awt.*;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.event.WindowFocusListener;

public class Main {
    public static void main(String[] args) {
        // 创建JDialog
        JDialog dialog = new JDialog();
        dialog.setSize(300, 200);

        // 创建文本框组件
        JTextArea textArea = new JTextArea();
        dialog.add(textArea);

        // 添加WindowFocusListener监听器
        dialog.addWindowFocusListener(new WindowFocusListener() {
            int caretPosition;

            @Override
            public void windowGainedFocus(WindowEvent e) {
                // 当JDialog获得焦点时，将焦点设置到文本框组件上
                textArea.requestFocus();
            }

            @Override
            public void windowLostFocus(WindowEvent e) {
                // 当JDialog失去焦点时，保存当前光标位置
                caretPosition = textArea.getCaretPosition();
            }
        });

        // 关闭JDialog时退出程序
        dialog.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
        dialog.addWindowListener(new WindowAdapter() {
            public void windowClosed(WindowEvent e) {
                System.exit(0);
            }
        });

        // 显示JDialog
        dialog.setVisible(true);
    }
}