如何清除JTextField并使其准备好立即输入，而无需单击或其他操作？

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class ClearTextFieldExample {
    public static void main(String[] args) {
        JFrame frame = new JFrame("Clear JTextField Example");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        JPanel panel = new JPanel();

        JTextField textField = new JTextField(20);
        panel.add(textField);

        JButton clearButton = new JButton("Clear");
        panel.add(clearButton);

        clearButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                textField.setText("");
                textField.requestFocusInWindow();
            }
        });

        frame.add(panel);
        frame.pack();
        frame.setVisible(true);
    }
}