java编写的桌面程序怎么清除密码框中的内容

java编写的具有注册功能的桌面程序，当两次密码输入不一致时，清除密码框的内容，但是不清除已经输入的用户名等其他信息，请问各位大佬这个功能该如何实现？

import java.awt.BorderLayout;
import java.awt.EventQueue;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;
import javax.swing.JPasswordField;
import javax.swing.JTextField;
import javax.swing.JLabel;
import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;

public class PasswordText extends JFrame {

	private JPanel contentPane;
	private JPasswordField passwordField;
	private JTextField textField;

	/**
	 * Launch the application.
	 */
	public static void main(String[] args) {
		EventQueue.invokeLater(new Runnable() {
			public void run() {
				try {
					PasswordText frame = new PasswordText();
					frame.setVisible(true);
				} catch (Exception e) {
					e.printStackTrace();
				}
			}
		});
	}

	/**
	 * Create the frame.
	 */
	public PasswordText() {
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		setBounds(100, 100, 450, 300);
		contentPane = new JPanel();
		contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
		setContentPane(contentPane);
		contentPane.setLayout(null);

		passwordField = new JPasswordField();
		passwordField.setBounds(121, 118, 152, 21);
		contentPane.add(passwordField);

		textField = new JTextField();
		textField.setBounds(119, 87, 154, 21);
		contentPane.add(textField);
		textField.setColumns(10);

		JLabel lblNewLabel = new JLabel("Username");
		lblNewLabel.setBounds(20, 90, 54, 15);
		contentPane.add(lblNewLabel);

		JLabel lblNewLabel_1 = new JLabel("Password");
		lblNewLabel_1.setBounds(20, 121, 54, 15);
		contentPane.add(lblNewLabel_1);

		JButton btnNewButton = new JButton("Login");
		btnNewButton.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				if (!passwordField.getText().equals("password")) {
					passwordField.setText("");
				}
			}
		});
		btnNewButton.setBounds(180, 174, 93, 23);
		contentPane.add(btnNewButton);
	}
}

不知道 我知道qt 是调用ui指向需要清理的.调用clear   c艹的也是