import java.awt.*;import javax.swing.*;import java.awt.event.*;public class Login extends JFrame {   JTextField usernameTextField;   JPasswordField pwdPasswordField;   JButton submint,close;   JLabel usenameLabel,pwdLabel;   public Login(){      usenameLabel=new JLabel("用户名:",JLabel.RIGHT);      pwdLabel=new JLabel("密码:",JLabel.RIGHT);      usernameTextField=new JTextField(10);      pwdPasswordField=new JPasswordField(10);      submint=new JButton("登录");      close=new JButton("关闭");      setLayout(new GridLayout(3,2));      add(usenameLabel);      add(usernameTextField);      add(pwdLabel);      add(pwdPasswordField);      add(submint);      add(close);           setDefaultCloseOperation(EXIT_ON_CLOSE);      setSize(260,150);      setLocationRelativeTo(null);      setVisible(true);    }    public static void main(String[] args){        Login login=new Login();    }          }