图书馆管理系统登陆界面

1 程序代码 package window import data BaseDao import java awt AWTEvent import java awt Container import java awt Font import java awt GridLayout import java awt event ActionEvent import java awt event ActionListener import java awt event KeyAdapter import java awt event KeyEvent import java sql ResultSet import javax swing import javax swing plaf FontUIResource import util GlobalVar 类 Login 用于显示登录界面 要求系统用户输入正确的用户名和密码 author raymond public class Login extends JFrame private JLabel lb user private JTextField tf user private JLabel lb pass private JPasswordField pf pass private JButton btn ok private JButton btn cancel private int num 0 用来记录登陆不成功的次数 public Login UIUtil setUIFont new FontUIResource 宋体 Font BOLD 15 initComponents 初始化组件 private void initComponents lb user new JLabel tf user new JTextField 用户名输入文本框 lb pass new JLabel pf pass new JPasswordField 密码输入文本框 btn ok new JButton 确认按钮 btn cancel new JButton 取消按钮 setTitle 用户登录界面 setResizable false setDefaultCloseOperation JFrame EXIT ON CLOSE Container contentPane getContentPane contentPane setLayout new GridLayout 3 2 lb user setText 用户名 lb user setHorizontalAlignment SwingConstants RIGHT tf user addKeyListener new KeyEnter contentPane add lb user contentPane add tf user lb pass setText 密码 lb pass setHorizontalAlignment SwingConstants RIGHT pf pass addKeyListener new KeyEnter contentPane add lb pass contentPane add pf pass btn ok setText 确定 btn ok addActionListener new ActionListener Override public void actionPerformed ActionEvent e btn okActionPerformed e contentPane add btn ok btn cancel setText 取消 btn cancel addActionListener new ActionListener Override public void actionPerformed ActionEvent e btn cancelActionPerformed e contentPane add btn cancel setSize 225 150 setLocationRelativeTo getOwner 确定 按钮响应事件 private void btn okActionPerformed AWTEvent e String user tf user getText 获得用户名 String pass String valueOf pf pass getPassword 获得密码 String username int is admin 未输入用户名 if user equals JOptionPane showMessageDialog this 用户名不允许为空 return try 在数据库中查询 String sqlStr select from users where name user and pass pass ResultSet result BaseDao executeQuery sqlStr if result next username result getString name is admin result getInt is admin BaseDao close else JOptionPane showMessageDialog this 用户名或密码不正确 BaseDao close 当登录不成功次数超过 3 次 则自动退出 if num 3 num else JOptionPane showMessageDialog this 尝试次数过多 this dispose return GlobalVar login user username 记录当前用户 进入主界面 Main main new Main main setPurView byte is admin this dispose catch Exception ex System out println ex getMessage 取消 按钮响应事件 private void btn cancelActionPerformed ActionEvent e this dispose 接受键盘响应事件 private class KeyEnter extends KeyAdapter Override public void keyPressed KeyEvent e int keycode e getKeyCode if keycode KeyEvent VK ENTER btn okActionPerformed e public static void main String args new Login setVisible true 2 界面截图 图 1 登录界面 图 2 当输入的用户名为空时 弹出的消息框 图 3 当输入的用户名或密码不正确时 弹出的消息框