Java GUI事件处理及添加对话框实现方式

jButton1.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                System.out.println("点击登录");
            }
        });

jButton2.addMouseListener(new MouseListener() {
            @Override
            public void mouseClicked(MouseEvent e) {
                System.out.println("鼠标点击");
            }

            @Override
            public void mousePressed(MouseEvent e) {
                System.out.println("鼠标按下，但没有松开");
            }

            @Override
            public void mouseReleased(MouseEvent e) {
                System.out.println("鼠标松开");
            }

            @Override
            public void mouseEntered(MouseEvent e) {
                System.out.println("鼠标悬停");
            }

            @Override
            public void mouseExited(MouseEvent e) {
                System.out.println("鼠标移走");
            }
        });

jTextField.addKeyListener(new KeyListener() {
            @Override
            public void keyTyped(KeyEvent e) {
//                System.out.println("键盘输入完成");
            }

            @Override
            public void keyPressed(KeyEvent e) {
//                System.out.println("键盘按下");
            }

            @Override
            public void keyReleased(KeyEvent e) {
//                "释放键盘"
                System.out.println(jTextField.getText());
            }
        });

this.addWindowListener(new WindowAdapter() {//窗口适配器WindowAdapter，也可使用new WindowListener()
            @Override
            public void windowClosing(WindowEvent e) {
                int res = JOptionPane.showConfirmDialog(null,"确定退出聊天室？","操作提示",JOptionPane.OK_CANCEL_OPTION);//弹出一个对话框
                if (res == 0){//确认退出
                    dispose()；
                }
            }
        });

JOptionPane.showMessageDialog(null, "发送内容不能为空");

JOptionPane.showConfirmDialog(null,"确定退出聊天室？","操作提示",JOptionPane.OK_CANCEL_OPTION);