JComboBox有一个

SelectedItem属性，所以使用getSelectedItem()就可以得到当前选中值.

1 package ltb20180106;  2   3 import javax.swing.*;  4 import java.awt.event.*;  5 import java.awt.*;  6   7   8 public class UserLoginApp {  9      10     private JFrame jf; 11     private JLabel name; 12     private JLabel user; 13     private JLabel password; 14     private JButton confirm; 15     private JButton cancel;  16     private JButton quit; 17      18     private JPanel p1; 19     private JPanel p2; 20     private JpanelAction p3; 21     private JPanel p4; 22      23     private JComboBox 
     
       juser; 24     private JTextField jname; 25     private JPasswordField jpassword; 26      27     private String[] s= {"学生用户","教师用户"}; 28  29      30      31     private String ss; 32     private char[] c; 33     private String bname; 34     private String item; 35      36  37     public UserLoginApp() { 38          39         try { 40              41             jf=new JFrame("用户登录"); 42             jf.setSize(250, 160); 43             jf.setLayout(new BorderLayout()); 44              45              46             name=new JLabel("名字:"); 47             password=new JLabel("密码:"); 48             user=new JLabel("用户类型"); 49              50             juser=new JComboBox
      
       (s); 51             jname=new JTextField(); 52             jpassword=new JPasswordField();  53              54             confirm=new JButton("确定"); 55             cancel=new JButton("取消"); 56             quit=new JButton("退出"); 57              58             p1=new JPanel(); 59             p1.setLayout(new BoxLayout(p1,BoxLayout.Y_AXIS));//允许垂直或水平布置多个组件的布局管理器 60             p1.add(user); 61             p1.add(name); 62             p1.add(password); 63             p1.setSize(100,100); 64              65             p2=new JPanel(); 66             p2.setLayout(new BoxLayout(p2,BoxLayout.Y_AXIS)); 67             p2.add(juser); 68             p2.add(jname); 69             p2.add(jpassword); 70             p2.setSize(150,100); 71          72              73              74             p3=new JpanelAction();                75             p3.setLayout(new FlowLayout()); 76             p3.add(confirm); 77             p3.add(cancel); 78             p3.add(quit); 79             confirm.addActionListener(p3); 80             cancel.addActionListener(p3); 81             quit.addActionListener(p3); 82              83              84             p4=new JPanel(); 85             p4.setLayout(new FlowLayout()); 86             p4.add(p1); 87             p4.add(p2); 88              89             jf.add(p4,BorderLayout.NORTH); 90             jf.add(p3,BorderLayout.CENTER); 91              92             jf.setVisible(true); 93             jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 94             jf.setLocationRelativeTo(null); 95              96              97         }catch(Exception e) { 98              99             System.out.println(e.getMessage());100             101         }102         103         104     }105     106     107     108     109     @SuppressWarnings("serial")110     class JpanelAction extends JPanel  implements ActionListener   {111 112         113         public void actionPerformed(ActionEvent e) 114         {115             116              bname=e.getActionCommand();//关键的地方117              118             if(bname.equals("确定")) {119                 120                 ss=jname.getText(); 121                 c=jpassword.getPassword();122                 item=(String)juser.getSelectedItem();// JComboBox 当前所选项123                 124                 125                 if(ss.equals("")) {126                     127                     name.setText("用户名不能为空");128                     129                 } else if(c.length==0) {  130                     131                     password.setText("密码不能为空");132                     133                 }else if(item.equals("学生用户")) {134                     135                     if(ss.equals("s")&&new String(c).equals("s")) {
   //密码字符转化字符串处理136                         137                         name.setText("登录成功");138                         password.setText("登录成功");139                     }          140                     System.out.println("学生");141                     142                 }else if(item.equals("教师用户")) {143                     144                     if(ss.equals("t")&&new String(c).equals("t")) {
   //密码字符转化字符串处理145                         146                         name.setText("登录成功");147                         password.setText("登录成功");148                         149                     }150                     151                     System.out.println("教师");152                 }153                                                                                               154                 155             }else if (bname.equals("取消")) {156                 157                 jname.setText("");158                 jpassword.setText("");159                 160             }else if(bname.equals("退出")){161             162                 jf.dispose();//释放由此 Window、其子组件及其拥有的所有子组件所使用的所有本机屏幕资源。163             }164         }165         166         167     }168 169     public static void main(String[] args) {170         171           new UserLoginApp();172     }173 174 }