系统入口类中这样：LoginFrame lf=new LoginFrame();lf.setVisible(true);LoginFrame 中，按钮“OK”的监听事件这样：……//连接数据库，并验证用户名和密码if(success)//验证成功MainFrame mf=new MainFrame();mf.setVisible(true);dispose(); //销毁LoginFrameelse提示错误信息2import javax.swing.*;import java.awt.*;import java.awt.event.*;//下面代码创建JFrame框架窗体class FrameTest extends JFrame{public FrameTest(){super("客户登录");setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);setVisible(true);setSize(406,195);}}//下面代码创建JPanel面板，并将面板添加到框架窗体class PanelTest extends FrameTest{JPanel panelObj;public PanelTest(){panelObj=new JPanel();getContentPane().add(panelObj);}}//下面代码创建javax.swing控件，并将控件添加到面板class ComponentTest extends PanelTest //构造组件类{JLabel labelName; //姓名JLabel labelMima; //密码JTextField textName; //文本框JTextField textMima; //文本框JButton buttonObj1; //确定按钮JButton buttonObj2; //重置按钮public ComponentTest(){labelName =new JLabel("姓名 ");labelMima =new JLabel("密码 ");textName =new JTextField(25);textMima =new JTextField(15);buttonObj1 =new JButton("确定");buttonObj2 =new JButton("重置");buttonObj1.setEnabled(true); //使能buttonObj2.setEnabled(false); //不使能panelObj.add(labelName);panelObj.add(textName);panelObj.add(labelMima);panelObj.add(textMima);panelObj.add(buttonObj1);panelObj.add(buttonObj2);}}//下面代码创建GridBagLayout布局管理器，并将布局应用到面板class LayoutManagerTest extends ComponentTest //构造布局类{GridBagLayout gbLayoutObj;GridBagConstraints gbcObj;public LayoutManagerTest(){gbLayoutObj=new GridBagLayout();gbcObj=new GridBagConstraints();panelObj.setLayout(gbLayoutObj);gbcObj.anchor=GridBagConstraints.EAST;gbcObj.gridx=1;gbcObj.gridy=1;gbLayoutObj.setConstraints(labelName,gbcObj);gbcObj.gridy=2;gbLayoutObj.setConstraints(labelMima,gbcObj);gbcObj.gridy=3;gbLayoutObj.setConstraints(buttonObj1,gbcObj);gbcObj.anchor=GridBagConstraints.WEST;gbcObj.gridx=2;gbcObj.gridy=1;gbLayoutObj.setConstraints(textName,gbcObj);gbcObj.gridy=2;gbLayoutObj.setConstraints(textMima,gbcObj);gbcObj.gridy=3;gbLayoutObj.setConstraints(buttonObj2,gbcObj);}}class EventTest extends LayoutManagerTest{ButtonEvent bEObj;public EventTest(){bEObj=new ButtonEvent(); //创建事件类对象buttonObj1.addActionListener(bEObj); //注册监听器buttonObj2.addActionListener(bEObj); //注册监听器}class ButtonEvent implements ActionListener{public void actionPerformed(ActionEvent e){Object obj=e.getSource();Object[] options={" 确定 "," 取消 "};if(obj==buttonObj1){String strObj1=textName.getText();String strObj2=textMima.getText();String str1=new String("警告！姓名不能为空.");String str2=new String("警告！密码不能为空.");//if(strObj1.length()==0||strObj2.length()==0)// {if(strObj1.length()==0){ //String str1=new String("警告！姓名不能为空.");JOptionPane.showOptionDialog(null,str1,"警告窗口！",JOptionPane.DEFAULT_OPTION,JOptionPane.WARNING_MESSAGE,null,options,o ptions[0]);return;}else{if(strObj2.length()==0){ // String str2=new String("警告！密码不能为空.");JOptionPane.showOptionDialog(null,str2,"警告窗口！",JOptionPane.DEFAULT_OPTION,JOptionPane.WARNING_MESSAGE,null,options,o ptions[0]);return;}// }// }else{String str3=new String("文本框内容是:\n姓名："+strObj1+"\n密码"+strObj2);JOptionPane.showOptionDialog(null,str3,"确定窗口！", JOptionPane.DEFAULT_OPTION,RMATION_MESSAGE,null,optio ns,options[0]);buttonObj1.setEnabled(false);buttonObj2.setEnabled(true);}}}if(obj==buttonObj2){buttonObj2.setEnabled(false);buttonObj1.setEnabled(true);textName.setText("");textMima.setText("");String str1=new String("你单击了\" 重置(E) \"，清空文本框。

");JOptionPane.showOptionDialog(null,str1,"信息窗口！", JOptionPane.DEFAULT_OPTION,RMATION_MESSAGE,null,optio ns,options[0]);}}}}//下面代码是包含main()函数的公共类public class yonghudenglu extends EventTest{public static void main(String[] args){new yonghudenglu();}}3import java.awt.*;import javax.swing.*;public class guanli_chaozuo extends JFrame{ public JLabel jusername;public JLabel jpassword,jpassword_sure; public JTextField username;public JPasswordField password,password_sure; public JButton jb1,jb2;public void make_GUI(){jusername=new JLabel("用户名* ");jpassword=new JLabel("新密码* ");jpassword_sure=new JLabel("新密码确认*");jb1=new JButton("确定");jb2=new JButton("取消");username=new JTextField(10);password=new JPasswordField(10);password_sure=new JPasswordField(10);Container cp=getContentPane();JPanel jp=new JPanel();JPanel jp2 =new JPanel();jp.setLayout(new GridLayout(4,8,20,10));jp.add(jusername);jp.add(username);jp.add(jpassword);jp.add(password);jp.add(jpassword_sure);jp.add(password_sure); jp2.add(jb1);jp2.add(jb2);cp.add(jp,BorderLayout.CENTER);cp.add(jp2,BorderLayout.SOUTH);setSize(300,200);setVisible(true);}public guanli_chaozuo(String s){super(s);make_GUI();}public void exit(){this.dispose();}4import javax.swing.*;import java.awt.*;public class FlowLayoutDemo extends JFrame{ public FlowLayoutDemo(){setLayout(new BorderLayout(5,5));setFont(new Font("Helvetica",Font.PLAIN,14)); JLabel jlab1,jlab2,jlab3;jlab1=new JLabel(" 欢迎使用考试系统");jlab2=new JLabel("用户名：");jlab3=new JLabel("密码：");jlab1.setFont(new Font("隶书",Font.BOLD,24)); JButton B1=new JButton();JButton B2=new JButton();JButton B3=new JButton();JTextField username=new JTextField(15); JPasswordField password=new JPasswordField (15); B1=new JButton("登陆");B2=new JButton("注册");B3=new JButton("取消");JPanel p1=new JPanel();JPanel p2=new JPanel();JPanel p3=new JPanel();p1.add(jlab2);p1.add(jlab3);p2.add(username);p2.add(password);p3.add(B1);p3.add(B2);p3.add(B3);password.setEchoChar('*');JTextField flab2;JTextField flab3;add("North", jlab1);add("West",p1);add("Center",p2);add("South",p3);}public static void main(String[] args) { FlowLayoutDemo window=new FlowLayoutDemo(); window.setTitle("用户登陆");window.setSize(300,200);window.setLocationRelativeTo(null); window.setResizable(false);window.setVisible(true);window.setDefaultCloseOperation(EXIT_ON_CLOSE); }}。