package Login;import java.awt.*;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;import java.awt.event.MouseAdapter;import java.awt.event.MouseEvent;import java.awt.event.MouseAdapter;import java.awt.event.MouseEvent;import java.awt.event.MouseListener;import java.awt.event.WindowAdapter;import java.awt.event.WindowEvent;import javax.swing.*;import java.math.*;public class NewGUI extends JFrame implements ActionListener{    private JLabel name,pass,yzm,code,jpg;    private JTextField tf1,tf3,tf4;    private JPasswordField tf2,tf5;    private Button login,register1,register2,jp1;    private JPanel back,jp2;    private JFrame j1,j2;    private Icon icon;    static String str,user,pwd;            public static void main(String[] args) {    NewGUI ng = new NewGUI();    ng.ShowFrame();    }        public void ShowFrame() {        j1 = new JFrame();        j1.setTitle("登录窗口");        //j.setLayout(new FlowLayout());        j1.setLayout(null); //自定义布局                //设置账号及其输入框        name = new JLabel("账号:");        Font font = new Font("楷体", Font.PLAIN, 15);        tf1 = new JTextField("用户名/邮箱",20);        tf1.setFont(font);        tf1.addMouseListener(new MouseAdapter()                {                    public void mouseClicked(MouseEvent e)                    {                        if (e.getButton() == MouseEvent.BUTTON1)                            tf1.setText("");                    }                });        name.setBounds(70, 13, 60, 40);        tf1.setBounds(110, 20, 210, 25);        tf1.addActionListener(this);                //设置密码及其输入框        pass = new JLabel("密码:");        tf2 = new JPasswordField(20);        pass.setBounds(70, 53, 60, 40);        tf2.setBounds(110, 60, 210, 25);                //设置验证码输入框并添加到面板三        yzm = new JLabel("验证码:");        tf3 = new JTextField(5);        yzm.setBounds(58, 93, 60, 40);        tf3.setBounds(110, 100, 100, 25);                //设置面板来存验证码            paint();                //设置登陆按钮        login = new Button("登陆");        login.setBackground(Color.orange);        login.setBounds(80, 150, 240, 40);        login.addActionListener(this);                //设置注册按钮        register1 = new Button("注册");        register1.setBackground(Color.orange);        register1.setBounds(80, 205, 240, 40);        register1.addActionListener(this);        //        //设置背景面板//        jp2 = new JPanel();//        jp2.setSize(400, 300);//        jp2.setBackground(Color.white);                    //将组件放到窗口上        j1.add(name);        j1.add(tf1);        j1.add(pass);        j1.add(tf2);        j1.add(yzm);        j1.add(tf3);        j1.add(login);        j1.add(register1);        j1.add(jpg);        j1.add(jp1);      //  j1.add(jp2);        j1.setVisible(true);        j1.setSize(400, 300);        j1.setLocationRelativeTo(null);        j1.setResizable(false);        j1.setDefaultCloseOperation(3);    }    public void Register() {        JFrame j2 = new JFrame();        j2.setTitle("注册界面");        //j.setLayout(new FlowLayout());        j2.setLayout(null); //自定义布局                //设置账号及其输入框        name = new JLabel("账号:");        Font font = new Font("楷体", Font.PLAIN, 15);        tf4 = new JTextField("用户名/邮箱",20);        tf4.setFont(font);        tf4.addMouseListener(new MouseAdapter()                {                    public void mouseClicked(MouseEvent e)                    {                        if (e.getButton() == MouseEvent.BUTTON1)                            tf4.setText("");                    }                });        name.setBounds(100, 13, 60, 40);        tf4.setBounds(140, 20, 120, 25);        tf4.addActionListener(this);                //设置密码及其输入框        pass = new JLabel("密码:");        tf5 = new JPasswordField(20);        pass.setBounds(100, 53, 60, 40);        tf5.setBounds(140, 60, 120, 25);                //设置注册按钮        register2 = new Button("立即注册");        register2.setBackground(Color.orange);        register2.setBounds(75, 125, 240, 40);        register2.addActionListener(this);        register2.addMouseListener(new MouseAdapter()        {            public void mouseClicked(MouseEvent e)            {                if (e.getButton() == MouseEvent.BUTTON1)                    {                    if(!tf4.getText().equals("")&&!tf5.getText().equals("")) {                        user=tf4.getText();                        pwd=tf5.getText();                        JOptionPane.showMessageDialog(null, "注册成功！");                        j2.setVisible(false);}                        else {                            tf4.setText("");                            tf5.setText("");                            JOptionPane.showMessageDialog(null, "请输入完整信息！");                        }                    }            }        });        //        //设置背景面板//        jp2 = new JPanel();//        jp2.setSize(400, 250);//        jp2.setBackground(Color.white);                    //将组件放到窗口上        j2.add(name);        j2.add(tf4);        j2.add(pass);        j2.add(tf5);        j2.add(register2);//        j2.add(jp2);        j2.setVisible(true);        j2.setSize(400, 250);        j2.setLocationRelativeTo(null);        j2.setResizable(false);    }    public  String BulidChar() {        String str1="";        for(int i=0;i<4;i++) {        int x=0;        int a = (int)(Math.random()*3);        if(a==0) {                x = (int)(Math.random()*10+48);        }        if(a==1) {                x = (int)(Math.random()*26+65);        }        if(a==2) {                x = (int)(Math.random()*26+97);        }            str1=str1+(char)x;            }        return str1;    }    public void paint() {        icon = new ImageIcon("src/1.png");        jpg = new JLabel();        jpg.setIcon(icon);        jpg.setBounds(215, 102, 20, 20);        str=BulidChar();        jp1 = new Button(str);        jp1.setBounds(240, 100, 80, 25);        jp1.setBackground(Color.gray);        jp1.addMouseListener(new MouseAdapter() {            @Override            public void mouseClicked(MouseEvent e) {                if(e.getButton()== MouseEvent.BUTTON1)                {                    jp1.setVisible(false);                    paint();                    j1.add(jp1);                }            }        });    }    public void actionPerformed(ActionEvent e) {                if(e.getActionCommand()=="登陆") {            if(tf1.getText().equals("用户名/邮箱")||tf1.getText().equals(""))            {                JOptionPane.showMessageDialog(null,"请输入用户名！");                tf1.setText("");                tf2.setText("");                tf3.setText("");                jp1.setVisible(false);                paint();                j1.add(jp1);            }            else if(tf2.getText().equals(""))            {                JOptionPane.showMessageDialog(null,"请输入密码！");                tf1.setText("");                tf2.setText("");                tf3.setText("");                jp1.setVisible(false);                paint();                j1.add(jp1);            }            else if(tf3.getText().equals(""))            {                JOptionPane.showMessageDialog(null,"请输入验证码！");                tf1.setText("");                tf2.setText("");                tf3.setText("");                jp1.setVisible(false);                paint();                j1.add(jp1);            }            else if((!str.equals(tf3.getText())))            {                JOptionPane.showMessageDialog(null, "验证码错误！"+str);                tf1.setText("");                tf2.setText("");                tf3.setText("");                jp1.setVisible(false);                paint();                j1.add(jp1);            }            else if(!tf1.getText().equals(user))            {                JOptionPane.showMessageDialog(null,"用户名不存在！");                tf1.setText("");                tf2.setText("");                tf3.setText("");                jp1.setVisible(false);                paint();                j1.add(jp1);            }//            else if(((tf1.getText()).equals(user))&&(tf2.getText().equals("")))//            {//                JOptionPane.showMessageDialog(null,"请输入密码！");//                tf1.setText("");//                tf2.setText("");//                tf3.setText("");//                j1.setVisible(false);//                ShowFrame();//                paint();//            }            else if(((tf1.getText()).equals(user))&&(!(tf2.getText()).equals(pwd)))            {                JOptionPane.showMessageDialog(null,"密码不正确！");                tf1.setText("");                tf2.setText("");                tf3.setText("");                jp1.setVisible(false);                paint();                j1.add(jp1);            }            else if(((tf1.getText()).equals(user))&&((tf2.getText()).equals(pwd))&&(tf3.getText().equals("")))            {                JOptionPane.showMessageDialog(null, "请输入验证码！");                tf1.setText("");                tf2.setText("");                tf3.setText("");                jp1.setVisible(false);                paint();                j1.add(jp1);            }            else if(((tf1.getText()).equals(user))&&(!(tf2.getText()).equals(pwd))&&(!str.equals(tf3.getText())))            {                JOptionPane.showMessageDialog(null, "验证码错误！"+str);                tf1.setText("");                tf2.setText("");                tf3.setText("");                jp1.setVisible(false);                paint();                j1.add(jp1);            }            else{                JOptionPane.showMessageDialog(null, "登陆成功！");            }        }        else if(e.getActionCommand()=="注册") {            Register();        }    }}

功能：

（1）未输入用户名便登陆

 

 

（2）未输入密码便登陆

 

 

（3）未输入验证码便登陆

 

 

（4）输入账号密码，验证码错误

 

 

（5）账号密码输入，验证码输入正确，但用户名不存在

 

 

（6）注册

 

 

（7）注册成功

 

 

（8）账号存在，验证码正确，密码错误

 

 

（9）账号密码验证码正确

 

 

（10）单击验证码，更换验证码

 

变为