How to implement login window in java

Login window main class

package ccnu.paint;

import java.awt.Color;
import java.awt.Font;
import java.awt.GridLayout;
import java.awt.Point;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.Enumeration;
import java.util.Properties;

import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JPasswordField;
import javax.swing.JTextField;

import ccnu.util.Answer;
import ccnu.util.Verification;

public class Login extends JFrame
{
    private static final long serialVersionUID = 1L;

    private Properties pro = new Properties();

    private boolean ver_code = false; // 默认输入验证码错误

    private Answer answer = null;

    private JPanel p1 = new JPanel(); // 添加到JPanel中的组件默认为流式布局
    private JLabel luser = new JLabel("username: ");
    private JTextField username = new JTextField(20);

    private JPanel p2 = new JPanel();
    private JLabel lpwd = new JLabel("password: ");
    private JPasswordField pwd = new JPasswordField(20);

    private JPanel p4 = new JPanel();
    private JLabel lVer = new JLabel("verification: ");
    private JTextField ver = new JTextField(10);
    private JLabel img = new JLabel();
    private JLabel result = new JLabel();

    private JPanel p3 = new JPanel();
    private JButton ok = new JButton("ok");
    private JButton cancel = new JButton("cancel");
    private JButton signUp = new JButton("Sign up"); // 用于账户注册

    // 设置组件的监听
    public void initListener()
    {
        username.addActionListener(new ActionListener()
        {
            @Override
            public void actionPerformed(ActionEvent e)
            {// JTextField的action是回车键
                String name = username.getText();
                // Login.this.setTitle(name);
                // System.out.println(name.hashCode() + "***" +"".hashCode());
                if (name.equals(""))
                {
                    JOptionPane.showMessageDialog(Login.this, "Please input a userName!");
                } else
                {
                    pwd.grabFocus();
                }
            }
        });

        pwd.addActionListener(new ActionListener(){
            @Override
            public void actionPerformed(ActionEvent e)
            {
                String password = new String(pwd.getPassword());
                if(password.equalsIgnoreCase(""))
                {
                    JOptionPane.showMessageDialog(Login.this, "please input a password!");
                }else{
                    ver.grabFocus();
                }
            }

        });

        ok.addActionListener(new ActionListener(){

            @Override
            public void actionPerformed(ActionEvent e)
            {
                // 重新加载最新的账户文件
                try
                {
                    pro.load(new FileInputStream(new File("src/res/accouts.properties")));
                } catch (IOException e1)
                {
                    e1.printStackTrace();
                }
                check();
            }

        });

        // 判断验证码是否正确
        ver.addActionListener(new ActionListener(){
            @Override
            public void actionPerformed(ActionEvent e)
            {
                String verCode = ver.getText();
                if(verCode.equals(""))
                {
                    JOptionPane.showMessageDialog(Login.this, "Please input a verification!");
                }else{
                    if(verCode.equals(answer.getResult()))
                    {
                        result.setIcon(new ImageIcon(Login.this.getClass().getResource("/res/right.jpg"))); // 显示提示的图片信息(如√图片)
                        ver_code = true;
                        // 检查之前，重新加载最新的账户文件
                        try
                        {
                            pro.load(new FileInputStream(new File("src/res/accouts.properties"))); // 将账户文件加载进来
                        } catch (IOException e1)
                        {
                            e1.printStackTrace();
                        }
                        check();
                    }else{
                        result.setIcon(new ImageIcon(Login.this.getClass().getResource("/res/error.jpg"))); // 显示提示的图片信息(如×图片) 
                        ver_code = false;
                    }
                }
            }
        });

        // 点击图片会更改验证码
        img.addMouseListener(new MouseAdapter(){

            @Override
            public void mouseClicked(MouseEvent e)
            {
                answer = Verification.verification();
                img.setIcon(new ImageIcon(answer.getBufferedImage())); // 设置验证码图案
            }
        });

        cancel.addActionListener(new ActionListener()
        {
            @Override
            public void actionPerformed(ActionEvent e)
            {
                int option = JOptionPane.showConfirmDialog(Login.this, "Are you sure to exit?");
//              System.out.println("option = " + option);
                if (option == 0)
                {// Yes
                    Login.this.dispose();
                }
            }
        });

        signUp.addActionListener(new ActionListener(){

            @Override
            public void actionPerformed(ActionEvent e)
            {
                new SignUp();
            }
        });
    }

    // 初始化登录窗口及其组件的设置监听
    public Login()
    {
        super("Login");

        // 加载账户文件
        try
        {
            pro.load(new FileInputStream(new File("src/res/accouts.properties"))); // 从指定位置将账户文件加载进来
        } catch (IOException e)
        {
            e.printStackTrace();
        }

        initListener();
        answer = Verification.verification(); // 生成验证码
        img.setIcon(new ImageIcon(answer.getBufferedImage())); // 设置初始验证码

        this.setLocation(new Point(200, 200));
        this.setSize(500, 300);
        this.setLayout(new GridLayout(4, 1, 0, 20)); // 垂直间隙为20px
        p1.add(luser);
        p1.add(username);
        p2.add(lpwd);
        p2.add(pwd);
        p4.add(this.lVer);
        p4.add(this.ver);
        p4.add(this.img);
        result.setForeground(Color.red);
        result.setFont(new Font("楷体", Font.BOLD, 20));
        p4.add(result);
        p3.add(ok);
        p3.add(cancel);
        p3.add(signUp);
        this.add(p1);
        this.add(p2);
            this.add(p4);
        this.add(p3);

//      this.setBackground(Color.blue); // JFrame的上层还有一个ContentPane
        this.getContentPane().setBackground(Color.gray);
        this.setResizable(false);
        this.setVisible(true);
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); // 等价于Frame中的windowClosing事件
    }

    // 检查用户名或密码
    public void check()
    {

        String verCode = ver.getText();
        if(verCode.equals(""))
        {
            JOptionPane.showMessageDialog(Login.this, "Please input a verification!");
            return;
        }else{
            if(verCode.equals(answer.getResult()))
            {
                result.setIcon(new ImageIcon(Login.this.getClass().getResource("/res/right.jpg")));
                ver_code = true;
            }else{
                result.setIcon(new ImageIcon(Login.this.getClass().getResource("/res/error.jpg")));
                ver_code = false;
            }
        }

        if(ver_code == false)
        {
            JOptionPane.showMessageDialog(this, "verification is error!");
            return;
        }
        String name = username.getText();
        String password = new String(pwd.getPassword()); // return char[]
//      if (name.equalsIgnoreCase("admin") && password.equals("123456"))
        if (isPass(name, password))
        {
//          new PaintApp(name);
            JOptionPane.showMessageDialog(this, "-^_^-   OK..."); // 此处可以加上其他的登陆成功后进一步处理的窗口
            this.dispose();
        } else
        {
            JOptionPane.showMessageDialog(this, "userName or password is incorrect!");
            username.setText("");
            pwd.setText("");
            ver.setText("");
            answer = Verification.verification();
            img.setIcon(new ImageIcon(answer.getBufferedImage()));
            result.setIcon(null);
        }
    }

    // 验证用户输入的账户名和密码是否正确(通过与加载进来的账户 pro 比对)
    public boolean isPass(String name, String password)
    {
        Enumeration en = pro.propertyNames();
        while(en.hasMoreElements())
        {
            String curName = (String)en.nextElement();
//          System.out.println(curName + "---" + pro.getProperty(curName));
            if(curName.equalsIgnoreCase(name))
            {
                if(password.equalsIgnoreCase(pro.getProperty(curName)))
                {
                    return true;
                }
            }
        }
        return false;
    }

    public static void main(String[] args)
    {
        new Login();
    }
}

Account registration class

package ccnu.paint;

import java.awt.GridLayout;
import java.awt.Point;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Enumeration;
import java.util.Properties;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JPasswordField;
import javax.swing.JTextField;

public class SignUp extends JFrame
{
    private static final long serialVersionUID = 3054293481122038909L;

    private Properties pro = new Properties(); // 最好时静态的，因为账户是共享的

    private JPanel panel = new JPanel();
    private JLabel label = new JLabel("username: ");
    private JTextField field = new JTextField(15);

    private JPanel panel2 = new JPanel();
    private JLabel label2 = new JLabel("password: ");
    private JPasswordField field2 = new JPasswordField(15);

    private JPanel panel3 = new JPanel();
    private JLabel label3 = new JLabel("confirmation: ");
    private JPasswordField field3 = new JPasswordField(15);

    private JPanel panel4 = new JPanel();
    private JButton button = new JButton("OK");
    private JButton button2 = new JButton("Cancel");

    public void initListener()
    {
        field.addActionListener(new ActionListener()
        {

            @Override
            public void actionPerformed(ActionEvent e)
            {
                field2.grabFocus();
            }

        });

        field2.addActionListener(new ActionListener()
        {

            @Override
            public void actionPerformed(ActionEvent e)
            {
                field3.grabFocus();
            }
        });
        field3.addActionListener(new ActionListener()
        {

            @Override
            public void actionPerformed(ActionEvent e)
            {
                ok_actionPerformed(e);
            }

        });

        // OK
        button.addActionListener(new ActionListener()
        {

            @Override
            public void actionPerformed(ActionEvent e)
            {
                ok_actionPerformed(e);
            }
        });

        // Cancel
        button2.addActionListener(new ActionListener()
        {

            @Override
            public void actionPerformed(ActionEvent e)
            {
                cancel_actionPerformed(e);
            }
        });
    }

    public void ok_actionPerformed(ActionEvent e)
    {
        String userName = field.getText();
        String password = new String(field2.getPassword());
        String password2 = new String(field3.getPassword());
        if (userName.equals(""))
        {
            JOptionPane.showMessageDialog(SignUp.this, "username cannot be empty!");
        } else
        {
            if (password.equalsIgnoreCase(""))
            {
                JOptionPane.showMessageDialog(SignUp.this, "password cannot be empty!");
            } else
            {
                if (password2.equalsIgnoreCase(password))
                {
                    if (isExist(userName))
                    {
                        JOptionPane.showMessageDialog(SignUp.this, "username has been existed!");
                        field.setText("");
                        field2.setText("");
                        field3.setText("");
                    } else
                    {
                        pro.setProperty(userName, password);
                        JOptionPane.showMessageDialog(SignUp.this, "SignUp success!");
                        writeToPro(userName, password); // 将其写入到账户文件中
                        SignUp.this.dispose();
                    }
                } else
                {
                    JOptionPane.showMessageDialog(SignUp.this, "password is not consistent!");
                    field2.setText("");
                    field3.setText("");
                }
            }
        }
    }

    public void cancel_actionPerformed(ActionEvent e)
    {
        System.exit(0);
    }

    public SignUp()
    {
        super("Sign up");

        // 加载账户文件
        try
        {
            pro.load(new FileInputStream(new File("src/res/accouts.properties")));
        } catch (IOException e)
        {
            e.printStackTrace();
        }

        // 初始化窗口组件的监听
        initListener();

        this.setLocation(new Point(300, 230));
        this.setSize(280, 210);

        this.setLayout(new GridLayout(4, 1, 0, 20)); // 垂直间隙为20px
        panel.add(label);
        panel.add(field);
        panel2.add(label2);
        panel2.add(field2);
        panel3.add(label3);
        panel3.add(field3);
        panel4.add(button);
        panel4.add(button2);
        this.add(panel);
        this.add(panel2);
        this.add(panel3);
        this.add(panel4);

        this.setAlwaysOnTop(true);
        this.setResizable(false);
        this.setVisible(true);
    }

    // 如果注册始终可用,就要保存起来，否则不需要写入文件中，注册账户本次使用
    // 将账户名与其对应密码保存到指定的账户文件中
    public void writeToPro(String userName, String password)
    {
        pro.setProperty(userName, password);
        try
        {
            pro.store(new FileOutputStream(new File("src/res/accouts.properties")), "allAccouts");
        } catch (IOException e)
        {
            e.printStackTrace();
        }
    }


    // 判断此用户名是否已经存在
    public boolean isExist(String userName)
    {
        Enumeration enumer = pro.propertyNames();
        while (enumer.hasMoreElements())
        {
            String temp = (String) enumer.nextElement();
            if (temp.equals(userName))
            {
                return true;
            }
        }
        return false;
    }
}

Generate verification code class

package ccnu.util;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Point;
import java.awt.image.BufferedImage;
import java.util.Random;

// 用于生成验证码
public class Verification
{
    private static Answer answer = new Answer();
    private static BufferedImage bufferedImage = null;
    private static String result = null;
    private static String words = null;
    private static String words2 = null;

    // 生成验证码
    public static Answer verification()
    {

        bufferedImage = new BufferedImage(200, 35, BufferedImage.TYPE_INT_RGB);
        Graphics g = bufferedImage.getGraphics();
        Random rand = new Random();
        for (int i = 0; i < 20; i++)
        {
            Point p1 = new Point(rand.nextInt(200), rand.nextInt(30));
            Point p2 = new Point(rand.nextInt(200), rand.nextInt(30));
            g.drawLine(p1.x, p1.y, p2.x, p2.y);
        }
        g.setColor(Color.RED);
        g.setFont(new Font("楷体", Font.BOLD, 22));
        int plan = 2;
        switch (rand.nextInt(plan))
        {
        case 0:
            plan(g);
            break;
        case 1:
            plan1(g);
            break;
        default:
            break;
        }
        answer.setBufferedImage(bufferedImage);
        answer.setResult(result);
        g.dispose();
        return answer;
    }

    // 方案一
    private static void plan(Graphics g)
    {
        words = ReadTxt.read("/res/words.txt"); // 指定生成验证码问题的资源文件的路径
        Random rand = new Random();
        String first = String.valueOf(words.charAt(rand.nextInt(words.length())));
        String second = String.valueOf(words.charAt(rand.nextInt(words.length())));
        String third = String.valueOf(words.charAt(rand.nextInt(words.length())));
        g.drawString(first, rand.nextInt(40) + 20, rand.nextInt(12) + 15);
        g.drawString(second, rand.nextInt(40) + 80, rand.nextInt(12) + 15);
        g.drawString(third, rand.nextInt(40) + 140, rand.nextInt(12) + 15);
        result = first + second + third;
    }

    // 方案二
    private static void plan1(Graphics g)
    {
        words2 = ReadTxt.read("/res/words2.txt"); // 指定生成验证码问题的资源文件的路径
        Random rand = new Random();
        String first = String.valueOf(words2.charAt(rand.nextInt(words2.length() - 2)));
        String second = String.valueOf(words2.charAt(rand.nextInt(2) + 9));
        String third = String.valueOf(words2.charAt(rand.nextInt(words2.length() - 2)));
        g.drawString(first, rand.nextInt(30) + 20, rand.nextInt(12) + 15);
        g.drawString(second, rand.nextInt(40) + 60, rand.nextInt(12) + 15);
        g.drawString(third, rand.nextInt(30) + 110, rand.nextInt(12) + 15);
        g.drawString("=", rand.nextInt(40) + 150, rand.nextInt(12) + 15);
        if(second.equals("+"))
        {
            result = String.valueOf(Integer.valueOf(first) + Integer.valueOf(third)); 
        }else{
            result = String.valueOf(Integer.valueOf(first) - Integer.valueOf(third)); 
        }
    }

}

Read the file class required to generate the verification code

package ccnu.util;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

// 专门用于读取文件
public class ReadTxt
{
    public static String read(String path) // 根据指定路径path来读取它，并返回它所包含的内容
    {
        StringBuffer sb = new StringBuffer();
        try
        {
            BufferedReader br = new BufferedReader(new InputStreamReader(Verification.class.getResourceAsStream(path)));
            String temp = null;
            while(null != (temp = br.readLine()))
            {
                sb.append(temp);
            }
            br.close();
        } catch (IOException e)
        {
            e.printStackTrace();
        }
        return sb.toString();
    }

}

Get the information class contained in the generated verification code(Pattern, question)

package ccnu.util;

import java.awt.image.BufferedImage;

// 用于将生成的验证码的图案信息以及问题结果封装
public class Answer
{
    private BufferedImage bufferedImage = null; // 验证码图像
    private String result = null; // 验证码图像问题的答案

    public BufferedImage getBufferedImage()
    {
        return bufferedImage;
    }
    public void setBufferedImage(BufferedImage bufferedImage)
    {
        this.bufferedImage = bufferedImage;
    }
    public String getResult()
    {
        return result;
    }
    public void setResult(String result)
    {
        this.result = result;
    }

}

Verification code generation file words.txt
For example: Handong University School of Political Science and Law, Wuhan City, Hubei Province, China

Verification code generation file words2.txt
123456789 -

Prompt picture

##Login effect

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