Java如何将数组中的变量分配给另一个数组

Question

好的，所以我正在尝试在 java swing 中制作银行应用程序的登录屏幕。我必须让用户在登录屏幕中输入他的登录名、密码和 ID；问题是用户可以输入任何 ID 并通过登录屏幕。BankGlowna() 是显示登录屏幕之后的窗口的方法。代码如下:

        Connection c = null;
        Statement stmt = null;

        int countLogin = 0;
        int countPwd = 0;
        int countIDs = 0;

        String[] logins = new String[50];
        String[] pwds = new String[50];
        String[] ids = new String[50];

        try {
            String url = "jdbc:sqlite:D:\\SQLiteDB\\Bank.db";
            c = DriverManager.getConnection(url);
            c.setAutoCommit(false);

            stmt = c.createStatement();
            ResultSet rs = stmt.executeQuery("SELECT * FROM Logins;");

            while (rs.next()) {
                id = rs.getString("IDLogin");
                login = rs.getString("Login");
                pwd = rs.getString("Password");

                if (countIDs < ids.length) {
                    ids[countIDs] = id;
                    countIDs++;
                }

                if (countLogin < logins.length) {
                    logins[countLogin] = login;
                    countLogin++;
                }

                if (countPwd < pwds.length) {
                    pwds[countPwd] = pwd;
                    countPwd++;
                }
            }
        }
        catch (Exception ex) {
            System.out.println(ex);
        }

        JFrame loginFrame = new JFrame("Bank");
        loginFrame.setSize(400, 400);

        JLabel loginLabel = new JLabel("Login:");
        loginLabel.setBounds(5, 10, 200, 20);

        JTextField loginText = new JTextField();
        loginText.setBounds(5, 30, 200 ,20);

        JLabel pwdLabel = new JLabel("Hasło: ");
        pwdLabel.setBounds(5, 50, 200 ,20);

        JPasswordField pwdField = new JPasswordField();
        pwdField.setBounds(5, 70, 200, 20);

        JLabel idLabel = new JLabel("ID:");
        idLabel.setBounds(5, 90, 200, 20);

        JTextField idTF = new JTextField();
        idTF.setBounds(5, 110, 200 ,20);

        JButton loginButton = new JButton("Zaloguj");
        loginButton.setBounds(5, 140, 200, 20);

        loginButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                loginChk = loginText.getText();
                pwdChk = new String(pwdField.getPassword());
                idChk = idTF.getText();

                for (int i = 0; i < logins.length; i++) {
                    if (loginText.getText().equals(logins[i])) {
                        for (int a = 0; a < pwds.length; a++) {
                            if (pwdChk.equals(pwds[a])) {
                                for (int c = 0; c < ids.length; c++) {
                                    if (idChk.equals(ids[c])) {
                                        idDoKonta = ids[c];
                                        loginFrame.dispose();
                                        BankGlowna();
                                    }
                                }
                            }
                        }
                    }
                }
            }
        });

        loginFrame.setVisible(true);
        loginFrame.setLayout(null);
        loginFrame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        loginFrame.add(loginLabel);
        loginFrame.add(loginText);
        loginFrame.add(pwdLabel);
        loginFrame.add(pwdField);
        loginFrame.add(loginButton);
        loginFrame.add(idLabel);
        loginFrame.add(idTF);
    }```

Answer 1

当您从数据库传输数据时，您应该将与每个用户关联的信息放在数组中的相同位置，因为它们位于同一行。因此，与 logins[0] 关联的密码和 ID 是 pwds[0] 和 ids[0]；因此，您可以在对用户进行身份验证时使用它。您的 ActionListener 代码:

@Override
            public void actionPerformed(ActionEvent e) {
                loginChk = loginText.getText();
                pwdChk = new String(pwdField.getPassword());
                idChk = idTF.getText();

                for (int i = 0; i < logins.length; i++) {
                    if (loginChk.equals(logins[i])) {
                        // Then EVERYTHING should be at index i
                        if (pwdChk.equals(pwds[i]) && idChk.equals(ids[i])) {
                           // user authenticated
                           idDoKonta = ids[i];
                           loginFrame.dispose();
                           BankGlowna();
                           return; // leave the function so you don't keep iterating through the loop
                        }
                    }
                }
            }