用java的gui和jdbc实现学生成绩管理，登陆页面实现注册和登陆，操作页面实现学生成绩的增删查改，并给出具体代码

好的，下面是一个简单的示例，实现了学生成绩管理系统的登陆页面、操作页面、数据库的设计和实现。

1. 登陆页面的代码如下：

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.sql.*;

public class LoginFrame extends JFrame implements ActionListener {
    private JLabel labelUser;
    private JLabel labelPwd;
    private JTextField fieldUser;
    private JPasswordField fieldPwd;
    private JButton buttonLogin;
    private JButton buttonRegister;

    public LoginFrame() {
        super("Login");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        labelUser = new JLabel("Username:");
        labelPwd = new JLabel("Password:");
        fieldUser = new JTextField(20);
        fieldPwd = new JPasswordField(20);
        buttonLogin = new JButton("Login");
        buttonRegister = new JButton("Register");

        JPanel panel = new JPanel(new GridLayout(3, 2));
        panel.add(labelUser);
        panel.add(fieldUser);
        panel.add(labelPwd);
        panel.add(fieldPwd);
        panel.add(buttonLogin);
        panel.add(buttonRegister);
        add(panel);

        buttonLogin.addActionListener(this);
        buttonRegister.addActionListener(this);

        pack();
        setLocationRelativeTo(null);
        setVisible(true);
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        if (e.getSource() == buttonLogin) {
            String user = fieldUser.getText();
            String pwd = new String(fieldPwd.getPassword());
            if (login(user, pwd)) {
                dispose();
                new MainFrame();
            } else {
                JOptionPane.showMessageDialog(null, "Invalid username or password.");
            }
        } else if (e.getSource() == buttonRegister) {
            String user = fieldUser.getText();
            String pwd = new String(fieldPwd.getPassword());
            if (register(user, pwd)) {
                JOptionPane.showMessageDialog(null, "Register successfully.");
            } else {
                JOptionPane.showMessageDialog(null, "Failed to register.");
            }
        }
    }

    private boolean login(String user, String pwd) {
        try {
            Class.forName("com.mysql.jdbc.Driver");
            Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", "password");
            PreparedStatement ps = conn.prepareStatement("SELECT * FROM user WHERE username = ? AND password = ?");
            ps.setString(1, user);
            ps.setString(2, pwd);
            ResultSet rs = ps.executeQuery();
            return rs.next();
        } catch (ClassNotFoundException | SQLException e) {
            e.printStackTrace();
            return false;
        }
    }

    private boolean register(String user, String pwd) {
        try {
            Class.forName("com.mysql.jdbc.Driver");
            Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", "password");
            PreparedStatement ps = conn.prepareStatement("INSERT INTO user (username, password) VALUES (?, ?)");
            ps.setString(1, user);
            ps.setString(2, pwd);
            int result = ps.executeUpdate();
            return result > 0;
        } catch (ClassNotFoundException | SQLException e) {
            e.printStackTrace();
            return false;
        }
    }

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

2. 操作页面的代码如下：

import javax.swing.*;
import javax.swing.table.DefaultTableModel;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.sql.*;

public class MainFrame extends JFrame implements ActionListener {
    private JButton buttonAdd;
    private JButton buttonDelete;
    private JButton buttonQuery;
    private JButton buttonUpdate;
    private JTable table;
    private DefaultTableModel model;

    public MainFrame() {
        super("Student Score Management");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        buttonAdd = new JButton("Add");
        buttonDelete = new JButton("Delete");
        buttonQuery = new JButton("Query");
        buttonUpdate = new JButton("Update");
        JPanel panelButtons = new JPanel(new FlowLayout());
        panelButtons.add(buttonAdd);
        panelButtons.add(buttonDelete);
        panelButtons.add(buttonQuery);
        panelButtons.add(buttonUpdate);
        add(panelButtons, BorderLayout.NORTH);

        model = new DefaultTableModel(new Object[][]{}, new String[]{"ID", "Name", "Score"});
        table = new JTable(model);
        JScrollPane scrollPane = new JScrollPane(table);
        add(scrollPane, BorderLayout.CENTER);

        buttonAdd.addActionListener(this);
        buttonDelete.addActionListener(this);
        buttonQuery.addActionListener(this);
        buttonUpdate.addActionListener(this);

        pack();
        setLocationRelativeTo(null);
        setVisible(true);
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        if (e.getSource() == buttonAdd) {
            addStudent();
        } else if (e.getSource() == buttonDelete) {
            deleteStudent();
        } else if (e.getSource() == buttonQuery) {
            queryStudents();
        } else if (e.getSource() == buttonUpdate) {
            updateStudent();
        }
    }

    private void addStudent() {
        String name = JOptionPane.showInputDialog("Input name:");
        String score = JOptionPane.showInputDialog("Input score:");
        try {
            Class.forName("com.mysql.jdbc.Driver");
            Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", "password");
            PreparedStatement ps = conn.prepareStatement("INSERT INTO student (name, score) VALUES (?, ?)");
            ps.setString(1, name);
            ps.setString(2, score);
            int result = ps.executeUpdate();
            if (result > 0) {
                JOptionPane.showMessageDialog(null, "Add successfully.");
            } else {
                JOptionPane.showMessageDialog(null, "Failed to add.");
            }
        } catch (ClassNotFoundException | SQLException e) {
            e.printStackTrace();
            JOptionPane.showMessageDialog(null, "Failed to add.");
        }
    }

    private void deleteStudent() {
        int row = table.getSelectedRow();
        if (row < 0) {
            JOptionPane.showMessageDialog(null, "Please select a row to delete.");
            return;
        }
        int id = (int) model.getValueAt(row, 0);
        try {
            Class.forName("com.mysql.jdbc.Driver");
            Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", "password");
            PreparedStatement ps = conn.prepareStatement("DELETE FROM student WHERE id = ?");
            ps.setInt(1, id);
            int result = ps.executeUpdate();
            if (result > 0) {
                JOptionPane.showMessageDialog(null, "Delete successfully.");
            } else {
                JOptionPane.showMessageDialog(null, "Failed to delete.");
            }
        } catch (ClassNotFoundException | SQLException e) {
            e.printStackTrace();
            JOptionPane.showMessageDialog(null, "Failed to delete.");
        }
    }

    private void queryStudents() {
        try {
            Class.forName("com.mysql.jdbc.Driver");
            Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", "password");
            PreparedStatement ps = conn.prepareStatement("SELECT * FROM student");
            ResultSet rs = ps.executeQuery();
            model.setRowCount(0);
            while (rs.next()) {
                int id = rs.getInt("id");
                String name = rs.getString("name");
                String score = rs.getString("score");
                model.addRow(new Object[]{id, name, score});
            }
        } catch (ClassNotFoundException | SQLException e) {
            e.printStackTrace();
        }
    }

    private void updateStudent() {
        int row = table.getSelectedRow();
        if (row < 0) {
            JOptionPane.showMessageDialog(null, "Please select a row to update.");
            return;
        }
        int id = (int) model.getValueAt(row, 0);
        String name = JOptionPane.showInputDialog("Input name:");
        String score = JOptionPane.showInputDialog("Input score:");
        try {
            Class.forName("com.mysql.jdbc.Driver");
            Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", "password");
            PreparedStatement ps = conn.prepareStatement("UPDATE student SET name = ?, score = ? WHERE id = ?");
            ps.setString(1, name);
            ps.setString(2, score);
            ps.setInt(3, id);
            int result = ps.executeUpdate();
            if (result > 0) {
                JOptionPane.showMessageDialog(null, "Update successfully.");
            } else {
                JOptionPane.showMessageDialog(null, "Failed to update.");
            }
        } catch (ClassNotFoundException | SQLException e) {
            e.printStackTrace();
            JOptionPane.showMessageDialog(null, "Failed to update.");
        }
    }

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

3. 数据库的设计和实现

学生信息表的设计如下：

CREATE TABLE student (
  id INT PRIMARY KEY AUTO_INCREMENT,
  name VARCHAR(20),
  score INT
);

用户信息表的设计如下：

CREATE TABLE user (
  id INT PRIMARY KEY AUTO_INCREMENT,
  username VARCHAR(20),
  password VARCHAR(20)
);

需要注意的是，上述代码中的数据库连接信息需要根据实际情况进行修改。