使用Java书写，运用数据访问层、业务逻辑层、UI层三层架构设计完成用户管理模块，完成用户登录业务设计

好的，以下是一个简单的Java三层架构设计完成用户管理模块和用户登录业务：

1. 数据库设计

我们假设需要设计一个用户表，包括用户ID、用户名、密码、角色等字段。可以使用如下的SQL语句创建用户表：

CREATE TABLE user (
  id INT NOT NULL AUTO_INCREMENT,
  username VARCHAR(50) NOT NULL,
  password VARCHAR(50) NOT NULL,
  role VARCHAR(50) NOT NULL,
  PRIMARY KEY (id)
);

2. 数据访问层

在数据访问层，我们使用JDBC连接数据库，实现对用户表的CRUD操作。我们可以创建一个名为UserDAO的类，包含如下方法：

public class UserDAO {
    // 数据库连接信息
    private static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
    private static final String DB_URL = "jdbc:mysql://localhost:3306/test";
    private static final String USER = "root";
    private static final String PASS = "password";

    // 查询所有用户
    public List<User> findAll() {
        List<User> users = new ArrayList<>();
        Connection conn = null;
        Statement stmt = null;
        ResultSet rs = null;
        try {
            Class.forName(JDBC_DRIVER);
            conn = DriverManager.getConnection(DB_URL, USER, PASS);
            stmt = conn.createStatement();
            String sql = "SELECT id, username, password, role FROM user";
            rs = stmt.executeQuery(sql);
            while (rs.next()) {
                User user = new User();
                user.setId(rs.getInt("id"));
                user.setUsername(rs.getString("username"));
                user.setPassword(rs.getString("password"));
                user.setRole(rs.getString("role"));
                users.add(user);
            }
        } catch (Exception ex) {
            ex.printStackTrace();
        } finally {
            try {
                if (rs != null) {
                    rs.close();
                }
                if (stmt != null) {
                    stmt.close();
                }
                if (conn != null) {
                    conn.close();
                }
            } catch (SQLException ex) {
                ex.printStackTrace();
            }
        }
        return users;
    }

    // 根据ID查询用户
    public User findById(int id) {
        User user = null;
        Connection conn = null;
        PreparedStatement stmt = null;
        ResultSet rs = null;
        try {
            Class.forName(JDBC_DRIVER);
            conn = DriverManager.getConnection(DB_URL, USER, PASS);
            String sql = "SELECT id, username, password, role FROM user WHERE id=?";
            stmt = conn.prepareStatement(sql);
            stmt.setInt(1, id);
            rs = stmt.executeQuery();
            if (rs.next()) {
                user = new User();
                user.setId(rs.getInt("id"));
                user.setUsername(rs.getString("username"));
                user.setPassword(rs.getString("password"));
                user.setRole(rs.getString("role"));
            }
        } catch (Exception ex) {
            ex.printStackTrace();
        } finally {
            try {
                if (rs != null) {
                    rs.close();
                }
                if (stmt != null) {
                    stmt.close();
                }
                if (conn != null) {
                    conn.close();
                }
            } catch (SQLException ex) {
                ex.printStackTrace();
            }
        }
        return user;
    }

    // 添加用户
    public void add(User user) {
        Connection conn = null;
        PreparedStatement stmt = null;
        try {
            Class.forName(JDBC_DRIVER);
            conn = DriverManager.getConnection(DB_URL, USER, PASS);
            String sql = "INSERT INTO user (username, password, role) VALUES (?, ?, ?)";
            stmt = conn.prepareStatement(sql);
            stmt.setString(1, user.getUsername());
            stmt.setString(2, user.getPassword());
            stmt.setString(3, user.getRole());
            stmt.executeUpdate();
        } catch (Exception ex) {
            ex.printStackTrace();
        } finally {
            try {
                if (stmt != null) {
                    stmt.close();
                }
                if (conn != null) {
                    conn.close();
                }
            } catch (SQLException ex) {
                ex.printStackTrace();
            }
        }
    }

    // 修改用户
    public void update(User user) {
        Connection conn = null;
        PreparedStatement stmt = null;
        try {
            Class.forName(JDBC_DRIVER);
            conn = DriverManager.getConnection(DB_URL, USER, PASS);
            String sql = "UPDATE user SET username=?, password=?, role=? WHERE id=?";
            stmt = conn.prepareStatement(sql);
            stmt.setString(1, user.getUsername());
            stmt.setString(2, user.getPassword());
            stmt.setString(3, user.getRole());
            stmt.setInt(4, user.getId());
            stmt.executeUpdate();
        } catch (Exception ex) {
            ex.printStackTrace();
        } finally {
            try {
                if (stmt != null) {
                    stmt.close();
                }
                if (conn != null) {
                    conn.close();
                }
            } catch (SQLException ex) {
                ex.printStackTrace();
            }
        }
    }

    // 删除用户
    public void delete(int id) {
        Connection conn = null;
        PreparedStatement stmt = null;
        try {
            Class.forName(JDBC_DRIVER);
            conn = DriverManager.getConnection(DB_URL, USER, PASS);
            String sql = "DELETE FROM user WHERE id=?";
            stmt = conn.prepareStatement(sql);
            stmt.setInt(1, id);
            stmt.executeUpdate();
        } catch (Exception ex) {
            ex.printStackTrace();
        } finally {
            try {
                if (stmt != null) {
                    stmt.close();
                }
                if (conn != null) {
                    conn.close();
                }
            } catch (SQLException ex) {
                ex.printStackTrace();
            }
        }
    }
}

3. 业务逻辑层

在业务逻辑层，我们使用数据访问层提供的方法，实现对用户表的业务逻辑处理。我们可以创建一个名为UserService的类，包含如下方法：

public class UserService {
    private UserDAO userDAO;

    public UserService() {
        userDAO = new UserDAO();
    }

    // 查询所有用户
    public List<User> findAll() {
        return userDAO.findAll();
    }

    // 根据ID查询用户
    public User findById(int id) {
        return userDAO.findById(id);
    }

    // 添加用户
    public void add(User user) {
        userDAO.add(user);
    }

    // 修改用户
    public void update(User user) {
        userDAO.update(user);
    }

    // 删除用户
    public void delete(int id) {
        userDAO.delete(id);
    }

    // 验证用户登录信息
    public boolean login(String username, String password) {
        User user = userDAO.findByUsername(username);
        if (user != null && user.getPassword().equals(password)) {
            return true;
        }
        return false;
    }
}

4. UI层

在UI层，我们使用Swing框架实现用户管理模块的用户界面和登录界面。我们可以创建一个名为UserFrame的类，包含如下界面：

public class UserFrame extends JFrame {
    private UserService userService;

    private JTable userTable;
    private DefaultTableModel tableModel;

    private JTextField idField;
    private JTextField usernameField;
    private JTextField passwordField;
    private JTextField roleField;

    public UserFrame() {
        userService = new UserService();

        setTitle("用户管理");
        setSize(600, 400);
        setLocationRelativeTo(null);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        // 用户列表
        userTable = new JTable();
        tableModel = new DefaultTableModel(new Object[][]{}, new Object[]{"ID", "用户名", "角色"});
        userTable.setModel(tableModel);
        JScrollPane scrollPane = new JScrollPane(userTable);

        // 用户表单
        JPanel userPanel = new JPanel(new GridLayout(4, 2, 5, 5));
        idField = new JTextField(10);
        usernameField = new JTextField(10);
        passwordField = new JTextField(10);
        roleField = new JTextField(10);
        userPanel.add(new JLabel("ID:"));
        userPanel.add(idField);
        userPanel.add(new JLabel("用户名:"));
        userPanel.add(usernameField);
        userPanel.add(new JLabel("密码:"));
        userPanel.add(passwordField);
        userPanel.add(new JLabel("角色:"));
        userPanel.add(roleField);

        // 按钮
        JPanel buttonPanel = new JPanel(new FlowLayout(FlowLayout.RIGHT));
        JButton addButton = new JButton("添加");
        addButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                User user = new User();
                user.setUsername(usernameField.getText());
                user.setPassword(passwordField.getText());
                user.setRole(roleField.getText());
                userService.add(user);
                refreshTable();
            }
        });
        JButton updateButton = new JButton("修改");
        updateButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                User user = new User();
                user.setId(Integer.parseInt(idField.getText()));
                user.setUsername(usernameField.getText());
                user.setPassword(passwordField.getText());
                user.setRole(roleField.getText());
                userService.update(user);
                refreshTable();
            }
        });
        JButton deleteButton = new JButton("删除");
        deleteButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                int id = Integer.parseInt(idField.getText());
                userService.delete(id);
                refreshTable();
            }
        });
        buttonPanel.add(addButton);
        buttonPanel.add(updateButton);
        buttonPanel.add(deleteButton);

        // 窗口布局
        setLayout(new BorderLayout());
        add(scrollPane, BorderLayout.CENTER);
        add(userPanel, BorderLayout.NORTH);
        add(buttonPanel, BorderLayout.SOUTH);

        // 刷新用户列表
        refreshTable();
    }

    // 刷新用户列表
    private void refreshTable() {
        List<User> users = userService.findAll();
        tableModel.setRowCount(0);
        for (User user : users) {
            Object[] rowData = new Object[]{
                    user.getId(),
                    user.getUsername(),
                    user.getRole()
            };
            tableModel.addRow(rowData);
        }
    }

    public static void main(String[] args) {
        // 显示用户管理界面
        UserFrame userFrame = new UserFrame();
        userFrame.setVisible(true);

        // 显示登录界面
        LoginFrame loginFrame = new LoginFrame(userFrame);
        loginFrame.setVisible(true);
    }
}

其中，登录界面可以创建一个名为LoginFrame的类，包含如下界面：

public class LoginFrame extends JFrame {
    private UserService userService;
    private UserFrame userFrame;

    private JTextField usernameField;
    private JPasswordField passwordField;

    public LoginFrame(UserFrame userFrame) {
        userService = new UserService();
        this.userFrame = userFrame;

        setTitle("用户登录");
        setSize(300, 150);
        setLocationRelativeTo(null);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        // 登录表单
        JPanel loginPanel = new JPanel(new GridLayout(2, 2, 5, 5));
        usernameField = new JTextField(10);
        passwordField = new JPasswordField(10);
        loginPanel.add(new JLabel("用户名:"));
        loginPanel.add(usernameField);
        loginPanel.add(new JLabel("密码:"));
        loginPanel.add(passwordField);

        // 按钮
        JPanel buttonPanel = new JPanel(new FlowLayout(FlowLayout.RIGHT));
        JButton loginButton = new JButton("登录");
        loginButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                String username = usernameField.getText();
                String password = new String(passwordField.getPassword());
                if (userService.login(username, password)) {
                    userFrame.setVisible(true);
                    setVisible(false);
                } else {
                    JOptionPane.showMessageDialog(LoginFrame.this, "用户名或密码错误", "错误", JOptionPane.ERROR_MESSAGE);
                }
            }
        });
        buttonPanel.add(loginButton);

        // 窗口布局
        setLayout(new BorderLayout());
        add(loginPanel, BorderLayout.CENTER);
        add(buttonPanel, BorderLayout.SOUTH);
    }
}

5. 运行测试

我们可以在main方法中先创建登录界面，当用户登录成功后再创建用户管理界面，代码如下：

public static void main(String[] args) {
    // 显示用户管理界面
    UserFrame userFrame = new UserFrame();
    userFrame.setVisible(false);

    // 显示登录界面
    LoginFrame loginFrame = new LoginFrame(userFrame);
    loginFrame.setVisible(true);
}

6. 总结

以上是一个简单的Java三层架构设计完成用户管理模块和用户登录业务的例子。在实际开发中，还需要考虑错误处理、异常处理、性能优化、安全性等方面的问题。