مشروع: طبقة DAO

// User.java public record User(long id, String name, String email, String role) { // مصنع اختصاري — لبناء مستخدم جديد بلا معرّف بعد public static User of(String name, String email, String role) { return new User(0, name, email, role); } }

import java.util.List; import java.util.Optional; // UserDao.java public interface UserDao { User save(User user); // INSERT؛ يُعيد المستخدم المحفوظ مع معرّفه التلقائي Optional<User> findById(long id); // SELECT بالمفتاح الأساسي Optional<User> findByEmail(String email); List<User> findAll(); List<User> findByRole(String role); boolean update(User user); // UPDATE؛ يُعيد true إذا تغيّر صف boolean deleteById(long id); // DELETE؛ يُعيد true إذا حُذف صف }

import javax.sql.DataSource; import java.sql.*; import java.util.ArrayList; import java.util.List; import java.util.Optional; // JdbcUserDao.java public class JdbcUserDao implements UserDao { private final DataSource dataSource; public JdbcUserDao(DataSource dataSource) { this.dataSource = dataSource; } // ---- دالة مساعدة خاصة ------------------------------------------------- private User mapRow(ResultSet rs) throws SQLException { return new User( rs.getLong("id"), rs.getString("name"), rs.getString("email"), rs.getString("role") ); } // ---- INSERT --------------------------------------------------------- @Override public User save(User user) { String sql = "INSERT INTO users (name, email, role) VALUES (?, ?, ?)"; try (Connection conn = dataSource.getConnection(); PreparedStatement ps = conn.prepareStatement(sql, Statement.RETURN_GENERATED_KEYS)) { ps.setString(1, user.name()); ps.setString(2, user.email()); ps.setString(3, user.role()); ps.executeUpdate(); try (ResultSet keys = ps.getGeneratedKeys()) { if (keys.next()) { return new User(keys.getLong(1), user.name(), user.email(), user.role()); } } throw new SQLException("INSERT لم يُعد مفتاحًا مولّدًا"); } catch (SQLException e) { throw new DataAccessException("فشل save", e); } } // ---- SELECT بالمفتاح الأساسي ------------------------------------------- @Override public Optional<User> findById(long id) { String sql = "SELECT id, name, email, role FROM users WHERE id = ?"; try (Connection conn = dataSource.getConnection(); PreparedStatement ps = conn.prepareStatement(sql)) { ps.setLong(1, id); try (ResultSet rs = ps.executeQuery()) { return rs.next() ? Optional.of(mapRow(rs)) : Optional.empty(); } } catch (SQLException e) { throw new DataAccessException("فشل findById", e); } } // ---- SELECT بالبريد الإلكتروني ------------------------------------------ @Override public Optional<User> findByEmail(String email) { String sql = "SELECT id, name, email, role FROM users WHERE email = ?"; try (Connection conn = dataSource.getConnection(); PreparedStatement ps = conn.prepareStatement(sql)) { ps.setString(1, email); try (ResultSet rs = ps.executeQuery()) { return rs.next() ? Optional.of(mapRow(rs)) : Optional.empty(); } } catch (SQLException e) { throw new DataAccessException("فشل findByEmail", e); } } // ---- SELECT الكل ------------------------------------------------------- @Override public List<User> findAll() { String sql = "SELECT id, name, email, role FROM users ORDER BY id"; try (Connection conn = dataSource.getConnection(); PreparedStatement ps = conn.prepareStatement(sql); ResultSet rs = ps.executeQuery()) { List<User> users = new ArrayList<>(); while (rs.next()) { users.add(mapRow(rs)); } return users; } catch (SQLException e) { throw new DataAccessException("فشل findAll", e); } } // ---- SELECT بالدور ----------------------------------------------------- @Override public List<User> findByRole(String role) { String sql = "SELECT id, name, email, role FROM users WHERE role = ?"; try (Connection conn = dataSource.getConnection(); PreparedStatement ps = conn.prepareStatement(sql)) { ps.setString(1, role); try (ResultSet rs = ps.executeQuery()) { List<User> users = new ArrayList<>(); while (rs.next()) { users.add(mapRow(rs)); } return users; } } catch (SQLException e) { throw new DataAccessException("فشل findByRole", e); } } // ---- UPDATE ------------------------------------------------------------ @Override public boolean update(User user) { String sql = "UPDATE users SET name = ?, email = ?, role = ? WHERE id = ?"; try (Connection conn = dataSource.getConnection(); PreparedStatement ps = conn.prepareStatement(sql)) { ps.setString(1, user.name()); ps.setString(2, user.email()); ps.setString(3, user.role()); ps.setLong(4, user.id()); return ps.executeUpdate() > 0; } catch (SQLException e) { throw new DataAccessException("فشل update", e); } } // ---- DELETE ------------------------------------------------------------ @Override public boolean deleteById(long id) { String sql = "DELETE FROM users WHERE id = ?"; try (Connection conn = dataSource.getConnection(); PreparedStatement ps = conn.prepareStatement(sql)) { ps.setLong(1, id); return ps.executeUpdate() > 0; } catch (SQLException e) { throw new DataAccessException("فشل deleteById", e); } } }

// DataAccessException.java public class DataAccessException extends RuntimeException { public DataAccessException(String message, Throwable cause) { super(message, cause); } }

// UserService.java public class UserService { private final UserDao userDao; public UserService(UserDao userDao) { this.userDao = userDao; } public User registerUser(String name, String email, String role) { userDao.findByEmail(email).ifPresent(existing -> { throw new IllegalStateException("البريد مسجّل مسبقًا: " + email); }); return userDao.save(User.of(name, email, role)); } public User getOrThrow(long id) { return userDao.findById(id) .orElseThrow(() -> new IllegalArgumentException("لا يوجد مستخدم بالمعرّف " + id)); } public List<User> admins() { return userDao.findByRole("ADMIN"); } }

import com.zaxxer.hikari.HikariConfig; import com.zaxxer.hikari.HikariDataSource; public class Main { public static void main(String[] args) { // 1. مجمّع الاتصالات (HikariCP) HikariConfig config = new HikariConfig(); config.setJdbcUrl("jdbc:mysql://localhost:3306/mydb"); config.setUsername("root"); config.setPassword("secret"); config.setMaximumPoolSize(10); var dataSource = new HikariDataSource(config); // 2. ربط الطبقات UserDao userDao = new JdbcUserDao(dataSource); UserService service = new UserService(userDao); // 3. استخدام الخدمة User alice = service.registerUser("Alice", "alice@example.com", "ADMIN"); System.out.println("تم الحفظ: " + alice); service.admins().forEach(System.out::println); dataSource.close(); } }