删除数据层引用

public class UserService {
    private UserRepository userRepository;

    public UserService(UserRepository userRepository) {
        this.userRepository = userRepository;
    }

    public User getUserById(int id) {
        return userRepository.findById(id);
    }
}

public class UserService {
    public User getUserById(int id) {
        // 使用新的数据访问方式，例如JDBC
        Connection conn = null;
        PreparedStatement stmt = null;
        ResultSet rs = null;
        User user = null;

        try {
            conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/mydb", "user", "password");
            String sql = "SELECT * FROM users 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.setName(rs.getString("name"));
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            try {
                if (rs != null) rs.close();
                if (stmt != null) stmt.close();
                if (conn != null) conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }

        return user;
    }
}