Правильная работа с БД посредством Спринга

public List<Customer> findAll(){
 
    String sql = "SELECT * FROM CUSTOMER";
 
    List<Customer> customers = new ArrayList<Customer>();
 
    List<Map> rows = getJdbcTemplate().queryForList(sql);
    for (Map row : rows) {
        Customer customer = new Customer();
        customer.setCustId((Long)(row.get("CUST_ID")));
        customer.setName((String)row.get("NAME"));
        customer.setAge((Integer)row.get("AGE"));
        customers.add(customer);
    }
 
    return customers;
}

@Repository
public class UserDaoImpl implements UserDao {
 
    public static final String SQL_SELECT_USERS_BY_ID =
            "SELECT USERS_ID, LAST_NAME, SECOND_NAME, FIRST_NAME, LOGIN, PASSWD FROM USERS " +
            "WHERE USERS_ID = ?";
    public static final String SQL_SELECT_USERS =
            "SELECT USERS_ID, LAST_NAME, SECOND_NAME, FIRST_NAME, LOGIN, PASSWD FROM USERS";
 
    private final UserRowMapper rowMapper = new UserRowMapper();
 
    @Autowired
    private JdbcTemplate jdbcTemplate;
 
    @Override
    public User getUserById(long id) {
        try {
            return jdbcTemplate.queryForObject(SQL_SELECT_USERS_BY_ID,
                    new Object[] {id}, rowMapper);
        } catch (EmptyResultDataAccessException e) {
            return null;
        }
    }
 
    @Override
    public List<User> getAllUsers() {
        return jdbcTemplate.query(SQL_SELECT_USERS, rowMapper);
    }
 
    public static final class UserRowMapper implements RowMapper<User> {
 
        @Override
        public User mapRow(ResultSet rs, int rowNum) throws SQLException {
            User user = new User();
            user.setId(rs.getLong("USERS_ID"));
            user.setLastName(rs.getString("LAST_NAME"));
            user.setFirstName(rs.getString("FIRST_NAME"));
            user.setSecondName(rs.getString("SECOND_NAME"));
            user.setLogin(rs.getString("LOGIN"));
            user.setPassword(rs.getString("PASSWD"));
            return user;
        }
    }
}