小编sil*_*lea的帖子

我被分配了一个使用sqlite演示CRUD操作的任务。当我尝试从数据库中检索项目时，我的ResultSet似乎没有“ id”列。我很沮丧。

这是我的ContactRepository类。

public class ContactRepositoryJDBC implements ContactRepository {

    private static Connector connector = new Connector();

    ...

    public Contact getById(int id) throws SQLException {
        Contact contact = null;

        try (Connection conn = connector.getConnection();
            PreparedStatement statement = conn
                    .prepareStatement(SQL.GET_CONTACT_BY_ID)) {
            statement.setInt(1, id);
            try (ResultSet resultSet = statement.executeQuery()) {
                if (resultSet.next()) {
                    contact = new Contact();
                    contact.setId(resultSet.getInt("id"));
                    contact.setFirstName(resultSet.getString("first_name"));
                    contact.setSurname(resultSet.getString("surname"));
                    contact.setHomeNumber(resultSet.getString("home_number"));
                    contact.setCellNumber(resultSet.getString("cell_number"));
                    contact.setEmail(resultSet.getString("email"));
                }
            }
        }

        if (contact == null) {
            System.out.print("no contact with id " + id + " found : "); …