java - executeQuery() 返回空结果集

Question

我正在创建一个简单的应用程序，它使用 JDBC 从 MySQL 获取数据。我使用 dao 从数据库中获取数据。除了一个之外，所有其他都工作正常(所有 DAO 的代码都相同)。此外，我还手动提交 INSERT 和 UPDATE 方法。

即使我手动设置读提交隔离级别，Workbench 也会返回有效结果。

JDBCSessionDao创建方法:

public void create(Session session) throws SQLException{
        try(PreparedStatement ps = conn.prepareStatement(INSERT_SESSION)){
            conn.setAutoCommit(false);

            LocalTime start = session.getStartTime();
            LocalTime end = session.getEndTime();

            System.out.println(start + ", " + end);
            System.out.println(Time.valueOf(start) + ", " + Time.valueOf(end));

            ps.setTime(1, Time.valueOf(start));
            ps.setTime(2, Time.valueOf(end));
            ps.setDate(3, Date.valueOf(session.getDate()));
            ps.setLong(4, session.getMovieId());

            ps.executeUpdate();

            conn.commit();
            conn.setAutoCommit(true);
        }
        catch (SQLException e){
            logger.error(e.getMessage());
            conn.rollback();
        }
    }

JDBCSessionDao findByDate 方法

public List<Session> findByDate(LocalDate date) {
    List<Session> sessions = new ArrayList<>();
    SessionMapper mapper = new SessionMapper();

    try(PreparedStatement ps = conn.prepareStatement(SELECT_BY_DATE_ORDER_BY_TIME_ASC)){
        ps.setDate(1, Date.valueOf(date));

        ResultSet rs = ps.executeQuery();

        System.out.println(rs.getFetchSize());

        while(rs.next()){
            Session s = mapper.extractFromResultSet(rs);
            sessions.add(s);
        }
    }
    catch (SQLException e){
        logger.error(e.getMessage());
    }

    return sessions;
}

查询:

String SELECT_BY_DATE_ORDER_BY_TIME_ASC = "SELECT * FROM sessions WHERE session_date=? ORDER by start_time ASC";

JDBCDaoFactory getConnection() 方法:

private Connection getConnection(){
    String url = "jdbc:mysql://localhost:3306/cinemajee?useLegacyDatetimeCode=false&serverTimezone=Europe/Kiev";
    String user = "root";
    String password = "root";

    try{
        Class.forName("com.mysql.cj.jdbc.Driver");
        return DriverManager.getConnection(url, user, password);
    }
    catch (SQLException | ClassNotFoundException e){
        e.printStackTrace();
        throw new RuntimeException();
    }
}

工作台查询结果: query result

Answer 1

尝试修改代码中的查询。也许 session_date 参数不起作用。所以改变一下:

"SELECT * FROM sessions WHERE session_date=? ORDER by start_time ASC"'

对此:

"SELECT * FROM sessions ORDER by start_time ASC LIMIT 5"'