4.17

/**
 * function：站名查询
 */

public static String station(User user) {
    Connection connection = null;
    StringBuilder resultBuilder = new StringBuilder();
    Logger logger = Logger.getLogger("RouteLogger"); // 创建日志记录器

    try {
        connection = com.example.test_one.utils.JDBCUtils.getConn();

        if (connection != null) {
            String query = "SELECT * FROM station WHERE Starting_Station=?";

            try (PreparedStatement pstmt = connection.prepareStatement(query)) {
                pstmt.setString(1, user.getStarting_Station());

                try (ResultSet rs = pstmt.executeQuery()) {
                    boolean foundResult = false; // 用于标记是否找到结果
                    while (rs.next()) {
                        // 从结果集中获取 Line 列的值
                        String subwayLine = rs.getString("Line");
                        // 将查询结果拼接为字符串
                        resultBuilder.append("线路名：").append(subwayLine).append("\n");
                        foundResult = true; // 找到了结果
                    }

                    if (!foundResult) {
                        resultBuilder.append("未查询到结果\n"); // 在找不到结果时追加消息
                    }
                }
            }
        } else {
            // 处理数据库连接为null的情况
        }
    } catch (SQLException ex) {
        // 处理 SQL 异常
        logger.severe("SQL Exception occurred: " + ex.getMessage());
    } catch (Exception ex) {
        // 处理其他异常
        logger.severe("Exception occurred: " + ex.getMessage());
    } finally {
        // 关闭数据库连接
        if (connection != null) {
            try {
                connection.close();
            } catch (SQLException e) {
                logger.severe("Error closing connection: " + e.getMessage());
            }
        }
    }

    // 检查结果是否为空，为空则返回“未查询到结果”
    if (resultBuilder.length() == 0) {
        resultBuilder.append("未查询到结果\n");
    }

    return resultBuilder.toString();
}