CREATE TABLE `order_cancel_freight_record` ( `id` bigint unsigned NOT NULL AUTO_INCREMENT, `created_at` datetime(3) DEFAULT NULL, `order_id` bigint unsigned NOT NULL COMMENT '订单号', `freight_amount` decimal(12,2) NOT NULL DEFAULT '0.00' COMMENT '订单运费', `operation` varchar(50) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL DEFAULT '' COMMENT '操作人', `approval_no` varchar(50) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL DEFAULT '' COMMENT '审批单号', `remark` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL DEFAULT '' COMMENT '备注', PRIMARY KEY (`id`) USING BTREE, KEY `order_id` (`order_id`) USING BTREE ) ENGINE=InnoDB AUTO_INCREMENT=276 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci ROW_FORMAT=DYNAMIC COMMENT='订单免除运费记录';根据表结构生成java的实体类，持久层，业务层，并添加注释

好的，我可以帮您生成相应的代码，以下是生成的代码，其中注释仅供参考：

实体类：

import java.math.BigDecimal;
import java.util.Date;

/**
 * 订单免除运费记录实体类
 */
public class OrderCancelFreightRecord {

    /** 自增主键 */
    private Long id;

    /** 创建时间 */
    private Date createdAt;

    /** 订单号 */
    private Long orderId;

    /** 订单运费 */
    private BigDecimal freightAmount;

    /** 操作人 */
    private String operation;

    /** 审批单号 */
    private String approvalNo;

    /** 备注 */
    private String remark;

    // getter 和 setter 方法
}

持久层：

import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Param;

/**
 * 订单免除运费记录持久层接口
 */
@Mapper
public interface OrderCancelFreightRecordMapper {

    /**
     * 新增订单免除运费记录
     * @param record 订单免除运费记录
     */
    void insert(OrderCancelFreightRecord record);

    /**
     * 根据订单号查询订单免除运费记录
     * @param orderId 订单号
     * @return 订单免除运费记录
     */
    OrderCancelFreightRecord selectByOrderId(@Param("orderId") Long orderId);

    // 其他常用的持久层方法
}

业务层：

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

/**
 * 订单免除运费记录业务层实现类
 */
@Service
public class OrderCancelFreightRecordServiceImpl implements OrderCancelFreightRecordService {

    @Autowired
    private OrderCancelFreightRecordMapper orderCancelFreightRecordMapper;

    @Override
    @Transactional(rollbackFor = Exception.class)
    public void insert(OrderCancelFreightRecord record) {
        orderCancelFreightRecordMapper.insert(record);
    }

    @Override
    public OrderCancelFreightRecord selectByOrderId(Long orderId) {
        return orderCancelFreightRecordMapper.selectByOrderId(orderId);
    }

    // 其他常用的业务层方法
}

希望这份代码可以帮助到您！