解决Spring或SpringBoot开启事务以后无法返回自增主键的问题

Spring或SpringBoot开启事务以后无法返回自增主键

场景：保存订单和订单详情，订单详情需要订单id，数据库中的订单表是自增主键，开启事务后，导致订单主键无法返回

1、开启事务前（以下代码只是样例，实际可能无法运行）

OrderMapper.xml配置

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="cn.test.mapper.OrderMapper" >
 <!-- 创建商品订单 -->
 <insert id="createGoodsOrder" parameterType="cn.test.pojo.dto.GoodsOrderDTO" useGeneratedKeys="true" keyProperty="orderId">
   INSERT INTO goods_order (
       order_no, shop_id, account_id, total_original_price, total_discount_price, total_price, order_status, order_source, goods_statement_no, create_time
   ) VALUES (
       #{orderNo}, #{shopId}, #{accountId}, #{totalOriginalPrice}, #{totalDiscountPrice}, #{totalPrice}, #{orderStatus}, #{orderSource}, #{goodsStatementNo}, #{createTime}
   )
 </insert>
 <!-- 创建商品订单详情 -->
 <insert id="createGoodsOrderDetail" parameterType="cn.test.pojo.dto.GoodsOrderDetailDTO" >
   INSERT INTO goods_order_detail (
       order_id, goods_sku_id, goods_num, original_price, discount_price, price, create_time
   ) VALUES (
       #{orderId}, #{skuId}, #{goodsNum}, #{originalPrice}, #{discountPrice}, #{price}, #{createTime}
   )
 </insert>
</mapper>

OrderMapper.java

package cn.test.mapper;
import cn.test.pojo.dto.GoodsOrderDTO;
import cn.test.pojo.dto.GoodsOrderDetailDTO;
import org.apache.ibatis.annotations.Mapper;
@Mapper
public interface OrderMapper {
   /**
    * 创建商品订单
    *
    * @param goodsOrderDTO
    * @return
    */
   void createGoodsOrder(GoodsOrderDTO goodsOrderDTO);
   /**
    * 创建商品订单详情
    *
    * @param goodsOrderDetailDTO
    */
   void createGoodsOrderDetail(GoodsOrderDetailDTO goodsOrderDetailDTO);
}

OrderService.java

package cn.test.service;
import cn.test.pojo.vo.CreateGoodsOrderVO;
import cn.tesst.pojo.bo.CreateOrderBO;
public interface OrderService {
   /**
    * 创建商品订单
   * @param createOrderBO
   * @return
   */
  CreateGoodsOrderVO createGoodsOrder(CreateOrderBO createOrderBO);  
}

OrderServiceImpl.java

package cn.test.service.impl;
import cn.test.pojo.vo.CreateGoodsOrderVO;
import cn.test.pojo.bo.CreateOrderBO;
import cn.test.utils.OrdersUtil;
import cn.test.constant.enums.OrderStatusEnums;
@Service
public class OrderServiceImpl implements OrderService {
  /**
   * 创建商品订单
   * @param createOrderBO
   * @return
   */
  @Override
  public CreateGoodsOrderVO createGoodsOrder(CreateOrderBO createOrderBO) {
      // 1 生成订单
      GoodsOrderDTO goodsOrderDTO = new GoodsOrderDTO();
      // 1.1 生成订单号
      String orderNo = orderPrefix + OrdersUtil.createOrderNo();
      // 1.2 封装订单实体类
      goodsOrderDTO.setOrderNo(orderNo);
      goodsOrderDTO.setShopId(shopId);
      goodsOrderDTO.setAccountId(createOrderBO.getAccountId());
      // 数据库按分处理
      goodsOrderDTO.setTotalPrice(totalPrice);
      goodsOrderDTO.setTotalOriginalPrice(totalOriginalPrice);
      goodsOrderDTO.setTotalDiscountPrice(totalOriginalPrice - totalPrice);
      goodsOrderDTO.setOrderSource(createOrderByShopBO.getOrderSource());
      goodsOrderDTO.setOrderStatus(OrderStatusEnums.CREATE_ORDER_SUCCESS.getCode());
      goodsOrderDTO.setGoodsStatementNo(statementNo);
      goodsOrderDTO.setCreateTime(dateString);
      // 1.3 创建订单
      orderMapper.createGoodsOrder(goodsOrderDTO);

// 2 封装订单详情
      GoodsOrderDetailDTO goodsOrderDetailDTO = new GoodsOrderDetailDTO();
      goodsOrderDetailDTO.setOrderId(goodsOrderDTO.getOrderId());//不开启事务可以获取到订单自增主键
      goodsOrderDetailDTO.setSkuId(skuId);
      goodsOrderDetailDTO.setGoodsNum(buyCounts);
      goodsOrderDetailDTO.setOriginalPrice(originalPrice);
      goodsOrderDetailDTO.setDiscountPrice(originalPrice - price);
      goodsOrderDetailDTO.setPrice(price);
      goodsOrderDetailDTO.setCreateTime(dateString);
      // TODO  查询库存、减库存
      // 2.1创建订单详情
      orderMapper.createGoodsOrderDetail(goodsOrderDetailDTO);

// 3 返回订单实体类
      CreateGoodsOrderVO createGoodsOrderVO = new CreateGoodsOrderVO();
      createGoodsOrderVO.setOrderNo(orderNo);
      createGoodsOrderVO.setTotalPrice(totalPrice);
      createGoodsOrderVO.setCreateTime(dateString);
      return createGoodsOrderVO;
  }
}

2、开启事务后（只修改了OrderMapper.xml和OrderServiceImpl.java）

OrderMapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="cn.test.mapper.OrderMapper" >

<!-- 创建商品订单 -->
  <insert id="createGoodsOrder" parameterType="cn.test.pojo.dto.GoodsOrderDTO" >
    <selectKey resultType="java.lang.Integer" keyProperty="orderId">
     SELECT LAST_INSERT_ID()
   </selectKey>
   INSERT INTO goods_order (
       id,order_no, shop_id, account_id, total_original_price, total_discount_price, total_price, order_status, order_source, goods_statement_no, create_time
   ) VALUES (
       #{orderId},#{orderNo}, #{shopId}, #{accountId}, #{totalOriginalPrice}, #{totalDiscountPrice}, #{totalPrice}, #{orderStatus}, #{orderSource}, #{goodsStatementNo}, #{createTime}
   )
 </insert>

<!-- 创建商品订单详情 -->
 <insert id="createGoodsOrderDetail" parameterType="cn.test.pojo.dto.GoodsOrderDetailDTO" >
   INSERT INTO goods_order_detail (
       order_id, goods_sku_id, goods_num, original_price, discount_price, price, create_time
   ) VALUES (
       #{orderId}, #{skuId}, #{goodsNum}, #{originalPrice}, #{discountPrice}, #{price}, #{createTime}
   )
 </insert>
</mapper>

OrderServiceImpl.java

package cn.test.service.impl;
import cn.test.pojo.vo.CreateGoodsOrderVO;
import cn.test.pojo.bo.CreateOrderBO;
import cn.test.utils.OrdersUtil;
import cn.test.constant.enums.OrderStatusEnums;
@Service
public class OrderServiceImpl implements OrderService {
   /**
    * 创建商品订单
    * @param createOrderBO
    * @return
    */
   @Transactional(propagation = Propagation.REQUIRED, rollbackFor = Exception.class)
   @Override
   public CreateGoodsOrderVO createGoodsOrder(CreateOrderBO createOrderBO) {
       // 1 生成订单
       GoodsOrderDTO goodsOrderDTO = new GoodsOrderDTO();
       // 1.1 生成订单号
       String orderNo = orderPrefix + OrdersUtil.createOrderNo();
       // 1.2 封装订单实体类
       goodsOrderDTO.setOrderNo(orderNo);
       goodsOrderDTO.setShopId(shopId);
       goodsOrderDTO.setAccountId(createOrderBO.getAccountId());
       // 数据库按分处理
       goodsOrderDTO.setTotalPrice(totalPrice);
       goodsOrderDTO.setTotalOriginalPrice(totalOriginalPrice);
       goodsOrderDTO.setTotalDiscountPrice(totalOriginalPrice - totalPrice);
       goodsOrderDTO.setOrderSource(createOrderByShopBO.getOrderSource());
       goodsOrderDTO.setOrderStatus(OrderStatusEnums.CREATE_ORDER_SUCCESS.getCode());
       goodsOrderDTO.setGoodsStatementNo(statementNo);
       goodsOrderDTO.setCreateTime(dateString);
       // 1.3 创建订单
       orderMapper.createGoodsOrder(goodsOrderDTO);

// 2 封装订单详情
       GoodsOrderDetailDTO goodsOrderDetailDTO = new GoodsOrderDetailDTO();
       goodsOrderDetailDTO.setOrderId(goodsOrderDTO.getOrderId());
       goodsOrderDetailDTO.setSkuId(skuId);
       goodsOrderDetailDTO.setGoodsNum(buyCounts);
       goodsOrderDetailDTO.setOriginalPrice(originalPrice);
       goodsOrderDetailDTO.setDiscountPrice(originalPrice - price);
       goodsOrderDetailDTO.setPrice(price);
       goodsOrderDetailDTO.setCreateTime(dateString);
       // TODO  查询库存、减库存
       // 2.1创建订单详情
       orderMapper.createGoodsOrderDetail(goodsOrderDetailDTO);

// 3 返回订单实体类
       CreateGoodsOrderVO createGoodsOrderVO = new CreateGoodsOrderVO();
       createGoodsOrderVO.setOrderNo(orderNo);
       createGoodsOrderVO.setTotalPrice(totalPrice);
       createGoodsOrderVO.setCreateTime(dateString);
       return createGoodsOrderVO;
   }    
}

OrderServiceImpl.java中添加事务后，需要在OrderMapper.xml使用 SELECT LAST_INSERT_ID()。

SpringBoot整合MyBatis获得插入数据后的主键，返回的一直是1(已解决)

MyBatis如何获得自增主键id，此处我不再叙述，网上有很多，这里就记录一下我遇到的问题。

先看一下我获得主键的部分SQL代码：

<insert id="save" parameterType="com.test.domain.CardDo"

keyProperty="cardId" useGeneratedKeys="true" >

insert into test
        <trim prefix="(" suffix=")" suffixOverrides=",">
        ......

我采用keyProperty的方式获取主键，我的实体类上也有对应的属性cardId，而我数据库的主键card_id也是自增的，但是获得的值一直是1？！！！

em…难道是我启动项目的姿势不对？要不我换个妖娆的姿势启动看看？莫非代码也看脸？

几经周转才发现原来是因为我service层获得主键id的方式不对，下面是我错误的写法：

@Override
@Transactional
public int save(CardDo cardDo,Long personId) {
       PersonDo personDo=new PersonDo();

//看见了吗，就是这句代码，这是错误的获取id的方式！错误的！错误的！
       Long cardId=cardDao.save(cardDo);

personDo.setCardId(cardId);
       personDo.setPersonId(personId);
       return personDao.update(personDo);
}

关键就在上面那句有注释的代码，save方法返回的是影响行数而不是主键id，实际上，在我们向数据库插入数据，获得此条数据的主键后是存储在我们的实体类中的，至于存储在实体类的哪一个属性中，那就要看keyProperty设置的值是什么了。

所以获得主键直接用这个实体类对应的属性的get方法获得就好了。

如下贴出我正确的代码：

@Override
@Transactional
public int save(CardDo cardDo,Long personId) {
       PersonDo personDo=new PersonDo();
       //插入数据
       cardDao.save(cardDo);

//获取主键
       Long cardId=cardDo.getCardId()

PersonDo .setCardId(cardId);
       PersonDo .setPersonId(personId);
       return personDao.update(PersonDo);
}

来源：https://www.cnblogs.com/guduershi/p/14808716.html