java - Spring JPA 无法在一个线程中正确处理多个事务

Question

我有以下代码片段。在我调用 BatchSettleService.batchSettleWork(Array.asList([1,2,3])) 之后。我发现DB中的账户余额只减少了1。 debug的结果是每次accountRepository.findByIdForUpdate(2)返回的都是原来的Account，没有在过去的循环中操作过任何变化。我已经尝试了 Isolation.SERIALIZABLE 级别，但结果是一样的。我使用的数据库是 MySQL 5.7.20 InnoDb Engine。 JPA 实现是 Hibernate。我预计账户余额会减少 3. 我对交易的理解有问题吗？提前致谢!

@Service
public class BatchSettleService {

    private Logger logger = LoggerFactory.getLogger(getClass());

    @Autowired
    private WorkSettleService workSettleService;

    public List<WorkSettleResponse> batchSettleWork(List<Long> workIds) {
        List<WorkSettleResponse> results= new ArrayList<>();
        for(Long workId:workIds) {
            try {
                results.add(workSettleService.settleWork(new WorkSettleRequest(workId)));
            } catch (WrappedException e) {
                results.add(new WorkSettleResponse(workId,e.getErrCode(),e.getMessage()));
                logger.error("Settle work failed for {}",workId,e);
            }
        }
        return results;
    }

}


   public class WorkSettleService{

        @Autowired
        private AccountRepository accountRepository;

        @Transactional(rollbackFor= {WorkSettleException.class,RuntimeException.class},propagation=Propagation.REQUIRES_NEW)
        public WorkSettleResponse settleWork(WorkSettleRequest req){
             Account account = accountRepository.findByIdForUpdate(2);
             Integer balance = account .getBalance();
             accountRepository.updateBalanceById(account.getId(),balance-1)
        }
    }


    public interface AccountRepository extends Repository<Account, Integer> {

        public Account findById(Integer id);

        @Lock(LockModeType.PESSIMISTIC_WRITE)
        @Query("select ac from Account a where a.id = ?1")
        public Account findByIdForUpdate(Integer id);

        @Modifying
        @Query("update Account a set a.balance = ?2 where a.id = ?1")
        public int updateBalanceById(Integer id,Integer balance);

}

Answer 1

这个案子已经解决了。使用 account.setBalance(balance-1) 而不是 accountRepository.updateBalanceById(account.getId(),balance-1)。我不知道为什么 @Modifying annoation 不更新 EM 缓存，而 @Query 从 EM 缓存中获取数据，这对于 Spring JPA 实现来说有点奇怪。