Question

我有一个MDB，它使用JPA调用Singleton EJB来维护hourlyTotals。我收到StaleObjectStateException：Row被另一个事务更新或删除

实体Bean代码

@Entity
@Table(name = "hour_db")
public class HourlyTotalEntity {
    @Id
    private Date transactionTime;

    @Column(name="success_count")
    private long  successCount;

    @Version int version;


    public Date getTransactionTime() {
        return transactionTime;
    }

    public void setTransactionTime(Date transactionTime) {
        this.transactionTime = transactionTime;
    }

    public void setSuccessCount(long successCount)
    {
        this.successCount = successCount;
    }
    public long getSuccessCount()
    {
        return successCount;
    }

    public int getVersion() {
        return version;
    }

    public void setVersion(int version) {
        this.version = version;
    }
}

EJB代码

@Singleton
@ConcurrencyManagement(ConcurrencyManagementType.CONTAINER)
@Lock(LockType.READ)
public class HourlyTotalEJB {
    @PersistenceContext (unitName="DashboardJPA")
    private EntityManager em;

    public void create(Date transactionTime) throws Exception
    {
        transactionTime = trim(transactionTime);
        HourlyTotalEntity entity = em.find(HourlyTotalEntity.class, transactionTime,LockModeType.OPTIMISTIC_FORCE_INCREMENT);
        if(entity == null)
        {
            entity = new HourlyTotalEntity();
            entity.setTransactionTime(transaction);
            entity.setSuccessCount(0);
        }

        entity.setAuthSuccessCount(entity.getAuthSuccessCount() + 1);
        em.persist(entity);
        em.flush();
        em.clear();
    }

    private Date trim(Date date) 
    {
         Calendar calendar = Calendar.getInstance();
         calendar.setTime(date);
         calendar.set(Calendar.MINUTE, 0);
         calendar.set(Calendar.MILLISECOND, 0);
         calendar.set(Calendar.SECOND, 0);
         return calendar.getTime();
    }
}

MDB在onMessage（消息消息）方法上调用create（transactionTime）。在大量转换期间，方法create（transcationTime）将由MDB同时调用并导致StaleObjectStateException：Row被另一个事务更新或删除

如何解决上述问题？

Answer 1

您正在使用paper，这允许多个线程同时调用该方法。由于{{1}}方法不是只读的，因此应使用写锁定。

Singleton EJB，JPA并发访问

1 个答案: