有什么方法可以让悲观锁和乐观锁在Hibernate中都工作

Question

我有一个这样的实体

@Entity
@Table(name = "ACC_ACCOUNT_INFO")
@Getter
@Setter
public class AccountInfoEntity implements Serializable {

@GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "accountIdGenerator")
@SequenceGenerator(name = "accountIdGenerator", sequenceName = "SEQ_ACCOUNT")
@Id
@Column(name = "ID")
private long id;

@Column(name = "ACCOUNT_NO", nullable = false)
private String accountNo;

@Column(name = "ACCOUNT_TYPE", nullable = false)
@Enumerated(EnumType.STRING)
private AccountType accountType;

@Column(name = "ACCOUNT_NAME", nullable = false)
private String accountName;

@Column(name = "BANK_NAME", nullable = false)
private String bankName;

@Column(name = "EXPIRY_DATE", nullable = false)
private LocalDate expiryDate;

@Column(name = "STATUS", nullable = false)
private String accountStatus;

@Column(name = "PARENT_ACC_ID")
private Long parentAccountId;

@Column(name = "BALANCE", nullable = false)
private BigDecimal balance;

@Version
@Access(javax.persistence.AccessType.PROPERTY)
@Column(name = "VERSION")
private int version;

}

在我的场景中，可以同时更新帐户余额。因此，如果两个请求同时来更新同一帐户余额，其中一个请求成功，另一个请求获得乐观锁定。因此，我尝试用PESSIMSTIC_WRITE锁定模式更新帐户。但当并发请求到达时，乐观锁错误仍然存在。然后我从实体中删除了VERSION属性（乐观锁定），然后对于同一个帐户，所有并发请求都会成功。

现在我的问题是，是否可以同时使用两种锁定机制？

更新：对于PESSIMSTIC_WRITE锁定模式Hibernate的同一帐户的5个并发调用，生成如下查询

Hibernate: select * from acc_account_info accountinf0_ where accountinf0_.account_no=?
Hibernate: select * from acc_account_info accountinf0_ where accountinf0_.account_no=?
Hibernate: select * from acc_account_info accountinf0_ where accountinf0_.account_no=?
Hibernate: select * from acc_account_info accountinf0_ where accountinf0_.account_no=?
Hibernate: select * from acc_account_info accountinf0_ where accountinf0_.account_no=?


Hibernate: select id from acc_account_info where id =? and version =? for update
Hibernate: select id from acc_account_info where id =? and version =? for update
Hibernate: select id from acc_account_info where id =? and version =? for update
Hibernate: select id from acc_account_info where id =? and version =? for update
Hibernate: select id from acc_account_info where id =? and version =? for update

但如果锁定模式为PESSIMSTIC_FORCE_INCREMENT，则Hibernate不会生成更新查询集的选择。因此悲观锁无法在PESSIMSTIC_FORCE_INCREMENT模式下工作。

这是我的代码

public AccountInfoEntity findByAccNoPessimistic(String accountNo) {
    Query query = em.createQuery("From AccountInfoEntity where accountNo=:accountNo");
    query.setParameter("accountNo", accountNo);
    query.setLockMode(LockModeType.PESSIMISTIC_FORCE_INCREMENT);
    AccountInfoEntity result = (AccountInfoEntity) query.getSingleResult();
    em.refresh(result);
    return result;
}

Answer 1

当您并行检索具有LockModeType.PESSIMISTIC_WRITE的实体时，只有一个调用应该成功，其他调用应该被阻止。因此，奇怪的是，您面临乐观锁错误。

在任何情况下< code>LockModeType。悲观_强制_增量 @Version是推荐的方法，它让两种机制都就位。(即，默认情况下将有一个乐观锁，如果明确要求，则为悲观锁)。