在同一张表中插入多条记录的乐观锁定

Question

尝试使用乐观锁实现。所以我按照以下步骤

1. 在表中创建版本归档
2. 在实体类中定义相同的文件

实体如下所示

@Entity
@Table(name = "txn_customer")
public class TxnCustomer implements Serializable {
    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "TXN_ID")
    private Integer txnId;

    @Version
    private Integer version;

    @Temporal(TemporalType.DATE)
    @Column(name = "TXN_DATE")
    private Date txnDate;

    @Column(name = "CASHMEMO_NUMBER")
    private Long cashmemoNumber;

    @Column(name = "INVOICE_AMOUNT")
    private double invoiceAmount;
    
}   

现在我正在尝试使用 JPA 将 2 条记录插入到 txn_customer 表中。我有以下代码

@Transactional(propagation = Propagation.REQUIRED)
public TransactionResponseDTO saveTransaction(RequestDTO requestDTO) {
    TxnCustomer object1 = saveTxnCustomer(requestDTO);
    repo.save(object1);

    TxnCustomer object2 = saveTxnCustomer(requestDTO);
    repo.save(object2);
}   

在执行上面的代码时出现以下异常

Caused by: javax.persistence.RollbackException: Error while committing the transaction
    at org.hibernate.internal.ExceptionConverterImpl.convertCommitException(ExceptionConverterImpl.java:81) ~[hibernate-core-5.6.14.Final.jar:5.6.14.Final]
    at org.hibernate.engine.transaction.internal.TransactionImpl.commit(TransactionImpl.java:104) ~[hibernate-core-5.6.14.Final.jar:5.6.14.Final]
    at org.springframework.orm.jpa.JpaTransactionManager.doCommit(JpaTransactionManager.java:562) ~[spring-orm-5.3.24.jar:5.3.24]
    ... 72 common frames omitted
Caused by: java.lang.NullPointerException: Cannot invoke "java.lang.Integer.intValue()" because "current" is null
    at org.hibernate.type.IntegerType.next(IntegerType.java:70) ~[hibernate-core-5.6.14.Final.jar:5.6.14.Final]
    at org.hibernate.type.IntegerType.next(IntegerType.java:22) ~[hibernate-core-5.6.14.Final.jar:5.6.14.Final]
    at org.hibernate.engine.internal.Versioning.increment(Versioning.java:92) ~[hibernate-core-5.6.14.Final.jar:5.6.14.Final]
    at org.hibernate.event.internal.DefaultFlushEntityEventListener.getNextVersion(DefaultFlushEntityEventListener.java:430) ~[hibernate-core-5.6.14.Final.jar:5.6.14.Final]
    at org.hibernate.event.internal.DefaultFlushEntityEventListener.scheduleUpdate(DefaultFlushEntityEventListener.java:307) ~[hibernate-core-5.6.14.Final.jar:5.6.14.Final]
    at org.hibernate.event.internal.DefaultFlushEntityEventListener.onFlushEntity(DefaultFlushEntityEventListener.java:175) ~[hibernate-core-5.6.14.Final.jar:5.6.14.Final]
    at org.hibernate.event.service.internal.EventListenerGroupImpl.fireEventOnEachListener(EventListenerGroupImpl.java:107) ~[hibernate-core-5.6.14.Final.jar:5.6.14.Final]
    at org.hibernate.event.internal.AbstractFlushingEventListener.flushEntities(AbstractFlushingEventListener.java:229) ~[hibernate-core-5.6.14.Final.jar:5.6.14.Final]
    at org.hibernate.event.internal.AbstractFlushingEventListener.flushEverythingToExecutions(AbstractFlushingEventListener.java:93) ~[hibernate-core-5.6.14.Final.jar:5.6.14.Final]
    at org.hibernate.event.internal.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:39) ~[hibernate-core-5.6.14.Final.jar:5.6.14.Final]
    at org.hibernate.event.service.internal.EventListenerGroupImpl.fireEventOnEachListener(EventListenerGroupImpl.java:107) ~[hibernate-core-5.6.14.Final.jar:5.6.14.Final]
    at org.hibernate.internal.SessionImpl.doFlush(SessionImpl.java:1407) ~[hibernate-core-5.6.14.Final.jar:5.6.14.Final]
    at org.hibernate.internal.SessionImpl.managedFlush(SessionImpl.java:489) ~[hibernate-core-5.6.14.Final.jar:5.6.14.Final]
    at org.hibernate.internal.SessionImpl.flushBeforeTransactionCompletion(SessionImpl.java:3303) ~[hibernate-core-5.6.14.Final.jar:5.6.14.Final]
    at org.hibernate.internal.SessionImpl.beforeTransactionCompletion(SessionImpl.java:2438) ~[hibernate-core-5.6.14.Final.jar:5.6.14.Final]
    at org.hibernate.engine.jdbc.internal.JdbcCoordinatorImpl.beforeTransactionCompletion(JdbcCoordinatorImpl.java:449) ~[hibernate-core-5.6.14.Final.jar:5.6.14.Final]
    at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl.beforeCompletionCallback(JdbcResourceLocalTransactionCoordinatorImpl.java:183) ~[hibernate-core-5.6.14.Final.jar:5.6.14.Final]
    at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl.access$300(JdbcResourceLocalTransactionCoordinatorImpl.java:40) ~[hibernate-core-5.6.14.Final.jar:5.6.14.Final]
    at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl$TransactionDriverControlImpl.commit(JdbcResourceLocalTransactionCoordinatorImpl.java:281) ~[hibernate-core-5.6.14.Final.jar:5.6.14.Final]
    at org.hibernate.engine.transaction.internal.TransactionImpl.commit(TransactionImpl.java:101) ~[hibernate-core-5.6.14.Final.jar:5.6.14.Final]
    ... 73 common frames omitted

org.springframework.transaction.TransactionSystemException: Could not commit JPA transaction; nested exception is javax.persistence.RollbackException: Error while committing the transaction
    at org.springframework.orm.jpa.JpaTransactionManager.doCommit(JpaTransactionManager.java:571) ~[spring-orm-5.3.24.jar:5.3.24]
    at org.springframework.transaction.support.AbstractPlatformTransactionManager.processCommit(AbstractPlatformTransactionManager.java:743) ~[spring-tx-5.3.24.jar:5.3.24]
    at org.springframework.transaction.support.AbstractPlatformTransactionManager.commit(AbstractPlatformTransactionManager.java:711) ~[spring-tx-5.3.24.jar:5.3.24]
    at org.springframework.transaction.interceptor.TransactionAspectSupport.commitTransactionAfterReturning(TransactionAspectSupport.java:654) ~[spring-tx-5.3.24.jar:5.3.24]
    at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:407) ~[spring-tx-5.3.24.jar:5.3.24]
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:119) ~[spring-tx-5.3.24.jar:5.3.24]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.24.jar:5.3.24]
    at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:763) ~[spring-aop-5.3.24.jar:5.3.24]
    at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:708) ~[spring-aop-5.3.24.jar:5.3.24]

有人可以告诉我为什么我会遇到这个问题/或如何解决这个问题吗？