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mysql - Hibernate，出现异常后不刷新Session的问题

问题描述

我有 Hibernate 和 JPA 存储库实现的问题。

我收到以下错误：

“发生异常后不要刷新会话”

它来自部分，当 -> 在我保存模型之前，我检查数据库中是否存在。

留言表：

@Entity
@Table(name="message")
public class Message {

    @Id
    @Column(name = "id")
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @Column(name = "type")
    private MessageType type;

    @Column(name = "date")
    private Timestamp date;

    @Column(name = "message")
    private String message;

    @ManyToOne(cascade= {CascadeType.PERSIST, CascadeType.MERGE,
            CascadeType.DETACH, CascadeType.REFRESH})
    @JoinColumn(name="user_id")
    private User User;

    //constructor, empty constructor, getter & setter

}

用户表：

@Entity
@Table(name = "user")
public class User {

    @Id
    @Column(name = "id")
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @Column(name = "city")
    private String city;

    @Column(name = "name")
    private String name;

    @OneToMany(mappedBy = "user",
               cascade = {CascadeType.PERSIST, CascadeType.MERGE,
                        CascadeType.DETACH, CascadeType.REFRESH})
    private List<Message> message;

    //constructor, empty constructor, getter & setter

}

服务：

@Service
@Transactional
public class MessageUserDataService implements MessageUserService {


public void saveToDatabase(String data, String type, String message) {
    long userId;
    if (data.containsKey(userCode)) {
        userId = findUserId(userCode);
    } 
    MessageData messageData = new MessageData();
    User user = UserSystemService.findByUserId(id);
    messageData.setUser(user);
    messageData.setType(type);
    messageData.setMessage(message);

    messageDataService.save(messageData);
}

public long findUserId(Long id) {
    try {
        User user = UserSystemService.findByUserId(id);
        return user.getId();
    } catch (Exception e) {
        log("findUserId->id: " + id);
        throw e;
    }
}

可能这就是问题所在 - 这是一个例外。会议仍然开放。当然，我在服务中有事务注释。

和执行日志：

29.07.2019 21:43:12org.hibernate.AssertionFailure: null id in com.test.app.model.Message entry (don't flush the Session after an exception occurs)
29.07.2019 21:43:12 at org.hibernate.event.internal.DefaultFlushEntityEventListener.checkId(DefaultFlushEntityEventListener.java:60)
29.07.2019 21:43:12 at org.hibernate.event.internal.DefaultFlushEntityEventListener.getValues(DefaultFlushEntityEventListener.java:175)
29.07.2019 21:43:12 at org.hibernate.event.internal.DefaultFlushEntityEventListener.onFlushEntity(DefaultFlushEntityEventListener.java:135)
29.07.2019 21:43:12 at org.hibernate.event.internal.AbstractFlushingEventListener.flushEntities(AbstractFlushingEventListener.java:216)
29.07.2019 21:43:12 at org.hibernate.event.internal.AbstractFlushingEventListener.flushEverythingToExecutions(AbstractFlushingEventListener.java:85)
29.07.2019 21:43:12 at org.hibernate.event.internal.DefaultAutoFlushEventListener.onAutoFlush(DefaultAutoFlushEventListener.java:44)
29.07.2019 21:43:12 at org.hibernate.internal.SessionImpl.autoFlushIfRequired(SessionImpl.java:1398)
29.07.2019 21:43:12 at org.hibernate.internal.SessionImpl.list(SessionImpl.java:1483)
29.07.2019 21:43:12 at org.hibernate.query.internal.AbstractProducedQuery.doList(AbstractProducedQuery.java:1445)
29.07.2019 21:43:12 at org.hibernate.query.internal.AbstractProducedQuery.list(AbstractProducedQuery.java:1414)
29.07.2019 21:43:12 at org.hibernate.query.internal.AbstractProducedQuery.getSingleResult(AbstractProducedQuery.java:1463)
29.07.2019 21:43:12 at org.springframework.data.jpa.repository.query.JpaQueryExecution$SingleEntityExecution.doExecute(JpaQueryExecution.java:214)
29.07.2019 21:43:12 at org.springframework.data.jpa.repository.query.JpaQueryExecution.execute(JpaQueryExecution.java:91)
29.07.2019 21:43:12 at org.springframework.data.jpa.repository.query.AbstractJpaQuery.doExecute(AbstractJpaQuery.java:136)
29.07.2019 21:43:12 at org.springframework.data.jpa.repository.query.AbstractJpaQuery.execute(AbstractJpaQuery.java:125)
29.07.2019 21:43:12 at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.doInvoke(RepositoryFactorySupport.java:590)
29.07.2019 21:43:12 at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.invoke(RepositoryFactorySupport.java:578)
29.07.2019 21:43:12 at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185)
29.07.2019 21:43:12 at org.springframework.data.projection.DefaultMethodInvokingMethodInterceptor.invoke(DefaultMethodInvokingMethodInterceptor.java:59)
29.07.2019 21:43:12 at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185)
29.07.2019 21:43:12 at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:294)
29.07.2019 21:43:12 at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:98)
29.07.2019 21:43:12 at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185)
29.07.2019 21:43:12 at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:139)
29.07.2019 21:43:12 at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185)
29.07.2019 21:43:12 at org.springframework.data.jpa.repository.support.CrudMethodMetadataPostProcessor$CrudMethodMetadataPopulatingMethodInterceptor.invoke(CrudMethodMetadataPostProcessor.java:135)
29.07.2019 21:43:12 at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185)
29.07.2019 21:43:12 at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92)
29.07.2019 21:43:12 at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185)
29.07.2019 21:43:12 at org.springframework.data.repository.core.support.SurroundingTransactionDetectorMethodInterceptor.invoke(SurroundingTransactionDetectorMethodInterceptor.java:61)
29.07.2019 21:43:12 at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185)
29.07.2019 21:43:12 at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:212)
29.07.2019 21:43:12 at com.test.app.model.service.UserService.findUserId(UserService.java:14)

标签： mysqlhibernatespring-bootspring-data-jpaflush

解决方案

在调用方法之前，您很可能在catch其他地方用块抑制了异常。findUserId()调用时会报告该错误，findUserId()因为这是 Hibernate 决定在实体上自动刷新的后续调用。com.test.app.model.Message

您应该考虑审查您的会话维护策略。如果它是会话绑定到请求线程的常见 Web 场景与您有一个独立应用程序使会话保持打开数小时的情况，则修复将有所不同。

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