Hibernate：LazyInitializationException：懒得初始化一个角色集合。无法初始化代理 - 没有会话

I have next error: nested exception is org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.example.Model.entities, could not initialize proxy - no Session

我有下一个错误:嵌套异常是org.hibernate.LazyInitializationException:懒得初始化一个角色集合:com.example.Model.entities,无法初始化代理 - 没有Session

My Model entity:

我的模型实体:

class Model {
...
    @OneToMany(fetch = FetchType.LAZY, mappedBy = "model", orphanRemoval = true)
    @Cascade(CascadeType.ALL)
    @Fetch(value = FetchMode.SUBSELECT)
    public Set<Entity> getEntities() {
        return entities;
    }

    public void addEntity(Entity entity) {
        entity.setModel(this);
        entities.add(entity);
    }

}

And I have a service class:

我有一个服务类:

@Service
@Transactional
class ServiceImpl implements Service {
    @Override
    public void process(Model model) {
        ...
        model.addEntity(createEntity());
        ...
    }
}

I'm calling service from another service method:

我正在使用其他服务方法调用服务:

@Override
@JmsListener(destination = "listener")
public void handle(final Message message) throws Exception {
    Model model = modelService.getById(message.getModelId());
    serviceImpl.process(model);
    modelService.update(model);
}

But when I'm trying to call this method I'm getting exception on line entities.add(entity); also the same exception occurs when I'm calling getEntities() on model . I've checked transaction manager and it's configured correctly and transaction exists on this step. Also I've checked tons of answers on * connected to this exception but nothing useful.

但是当我试图调用这个方法时,我会在线上实体上获得异常.add(entity);当我在模型上调用getEntities()时也会发生同样的异常。我已经检查了事务管理器并且它已正确配置,并且此步骤中存在事务。此外,我已经检查了连接到此异常的*上的大量答案,但没有任何用处。

What could be the cause of it?

可能是什么原因造成的?

2 个解决方案

#1

It seems that model is a detached entity.

模型似乎是一个独立的实体。

Try to merge and perform operations on a merge instance:

尝试合并并在合并实例上执行操作:

@Override
public void process(Model model) {
     ...
    Model mergedModel = session.merge(model);

    mergedModel.addEntity(createEntity());
    ...
}

#2

So as @Maciej Kowalski mentioned after first @Transactional read of my model it's already in deatached state and call to get entities from another @Transactional method failed with LazyInitializationException.

因此@Maciej Kowalski在第一次@Transactional读取我的模型后提到它已经处于deatached状态并且调用从另一个@Transactional方法获取实体失败了LazyInitializationException。

I've changed my service a bit to get model from database in the same transaction:

我已经改变了我的服务,以便在同一个事务中从数据库中获取模型:

@Service
@Transactional
class ServiceImpl implements Service {
    @Override
    public void process(long modelId) {
        ...
        Model model = modelDao.get(modelId);
        model.addEntity(createEntity());
        ...
    }
}

Now everything works as expected.

现在一切都按预期工作。

#1