在JPA实体监听器中注入spring bean

Question

我试图让JPA Entity Listener通过将其标记为@Configurable来了解spring上下文.但是注入的spring bean是null.能够使用相同的技术使JPA实体了解Spring上下文.我使用Spring(core和data-jpa)作为基础设施.有关如何使用JPA Entity Listeners或spring data-jpa实现此目的的任何想法？

@Configurable
@Scope("singleton")
public class AggregateRootListener {
    private static Logger log = LoggerFactory.getLogger(AggregateRootListener.class);

    @Autowired
    private EventHandlerHelper eventHandlerHelper;

    @PostPersist
    @PostUpdate
    public void publishEvents(BaseAggregateRoot aggregateRoot){
        log.info(aggregateRoot.getEvents().toString());
        aggregateRoot.getEvents().stream()
            .forEach(event -> {
                eventHandlerHelper.notify(event, aggregateRoot);
                log.info("Publishing " + event + " " + aggregateRoot.toString());
            });
    }
}

和BaseAggregateRoot代码

@Configurable
@Scope("prototype")
@MappedSuperclass
@EntityListeners(AggregateRootListener.class)
public abstract class  BaseAggregateRoot extends BaseDomain{
    public static enum AggregateStatus {
        ACTIVE, ARCHIVE
    }

    @EmbeddedId
    @AttributeOverrides({
          @AttributeOverride(name = "aggregateId", column = @Column(name = "ID", nullable = false))})
    protected AggregateId aggregateId;



    @Version
    private Long version;
}

Answer 1

事件监听器机制是JPA概念,由JPA提供程序实现.我不认为Spring会创建事件监听器类实例 - 它们是由JPA提供程序(Hibernate,EclipseLink等)创建的.因此,常规Spring注入不适用于事件侦听器类实例.这篇文章的作者似乎得出了同样的结论.

也就是说,我在JPA事件监听器中使用Spring托管bean.我使用的解决方案是为了在所有不由Spring管理的类中获取Spring bean实例而开发的.它涉及创建以下类:

@Component
public class SpringApplicationContext implements ApplicationContextAware {
  private static ApplicationContext CONTEXT;

  public void setApplicationContext(final ApplicationContext context)
              throws BeansException {
    CONTEXT = context;
  }

  public static <T> T getBean(Class<T> clazz) { return CONTEXT.getBean(clazz); }
}

此类在初始加载时缓存Spring应用程序上下文.然后使用上下文查找Spring托管bean.

然后使用类就这么简单SpringApplicationContext.getBean(FooService.class).

所有常见的Spring语义,例如bean生命周期,bean范围和传递依赖关系都得到了解决.