java - 调用 EntityManager.persist() 时出现未知实体

Question

我在 QuoteProjection.java 中有这个类:

package com.mycompany.myapp.query;

import com.mycompany.myapp.command.domain.ProjectedQuote;
import javax.persistence.EntityManager;

public class QuoteProjection {

    private final EntityManager entityManager;
.
.
.
    public void on(CreateSubmissionEvt evt) {
        ProjectedQuote projectedQuote = new ProjectedQuote(evt.getAggregateId(), evt.getJobNumber());
        entityManager.persist(projectedQuote); // error reference this line
    }

我在 myApi.kt 中定义了 ProjectedQuote:

package com.mycompany.myapp.command.domain

@Entity
@NamedQueries(
        NamedQuery(name = "ProjectedQuote.fetch",
                query = "SELECT q FROM ProjectedQuote q WHERE q.aggregateId LIKE CONCAT(:idStartsWith, '%') ORDER BY q.id"),
        NamedQuery(name = "ProjectedQuote.count",
                query = "SELECT COUNT(q) FROM ProjectedQuote q WHERE q.aggregateId LIKE CONCAT(:idStartsWith, '%')")
)
data class ProjectedQuote(@Id var aggregateId: String, var jobNumber : String) { constructor() : this("", "") }

运行时出现如下错误:

java.lang.IllegalArgumentException: Unknown entity:
com.mycompany.myapp.command.domain.ProjectedQuote
        at org.hibernate.internal.SessionImpl.firePersist(SessionImpl.java:787) ~hibernate-core-5.2.17.Final.jar!/:5.2.17.Final]
        at org.hibernate.internal.SessionImpl.persist(SessionImpl.java:768) ~[hibernate-core-5.2.17.Final.jar!/:5.2.17.Final]
.
.
.

根据下面 Lesiak 的回答，我尝试将 @EntityScan 添加到应用程序 Application.java:

package com.mycompany.myapp.query;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.domain.EntityScan;

@SpringBootApplication
@EntityScan(basePackages = {"com.mycompany.myapp.command.domain"})
public class Application {
  public static void main(String[] args) {
    SpringApplication.run(Application.class, args);
  }
}

...但现在我收到以下错误并且应用程序终止:

2019-04-16 15:34:54.265 ERROR 4212 --- [           main] o.s.boot.SpringApplication
          : Application run failed

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sagaStore' defined in class path resource [org/axonframework/springboot/autoconfig/JpaAutoConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.axonframework.modelling.saga.repository.jpa.JpaSagaStore]: Factory method 'sagaStore' threw exception; nested exception is java.lang.IllegalArgumentException: org.hibernate.hql.internal.ast.QuerySyntaxException: SagaEntry is not mapped [SELECT new org.axonframework.modelling.saga.repository.jpa.SerializedSaga(se.serializedSaga, se.sagaType, se.revision) FROM SagaEntry se WHERE se.sagaId = :sagaId]
        at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:590) ~[spring-beans-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1247) ~[spring-beans-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
.
.
.

错误消息中引用的 Sagas 是 Axon 框架的一部分。因此，通过对我的包裹执行 @EntityScan，它看起来好像导致它不扫描 Axon 包裹，也许吧？

我头大了。感谢您的帮助。

Answer 1

用@Entity注释你的类如何？

参见示例 https://docs.jboss.org/hibernate/annotations/3.5/reference/en/html/entity.html#entity-mapping-entity

更新

检查扫描了哪些实体。 https://springbootdev.com/2017/11/13/what-are-the-uses-of-entityscan-and-enablejparepositories-annotations/amp/

默认情况下，Spring Boot 将启用实体扫描并在@SpringBootApplication 所在的包(及其子包)中查找。如果您的配置在另一个包中有实体，请使用 @EntityScan

更新 2

经过一些调查，发现这个问题是非常特定于 Axon 的。

Axon 需要注册自己的实体，就像更新问题中提到的 SagaEntry 一样。它在 JpaAutoConfiguration 中注册这些实体为此，它使用自己的注释 @RegisterDefaultEntities不幸的是，如果您依赖默认的项目布局(包含您的应用程序的包的子包中的域模型)，它们的配置会很好地工作，但不适合 @EntityScan

检查问题 https://github.com/AxonFramework/AxonFramework/issues/245

我的建议是重新打包您的应用程序(如果您的应用程序包，则将实体移动到子包)并删除 @EntityScan

如果您喜欢冒险，您可以尝试扫描通过自定义注释扫描的相同包，但我不确定这是否会成功。