MongoDB 的 EclipseLink 配置

Question

我遇到以下异常：

java.lang.ClassCastException: class org.eclipse.persistence.sessions.DatabaseRecord cannot be cast to class org.eclipse.persistence.oxm.record.XMLRecord (org.eclipse.persistence.sessions.DatabaseRecord and org.eclipse.persistence.oxm.record.XMLRecord are in unnamed module of loader 'app')
 Cause: class org.eclipse.persistence.sessions.DatabaseRecord cannot be cast to class org.eclipse.persistence.oxm.record.XMLRecord (org.eclipse.persistence.sessions.DatabaseRecord and org.eclipse.persistence.oxm.record.XMLRecord are in unnamed module of loader 'app')

以下是配置： 持久性.xml：

<?xml version="1.0"?>
<persistence xmlns="https://jakarta.ee/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="3.0">
    <persistence-unit name="eclipselink-persistence-unit" transaction-type="RESOURCE_LOCAL">
        <description> This is a EclipseLink based Persistence Unit</description>
        <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
        <exclude-unlisted-classes>false</exclude-unlisted-classes>
        <properties>
            <property name="eclipselink.target-database" value="org.eclipse.persistence.nosql.adapters.mongo.MongoPlatform"/>
            <property name="eclipselink.nosql.connection-spec" value="org.eclipse.persistence.nosql.adapters.mongo.MongoConnectionSpec"/>
            <property name="eclipselink.nosql.property.mongo.port" value="27017"/>
            <property name="eclipselink.nosql.property.mongo.host" value="localhost"/>
            <property name="eclipselink.nosql.property.mongo.db" value="my_db"/>
            <property name="eclipselink.logging.level" value="FINE"/>
        </properties>
    </persistence-unit>
</persistence>

JPAUtil 创建 EntityManagerFactory 实例：

public class JPAUtil {
  public static final String persistenceUnitName = "eclipselink-persistence-unit";
  private static EntityManagerFactory factory;
  private static final Logger LOGGER = LoggerFactory.getLogger(JPAUtil.class);

  public static EntityManagerFactory getEntityManagerFactory(){
    if(factory != null && factory.isOpen()){
      return factory;
    }
    LOGGER.info("Creating EntityManager Factory........");
    factory = Persistence.createEntityManagerFactory(persistenceUnitName);
    return factory;
  }

  public static void closeEntityManagerFactory(){
    LOGGER.info("Closing EntityManager Factory........");
    if(factory != null && factory.isOpen()){
      factory.close();
    }
  }

}

以下是另一个类中的函数，用于从 MongoDB 中的集合中获取数据：

public List<Data> getAll() {
        EntityManager entityManager = JPAUtil.getEntityManagerFactory().createEntityManager();
        EntityTransaction transaction = entityManager.getTransaction();

        boolean operationCompleted = false;
        List<Data> listOfData = null;

        try{
            transaction.begin();

            List<Data> data = entityManager.createQuery("SELECT v FROM Data v")
                    .getResultList();
            LOGGER.info("Completed the Search Operation");
            operationCompleted = true;
            listOfData = data;
        }
        catch( Exception e) {
            if(e.getCause()!=null) {
                LOGGER.error("Exception(Fetch All): {}\n Cause: {}", e.getMessage(), e.getCause().getMessage());
            }
            else{
                if(e.getMessage() == null){
                    LOGGER.error("Exception(Fetch All): {}, No Message",String.valueOf(e));
                }
                else {
                    LOGGER.error("Exception(Fetch All): {}, With Message", e.getMessage());
                }
            }
        }
        finally {
            if(operationCompleted){
                if(transaction.isActive())transaction.commit();
            }
            else{
                if(transaction.isActive())transaction.rollback();
            }
            entityManager.close();
        }
        return listOfData;
    }
}

以下是数据实体（这里的Details是另一个实体）：

@Entity
@Getter
@Setter
@NoSql(dataType = "DATA", dataFormat = DataFormatType.MAPPED)
public class Data {

    @Id
    @Field(name = "_id")
    private String name;

    @OneToMany(fetch = FetchType.EAGER, cascade = CascadeType.ALL, orphanRemoval = true)
    @JoinField(name = "details", referencedFieldName = "_id")
    private List<Details> internalDetails;
}

当我尝试将数据保存在数据库中时，我可以没有任何问题。但我无法取回它。

Answer 1

我很笨。我没有仔细阅读文档。他们在文档中提到：

MongoDB – 支持 JPQL 和 Criteria 查询，但有一些限制：不支持联接、子选择、分组依据和某些数据库函数。

我使用了FetchType.EAGER，它正在进行复杂的查询。 我将其更改为 FetchType.LAZY 现在可以使用了。