带有OneToOne主键/外键类型关系的JPA Hibernate空指针异常

Question

我正在尝试构建一个小原型，我遇到了很多麻烦。

问题涉及两个实体。但要理解它，我需要描述其他一些。

就数据库结构而言，可以描述如下：

Person
----------------
id   Integer PK
surname VARCHAR 
givenNames VARCHAR

TypedIdentifier
----------------
idCode  VARCHAR PK FK (IdType.code)
idVal   VARCHAR PK
person  Integer FK  (Person.id)

IdType
------
code   VARCHAR PK

IdDescription
----------
code   VARCHAR PK FK   (IdType.code)
category VARCHAR 
name    VARCHAR

我的问题出现在表IdDescription和IdType 之间的 关系中。

基本上，IdType表应该包含一个列，即主键（唯一）和辅助表（IdDescription），它描述了id-type，应该有一个该列的外键。

指导我设计数据库的两个要点：

1. IdType.code在它自己的单独表中，因为我想将Id与IdDescription隔离（从Java结构的角度来看）
2. 因为两个表TypedIdentifier和IdDescription都需要引用IdType，所以我只能在THOSE表中对IdType进行引用/关系注释（在IdType本身中没有）。

我的Java代码如下所示：

人

@MappedSuperclass
public class Person implements Serializable
{
    /**
     * internal unique identifier
     */
    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    public Integer id;

    /**
     * 
     * Assigned patient identifiers
     */
    @OneToMany(targetEntity=TypedIdentifier.class, mappedBy="ownerPerson", fetch=FetchType.EAGER)
    public List<TypedIdentifier> patientIdentifiers;

    /**
     * natural identifiers
     */
    public String surname;

    public String givenNames;
}

TypedIdentifier

@Table(uniqueConstraints = @UniqueConstraint(columnNames={"idType", "idValue"}))
@Entity @IdClass(TypedIdentifier.class)
public class TypedIdentifier implements Serializable
{
    /**
     * internal unique identifier
     */
    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    public Integer id;

    @Id
    @ManyToOne(fetch=FetchType.LAZY)    
    public IdType idType;   // should be a foreign key

    @Id
    public String idValue;

    @ManyToOne(fetch=FetchType.LAZY)
    @JoinColumn
    public Person ownerPerson;
}

IdType

@Entity
public class IdType implements Serializable
{
    @Id
    public String code;
}

IdTypeDescription

@Entity
public class IdTypeDescription implements Serializable
{
    @MapsId
    @JoinColumn(name = "code")
    @OneToOne(cascade = CascadeType.ALL, mappedBy="code")  
    public IdType itype;

    public IdCategory category;

    public String name;
}

如果我需要在SQL中编写它，我就没有问题。但是使用JPA / Hibernate，一件简单的事情就变成了一场噩梦。我从一个错误反弹到另一个错误然后又回来了。

我的问题似乎来自我对IdTypeDescription的itype成员的注释。我尝试了各种方法（基于示例代码和API文档）。

这些注释组合导致我的元模型生成器不为我的静态类生成属性 IdTypeDescription _

@MapsId
@JoinColumn(name = "code")
@OneToOne(cascade = CascadeType.ALL, mappedBy="code")   
public IdType itype;

这些注释组合在hibernate中导致空指针异常，因为它试图创建表：

@Id
@OneToOne(cascade = CascadeType.ALL, mappedBy="code")
public IdType itype;    

或

@Id
@OneToOne(cascade = CascadeType.ALL, mappedBy="code")
@PrimaryKeyJoinColumn
public IdType itype;    

错误：

play.api.http.HttpErrorHandlerExceptions$$anon$1: Execution exception[[ProvisionException: Unable to provision, see the following errors:

1) Error injecting constructor, javax.persistence.PersistenceException: Unable to build entity manager factory
  at play.db.jpa.DefaultJPAApi$JPAApiProvider.<init>(DefaultJPAApi.java:35)
  at play.db.jpa.DefaultJPAApi$JPAApiProvider.class(DefaultJPAApi.java:30)
  while locating play.db.jpa.DefaultJPAApi$JPAApiProvider
  while locating play.db.jpa.JPAApi

1 error]]
    at play.api.http.HttpErrorHandlerExceptions$.throwableToUsefulException(HttpErrorHandler.scala:265) ~[play_2.11-2.4.4.jar:2.4.4]
    at play.api.http.DefaultHttpErrorHandler.onServerError(HttpErrorHandler.scala:191) ~[play_2.11-2.4.4.jar:2.4.4]

    at scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979) [scala-library-2.11.6.jar:na]
    at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107) [scala-library-2.11.6.jar:na]
Caused by: com.google.inject.ProvisionException: Unable to provision, see the following errors:

1) Error injecting constructor, javax.persistence.PersistenceException: Unable to build entity manager factory
  at play.db.jpa.DefaultJPAApi$JPAApiProvider.<init>(DefaultJPAApi.java:35)
  at play.db.jpa.DefaultJPAApi$JPAApiProvider.class(DefaultJPAApi.java:30)
  while locating play.db.jpa.DefaultJPAApi$JPAApiProvider
  while locating play.db.jpa.JPAApi

1 error
    at com.google.inject.internal.InjectorImpl$2.get(InjectorImpl.java:1025) ~[guice-4.0.jar:na]
    at com.google.inject.internal.InjectorImpl.getInstance(InjectorImpl.java:1051) ~[guice-4.0.jar:na]


    at com.google.inject.internal.InjectorImpl$2$1.call(InjectorImpl.java:1016) ~[guice-4.0.jar:na]
    at com.google.inject.internal.InjectorImpl.callInContext(InjectorImpl.java:1092) ~[guice-4.0.jar:na]
    at com.google.inject.internal.InjectorImpl$2.get(InjectorImpl.java:1012) ~[guice-4.0.jar:na]
    ... 38 common frames omitted
Caused by: java.lang.NullPointerException: null
    at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.processFkSecondPassesInOrder(InFlightMetadataCollectorImpl.java:1708) ~[hibernate-core-5.0.5.Final.jar:5.0.5.Final]
    at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.processSecondPasses(InFlightMetadataCollectorImpl.java:1617) ~[hibernate-core-5.0.5.Final.jar:5.0.5.Final]
    at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:278) ~[hibernate-core-5.0.5.Final.jar:5.0.5.Final]
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.metadata(EntityManagerFactoryBuilderImpl.java:770) ~[hibernate-entitymanager-5.0.5.Final.jar:5.0.5.Final]
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:797) ~[hibernate-entitymanager-5.0.5.Final.jar:5.0.5.Final]
    at org.hibernate.jpa.HibernatePersistenceProvider.createEntityManagerFactory(HibernatePersistenceProvider.java:58) ~[hibernate-entitymanager-5.0.5.Final.jar:5.0.5.Final]
    ... 57 common frames omitted