Java Hibernate get parent'；子实体的s id

很多人都发布过类似的问题，但我似乎找不到一个能解决我的情况的

我有一个父实体

Dnar

和一个子实体

WorkLocationSuburb

。

Dnar

具有一对多

工作位置子城市

通常，我会将这种关系定义如下：

孩子

@Entity
@Table(name = "req_work_suburb", schema = SCHEMA)
public class WorkLocationSuburb {

  @Id
  @GeneratedValue(generator = "req_work_suburb_seq")
  @GenericGenerator(strategy="sequence", name="req_work_suburb_seq", parameters={@Parameter(name="sequence", value=SCHEMA+".req_work_suburb_seq")})
  @Column(name = "id", nullable = false)
  private Long id;

  @Column(name="suburb", length=255, nullable=false)
  private String suburb;

  //remainder omitted
}

@Entity
@Table(name = "req_work_suburb", schema = SCHEMA)
public class WorkLocationSuburb {

  @Id
  @GeneratedValue(generator = "req_work_suburb_seq")
  @GenericGenerator(strategy="sequence", name="req_work_suburb_seq", parameters={@Parameter(name="sequence", value=SCHEMA+".req_work_suburb_seq")})
  @Column(name = "id", nullable = false)
  private Long id;

  @Column(name="suburb", length=255, nullable=false)
  private String suburb;

  @ManyToOne
  @JoinColumn(name="dnar_id", nullable=false)
  private Dnar dnar;

  //remainder omitted
}

父项

@Entity
@Table(name = "req_dnar", schema = SCHEMA)
@Inheritance(strategy = JOINED)
@DiscriminatorColumn(name = "form_type", discriminatorType = STRING, length = 64)
public abstract class Dnar {

  @Id
  @GeneratedValue(generator = "req_dnar_seq")
  @GenericGenerator(strategy = "sequence", name = "req_dnar_seq", parameters = { @Parameter(name = "sequence", value = SCHEMA + ".req_dnar_seq") })
  @Column(name = C_DNAR_ID, nullable = false)
  private Long dnarId;

  @Column(name = "original_id")
  private Long originalId;


  @OneToMany(cascade = ALL, fetch = EAGER, orphanRemoval=true)
  @JoinColumn(name = "dnar_id", nullable=false)
  private Set<WorkLocationSuburb> workLocationSuburbs;

  //remainder omitted
}

@Entity
@Table(name = "req_dnar", schema = SCHEMA)
@Inheritance(strategy = JOINED)
@DiscriminatorColumn(name = "form_type", discriminatorType = STRING, length = 64)
public abstract class Dnar {

  @Id
  @GeneratedValue(generator = "req_dnar_seq")
  @GenericGenerator(strategy = "sequence", name = "req_dnar_seq", parameters = { @Parameter(name = "sequence", value = SCHEMA + ".req_dnar_seq") })
  @Column(name = C_DNAR_ID, nullable = false)
  private Long dnarId;

  @Column(name = "original_id")
  private Long originalId;

  @OneToMany(cascade = ALL, fetch = EAGER, orphanRemoval=true, mappedBy="dnar")
  private Set<WorkLocationSuburb> workLocationSuburbs = new LinkedHashSet<WorkLocationSuburb>();


  @PostPersist
  void setChildRefs() {
    for (WorkLocationSuburb suburb : workLocationSuburbs) {
      suburb.setDnar(this);
    }
  }

  //remainder omitted
}

当我执行上述操作时，我得到以下异常：

org.springframework.dao.InvalidDataAccessApiUsageException: Unable to resolve attribute [dnarId] against path; nested exception is java.lang.IllegalArgumentException: Unable to resolve attribute [dnarId] against path
         at org.springframework.orm.jpa.EntityManagerFactoryUtils.convertJpaAccessExceptionIfPossible(EntityManagerFactoryUtils.java:301)
         at org.springframework.orm.jpa.vendor.HibernateJpaDialect.translateExceptionIfPossible(HibernateJpaDialect.java:106)
         at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.translateExceptionIfPossible(AbstractEntityManagerFactoryBean.java:403)
         at org.springframework.dao.support.ChainedPersistenceExceptionTranslator.translateExceptionIfPossible(ChainedPersistenceExceptionTranslator.java:58)
         at org.springframework.dao.support.DataAccessUtils.translateIfNecessary(DataAccessUtils.java:213)
         at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:163)
         at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
         at org.springframework.data.jpa.repository.support.LockModeRepositoryPostProcessor$LockModePopulatingMethodIntercceptor.invoke(LockModeRepositoryPostProcessor.java:91)
         at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
         at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:90)
         at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
         at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202)
         at $Proxy253.findAll(Unknown Source)
         at au.com.wpcorp.sys.dnar.spring.manager.impl.SearchManagerImpl.search(SearchManagerImpl.java:66)
         at au.com.wpcorp.sys.dnar.spring.mvc.controller.search.DnarSearchController.results(DnarSearchController.java:97)
         at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
         at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
         at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
         at java.lang.reflect.Method.invoke(Method.java:597)
         at org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:213)
         at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:126)
         at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:96)
         at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:617)
         at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:578)
         at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80)
         at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:923)
         at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:852)
         at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:882)
         at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:778)
         at javax.servlet.http.HttpServlet.service(HttpServlet.java:668)
         at javax.servlet.http.HttpServlet.service(HttpServlet.java:770)
         at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1550)
         at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:281)
         at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
         at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:655)
         at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:595)
         at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:161)
         at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:331)
         at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:231)
         at com.sun.enterprise.v3.services.impl.ContainerMapper$AdapterCallable.call(ContainerMapper.java:317)
         at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:195)
         at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:860)
         at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:757)
         at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:1056)
         at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:229)
         at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:137)
         at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:104)
         at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:90)
         at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:79)
         at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:54)
         at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:59)
         at com.sun.grizzly.ContextTask.run(ContextTask.java:71)
         at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:532)
         at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:513)
         at java.lang.Thread.run(Thread.java:662)
Caused by: java.lang.IllegalArgumentException: Unable to resolve attribute [dnarId] against path
         at org.hibernate.ejb.criteria.path.AbstractPathImpl.unknownAttribute(AbstractPathImpl.java:118)
         at org.hibernate.ejb.criteria.path.AbstractPathImpl.locateAttribute(AbstractPathImpl.java:223)
         at org.hibernate.ejb.criteria.path.AbstractPathImpl.get(AbstractPathImpl.java:194)
         at au.com.wpcorp.sys.dnar.spring.manager.impl.SearchManagerImpl$3.toPredicate(SearchManagerImpl.java:141)
         at org.springframework.data.jpa.repository.support.SimpleJpaRepository.applySpecificationToCriteria(SimpleJpaRepository.java:480)
         at org.springframework.data.jpa.repository.support.SimpleJpaRepository.getQuery(SimpleJpaRepository.java:436)
         at org.springframework.data.jpa.repository.support.SimpleJpaRepository.getQuery(SimpleJpaRepository.java:421)
         at org.springframework.data.jpa.repository.support.SimpleJpaRepository.findAll(SimpleJpaRepository.java:303)
         at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
         at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
         at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
         at java.lang.reflect.Method.invoke(Method.java:597)
         at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.executeMethodOn(RepositoryFactorySupport.java:334)
         at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.invoke(RepositoryFactorySupport.java:319)
         at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
         at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:110)
         at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
         at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:155)
         ... 49 more

它似乎失败了，因为Hibernate在

WorkLocationSuburb

上找不到名为

DNAND

的属性。我的问题是，如何将这些信息添加到

WorkLocationSuburb

，而不让Hibernate抱怨其他问题？似乎我需要一些代码，如：

@Entity
@Table(name = "req_work_suburb", schema = SCHEMA)
public class WorkLocationSuburb {

  @Id
  @GeneratedValue(generator = "req_work_suburb_seq")
  @GenericGenerator(strategy="sequence", name="req_work_suburb_seq", parameters={@Parameter(name="sequence", value=SCHEMA+".req_work_suburb_seq")})
  @Column(name = "id", nullable = false)
  private Long id;

  @Column(name="suburb", length=255, nullable=false)
  private String suburb;

  @Column(name="dnar_id", nullable=false)  // column definition added here
  private Long dnarId;

  //remainder omitted
}

有人知道我怎样才能让上面的附加专栏发挥作用吗？此列必须自动填充父级的

dnand

谢谢， 穆尔

---

更新了JB Nizet的建议

我的代码现在是这样的：

孩子

@Entity
@Table(name = "req_work_suburb", schema = SCHEMA)
public class WorkLocationSuburb {

  @Id
  @GeneratedValue(generator = "req_work_suburb_seq")
  @GenericGenerator(strategy="sequence", name="req_work_suburb_seq", parameters={@Parameter(name="sequence", value=SCHEMA+".req_work_suburb_seq")})
  @Column(name = "id", nullable = false)
  private Long id;

  @Column(name="suburb", length=255, nullable=false)
  private String suburb;

  //remainder omitted
}

@Entity
@Table(name = "req_work_suburb", schema = SCHEMA)
public class WorkLocationSuburb {

  @Id
  @GeneratedValue(generator = "req_work_suburb_seq")
  @GenericGenerator(strategy="sequence", name="req_work_suburb_seq", parameters={@Parameter(name="sequence", value=SCHEMA+".req_work_suburb_seq")})
  @Column(name = "id", nullable = false)
  private Long id;

  @Column(name="suburb", length=255, nullable=false)
  private String suburb;

  @ManyToOne
  @JoinColumn(name="dnar_id", nullable=false)
  private Dnar dnar;

  //remainder omitted
}

父项

@Entity
@Table(name = "req_dnar", schema = SCHEMA)
@Inheritance(strategy = JOINED)
@DiscriminatorColumn(name = "form_type", discriminatorType = STRING, length = 64)
public abstract class Dnar {

  @Id
  @GeneratedValue(generator = "req_dnar_seq")
  @GenericGenerator(strategy = "sequence", name = "req_dnar_seq", parameters = { @Parameter(name = "sequence", value = SCHEMA + ".req_dnar_seq") })
  @Column(name = C_DNAR_ID, nullable = false)
  private Long dnarId;

  @Column(name = "original_id")
  private Long originalId;


  @OneToMany(cascade = ALL, fetch = EAGER, orphanRemoval=true)
  @JoinColumn(name = "dnar_id", nullable=false)
  private Set<WorkLocationSuburb> workLocationSuburbs;

  //remainder omitted
}

@Entity
@Table(name = "req_dnar", schema = SCHEMA)
@Inheritance(strategy = JOINED)
@DiscriminatorColumn(name = "form_type", discriminatorType = STRING, length = 64)
public abstract class Dnar {

  @Id
  @GeneratedValue(generator = "req_dnar_seq")
  @GenericGenerator(strategy = "sequence", name = "req_dnar_seq", parameters = { @Parameter(name = "sequence", value = SCHEMA + ".req_dnar_seq") })
  @Column(name = C_DNAR_ID, nullable = false)
  private Long dnarId;

  @Column(name = "original_id")
  private Long originalId;

  @OneToMany(cascade = ALL, fetch = EAGER, orphanRemoval=true, mappedBy="dnar")
  private Set<WorkLocationSuburb> workLocationSuburbs = new LinkedHashSet<WorkLocationSuburb>();


  @PostPersist
  void setChildRefs() {
    for (WorkLocationSuburb suburb : workLocationSuburbs) {
      suburb.setDnar(this);
    }
  }

  //remainder omitted
}

@实体
@表（name=“req_dnar”，schema=schema）
@继承（策略=加入）
@鉴别器列（name=“form\u type”，鉴别器类型=字符串，长度=64）
公共抽象类Dnar{
@身份证
@GeneratedValue（generator=“需求数据顺序”）
@GenericGenerator（strategy=“sequence”，name=“req_dnar_seq”，parameters={@Parameter（name=“sequence”，value=SCHEMA+”.req_dnar_seq”）}）
@列（name=C\u DNAR\u ID，null=false）
私人长途电话；
@列（名称=“原始id”）
私人长源代码；
@OneToMany（cascade=ALL，fetch=EAGER，orphaneremovation=true，mappedBy=“dnar”）
private Set workLocationSuburbs=new LinkedHashSet（）；
@后复印机
void setChildRefs（）{
对于（WorkLocationSuburb郊区：workLocationSuburbs）{
郊区。塞德纳尔（本）；
}
}
//省略的余数
}

当我尝试保存附加了

WorkLocationSuburb

的

Dnar

时，我会看到以下事件顺序：

将

Dnar

插入数据库

调用

@PostConstuct

，并且

WorkLocationSuburb

获取对父

Dnar

的引用。父级

Dnar

已正确分配ID

尝试插入子

WorkLocationSuburb

，但导致以下异常：org.hibernate.exception.ConstraintViolationException:ORA-01400:无法将NULL插入（“DNAR”。“请求工作郊区”。“DNAR\U ID”）`

---

我还在错误地做什么？：）

您只需将关联设置为双向：

public class WorkLocationSuburb {
    @ManyToOne
    @JoinColumn
    private Dnar parentDnar;
    // ...
}

public class Dnar {
    @OneToMany(mappedBy = "parentDnar", ...)
    private Set<WorkLocationSuburb> suburbs;
    // ...
}

类似地，如果从dnar中删除郊区，则应将郊区的parentDnar设置为null

---

关于查询，现在可以在查询中使用

parentDnar

字段。记住，JPA查询总是在实体及其持久字段/属性上工作。从不在表及其列上使用。我尝试了您的建议，但Hibernate不知道如何在子实体上填充外键列。请问我错过了什么？哦，我在上面的问题中添加了我尝试过的代码。试着不要使用PostPersist钩子来设置父ID。我很确定在这种回调方法中不应该修改实体。只需将其封装在实体或服务方法中即可。谢谢，伙计，这就解决了它！