使用连接实体删除JPA/Hibernate孤儿

Question

下面是场景：

@Entity
@Table(name = "Item")
public class Item implements java.io.Serializable {

  private Integer itemId; //Auto Genenerated Unique ID
  private String item; //Item description
  private Set<ItemContainer> itemContainers = new HashSet<ItemContainer>(0); //Set of ItemContainers

  @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "item", orphanRemoval = true)
  public Set<ItemContainer> getItemContainers() {
    return this.itemContainers;
  }
}

@Entity
@Table(name = "ItemContainer")
public class ItemContainer implements java.io.Serializable {

  private Integer itemContainerId; //Auto Genenerated Unique ID
  private Item item; //Item link
  private Container container; //Container link

  @ManyToOne(fetch = FetchType.EAGER)
  @JoinColumn(name = "itemId")
  public Item getItem() {
    return this.item;
  }

  @ManyToOne(fetch = FetchType.EAGER)
  @JoinColumn(name = "containerId")
  public Container getContainer() {
    return this.container;
  }
}

@Entity
@Table(name = "Container")
public class Container implements java.io.Serializable {

  private Integer containerId; //Auto Genenerated Unique ID
  private String container; //description
  private Set<ItemContainer> itemContainers = new HashSet<ItemContainer>(0);

  @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "container", orphanRemoval = true)
  public Set<ItemContainer> getItemContainers() {
    return this.itemContainers;
  }
}

容器和项都可以存在排他性。ItemContainer只能包含对现有项和容器的引用

我想要做的是能够删除一个项目，并删除它对应的ItemContainer行（使用孤儿删除）。任何容器都应该仍然存在。

@Override
public void delete(Item item) {
  EntityManager em = getEntityManager();
  em.remove(em.contains(item) ? item: em.merge(item));
}

编辑1：正如JB所要求的：下面是正在使用的相关代码。

请求来自一个jsp

/deleteItem?itemId=${item.itemId}

值得一提的是，我试图在我的jUnit测试中做同样的事情（如果需要，我可以发布测试代码和任何相关的类），但是我没有收到错误（它通过时没有抛出FK约束错误，但是ItemContainer表仍然包含对已删除项的引用）。

@Controller
public class ItemController {

  @Autowired
  private ItemsService itemsService;

  @RequestMapping(value = "/deleteItem")
  public String deleteItem(@RequestParam() int itemId) {

    itemsService.delete(itemId);

    return "redirect:systemSettings/items";
  }
}

@Service("itemsService")
public class ItemsService {

  @Autowired
  private ItemsDAO itemsDao;

  public void delete(int itemId) {

    itemsDao.delete(itemsDao.getItem(itemId));
  }
}

@Repository
@Transactional
@Component("itemsDao")
public class ItemsDAOImpl implements ItemsDAO {

  @PersistenceContext
  private EntityManager entityManager;

  @Override
  public EntityManager getEntityManager() {
    return entityManager;
  }

  @Override
  public void setEntityManager(EntityManager entityManager) {
    this.entityManager = entityManager;
  }

  @Override
  public Item getItem(int itemId) {
    String queryString = "SELECT i FROM Item i "
        + "LEFT JOIN FETCH i.itemMachines "
        + "WHERE i.itemId=:itemId";
    Query query = getEntityManager().createQuery(queryString);
    query.setParameter("itemId", itemId);

    Item item = (Item) query.getSingleResult();
    System.out.println(item.getItemMachines().size());

    return item;
  }

  @Override
  public void delete(Item item) {
    EntityManager em = getEntityManager();
    em.remove(em.contains(item) ? item : em.merge(item));
  } 
}

org.springframework.dao.DataIntegrityViolationException: could not execute statement; SQL [n/a]; constraint [null]; nested exception is org.hibernate.exception.ConstraintViolationException: could not execute statement
    at org.springframework.orm.jpa.vendor.HibernateJpaDialect.convertHibernateAccessException(HibernateJpaDialect.java:189)
    at org.springframework.orm.jpa.vendor.HibernateJpaDialect.translateExceptionIfPossible(HibernateJpaDialect.java:155)
    at org.springframework.orm.jpa.JpaTransactionManager.doCommit(JpaTransactionManager.java:519)
    at org.springframework.transaction.support.AbstractPlatformTransactionManager.processCommit(AbstractPlatformTransactionManager.java:757)
    at org.springframework.transaction.support.AbstractPlatformTransactionManager.commit(AbstractPlatformTransactionManager.java:726)
    at org.springframework.transaction.interceptor.TransactionAspectSupport.commitTransactionAfterReturning(TransactionAspectSupport.java:478)
    at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:272)
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:95)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:207)
    at com.sun.proxy.$Proxy29.delete(Unknown Source)
    at com.home.myproject.service.ItemsService.delete(ItemsService.java:45)
    at com.home.myproject.service.ItemsService$$FastClassBySpringCGLIB$$788e7765.invoke(<generated>)
    at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204)
    at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:640)
    at com.home.myproject.service.ItemsService$$EnhancerBySpringCGLIB$$296a7299.delete(<generated>)
    at com.home.myproject.controllers.ItemController.deleteItem(ItemController.java:121)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:483)
    at org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:215)
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:132)
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:104)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:749)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:689)
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:83)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:938)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:870)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:961)
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:852)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:620)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:837)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1040)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:607)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:315)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:744)
Caused by: org.hibernate.exception.ConstraintViolationException: could not execute statement
    at org.hibernate.exception.internal.SQLStateConversionDelegate.convert(SQLStateConversionDelegate.java:129)
    at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:49)
    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:126)
    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:112)
    at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate(ResultSetReturnImpl.java:211)
    at org.hibernate.engine.jdbc.batch.internal.NonBatchingBatch.addToBatch(NonBatchingBatch.java:62)
    at org.hibernate.persister.entity.AbstractEntityPersister.delete(AbstractEntityPersister.java:3400)
    at org.hibernate.persister.entity.AbstractEntityPersister.delete(AbstractEntityPersister.java:3630)
    at org.hibernate.action.internal.EntityDeleteAction.execute(EntityDeleteAction.java:114)
    at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:463)
    at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:349)
    at org.hibernate.event.internal.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:350)
    at org.hibernate.event.internal.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:56)
    at org.hibernate.internal.SessionImpl.flush(SessionImpl.java:1222)
    at org.hibernate.internal.SessionImpl.managedFlush(SessionImpl.java:425)
    at org.hibernate.engine.transaction.internal.jdbc.JdbcTransaction.beforeTransactionCommit(JdbcTransaction.java:101)
    at org.hibernate.engine.transaction.spi.AbstractTransactionImpl.commit(AbstractTransactionImpl.java:177)
    at org.hibernate.jpa.internal.TransactionImpl.commit(TransactionImpl.java:77)
    at org.springframework.orm.jpa.JpaTransactionManager.doCommit(JpaTransactionManager.java:515)
    ... 50 more
Caused by: com.microsoft.sqlserver.jdbc.SQLServerException: The DELETE statement conflicted with the REFERENCE constraint "FK_ItemContainer_Item". The conflict occurred in database "MyDatabase2", table "dbo.ItemContainer", column 'itemId'.
    at com.microsoft.sqlserver.jdbc.SQLServerException.makeFromDatabaseError(Unknown Source)
    at com.microsoft.sqlserver.jdbc.SQLServerStatement.getNextResult(Unknown Source)
    at com.microsoft.sqlserver.jdbc.SQLServerPreparedStatement.doExecutePreparedStatement(Unknown Source)
    at com.microsoft.sqlserver.jdbc.SQLServerPreparedStatement$PrepStmtExecCmd.doExecute(Unknown Source)
    at com.microsoft.sqlserver.jdbc.TDSCommand.execute(Unknown Source)
    at com.microsoft.sqlserver.jdbc.SQLServerConnection.executeCommand(Unknown Source)
    at com.microsoft.sqlserver.jdbc.SQLServerStatement.executeCommand(Unknown Source)
    at com.microsoft.sqlserver.jdbc.SQLServerStatement.executeStatement(Unknown Source)
    at com.microsoft.sqlserver.jdbc.SQLServerPreparedStatement.executeUpdate(Unknown Source)
    at org.apache.tomcat.dbcp.dbcp.DelegatingPreparedStatement.executeUpdate(DelegatingPreparedStatement.java:105)
    at org.apache.tomcat.dbcp.dbcp.DelegatingPreparedStatement.executeUpdate(DelegatingPreparedStatement.java:105)
    at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate(ResultSetReturnImpl.java:208)
    ... 64 more

发现这个问题JPA级联移除孤儿-James的答案证实了JB所说的，但仍然不知道为什么它不能工作：（

Answer 1

第一个想法（结果是错误的，请检查编辑以获得解决方案）

好了，我已经找到这个问题的答案了。

首先让我介绍一下解决方案的上下文（和问题，因为我仍然有点困惑）。

通过MS SQLServer Management Studio将两个外键设置为级联删除可以解决此问题。我现在可以删除一个项目，并让它正确地删除链接它们的ItemContainer记录。

编辑1:
--------------------------------------------------

既然有了新的html" target="_blank">消息，我想我会更新这个。

这是我的职能

public void delete(int itemId) {

  itemsDao.delete(itemsDao.getItem(itemId));
}

注意:
1。来自DAO
2的服务请求项。DAO将项返回给服务
3。服务将项目传递给DAO

将@transaction添加到此方法中（或将其完全从DAO中移除并将其放入服务类）可以修复该问题。