Question

我有一个电话对象和一个电话历史记录对象。我希望能够检索电话历史记录对象，然后获取其父级（电话），但出于某种原因，当我尝试这样做然后坚持孩子时，我得到一个例外，说明没有填充phone_id 。不知道如何解决这个问题，虽然我怀疑它与我的映射注释有关。

以下是我的实体课程。我已经尝试更改注释以匹配双向关系部分中的建议：http://docs.jboss.org/hibernate/annotations/3.5/reference/en/html/entity.html#entity-mapping-association但这似乎没有做到这一点。我是JPA的新手，所以对于经验丰富的人来说这可能很简单，但我很难过。 TIA。

电话实体：

package com.blah.model;

import java.util.ArrayList;
import java.util.Calendar;
import java.util.List;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.OneToMany;
import javax.persistence.Table;
import javax.persistence.Temporal;
import javax.persistence.TemporalType;

@Entity
@Table(name = "phones")
public class EPhone implements BaseModel {

    private static final long serialVersionUID = 3497994786207995664L;

    @Id
    @GeneratedValue
    @Column(name = "id")
    private Long id;

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "account_id",
            nullable = false)
    private EAccount account;

    @Temporal(TemporalType.TIMESTAMP)
    private Calendar created;

    @Column(name = "value",
        nullable = false)
        private Long value;

    @OneToMany(fetch = FetchType.LAZY,
            mappedBy = "phone",
            cascade = CascadeType.ALL)
    private final List<EPhoneHistory> history;

    public EPhone() {
        this(Calendar.getInstance());
    }

    public EPhone(final Calendar createdDate) {
        setCreated(createdDate);
        history = new ArrayList<EPhoneHistory>();
    }

    public void add(EPhoneHistory phoneHistoryItem) {
        history.add(phoneHistoryItem);
    }

    public EAccount getAccount() {
        return account;
    }

    public Calendar getCreated() {
        return created;
    }

    @OneToMany(fetch = FetchType.LAZY,
            mappedBy = "phone",
            cascade = CascadeType.ALL)
    public List<EPhoneHistory> getHistory() {
        return history;
    }

    public Long getId() {
        return id;
    }

    public Long getValue() {
        return value;
    }

    public void setAccount(EAccount account) {
        this.account = account;
    }

    public void setCreated(Calendar created) {
        this.created = created;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public void setValue(Long value) {
        this.value = value;
    }

}

电话历史实体：

package com.blah.model;

import java.util.Calendar;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.EnumType;
import javax.persistence.Enumerated;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.Table;
import javax.persistence.Temporal;
import javax.persistence.TemporalType;

@Entity
@Table(name = "phone_history")
public class EPhoneHistory implements BaseModel {

    private static final long serialVersionUID = 4591314258588732076L;

    @Id
    @GeneratedValue
    @Column(name = "id")
    private Long Id;

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "phone_id",
            nullable = false)
    private EPhone phone;

    @Temporal(TemporalType.TIMESTAMP)
    private Calendar created;

    @Enumerated(EnumType.ORDINAL)
    @Column(name = "type_id")
    private PhoneHistoryType type;

    public Calendar getCreated() {
        return created;
    }

    public Long getId() {
        return Id;
    }

    public EPhone getPhone() {
        return phone;
    }

    public PhoneHistoryType getType() {
        return type;
    }

    public void setCreated(Calendar created) {
        this.created = created;
    }

    public void setId(Long id) {
        Id = id;
    }

    public void setPhone(EPhone phone) {
        this.phone = phone;
    }

    public void setType(PhoneHistoryType type) {
        this.type = type;
    }

}

更新澄清（这是一项失败的测试）：

package com.blah.model.repository;

import org.junit.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.transaction.annotation.Transactional;

import com.blah.AbstractBaseDbTestCase;
import com.blah.model.EPhoneHistory;
import com.blah.model.PhoneHistoryType;

public class PhoneHistoryRepositoryTest extends AbstractBaseDbTestCase {

    @Autowired
    PhoneHistoryRepository phoneHistoryRepo;

    @Test
    @Transactional
    public void testCreateAndSavePhoneHistory() {

        EPhoneHistory existingPhoneHistory = phoneHistoryRepo.find(1L);

        EPhoneHistory newPhoneHistory = new EPhoneHistory();
        newPhoneHistory.setType(PhoneHistoryType.VOICE);

        // I assume this is where I would
        // set the phone, but I don't have it.
        // existingPhoneHistory.setPhone(phone);

        // This is what I'm having trouble with. getPhone() doesn't populate the
        // phone field with the parent phone object.
        existingPhoneHistory.getPhone().add(newPhoneHistory);

        phoneHistoryRepo.persist(existingPhoneHistory);
        phoneHistoryRepo.flush();
    }
}

失败堆栈跟踪：

org.springframework.dao.DataIntegrityViolationException: NULL not allowed for column "PHONE_ID"; SQL statement:
insert into phone_history (id, created, phone_id, type_id) values (null, ?, ?, ?) [23502-168]; SQL [n/a]; constraint [null]; nested exception is org.hibernate.exception.ConstraintViolationException: NULL not allowed for column "PHONE_ID"; SQL statement:
insert into phone_history (id, created, phone_id, type_id) values (null, ?, ?, ?) [23502-168]
    at org.springframework.orm.hibernate3.SessionFactoryUtils.convertHibernateAccessException(SessionFactoryUtils.java:643)
    at org.springframework.orm.jpa.vendor.HibernateJpaDialect.translateExceptionIfPossible(HibernateJpaDialect.java:104)
    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.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:110)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
    at org.springframework.aop.framework.Cglib2AopProxy$DynamicAdvisedInterceptor.intercept(Cglib2AopProxy.java:622)
    at com.blah.model.repository.PhoneHistoryRepository$$EnhancerByCGLIB$$4f90cdde.flush(<generated>)
    at com.blah.model.repository.PhoneHistoryRepositoryTest.testCreateAndSavePhoneHistory(PhoneHistoryRepositoryTest.java:29)
    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.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:45)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:42)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
    at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:74)
    at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:30)
    at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:83)
    at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:72)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:231)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:47)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:231)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:60)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:229)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:50)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:222)
    at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
    at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:71)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:300)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:174)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
Caused by: org.hibernate.exception.ConstraintViolationException: NULL not allowed for column "PHONE_ID"; SQL statement:
insert into phone_history (id, created, phone_id, type_id) values (null, ?, ?, ?) [23502-168]
    at org.hibernate.exception.internal.SQLStateConversionDelegate.convert(SQLStateConversionDelegate.java:128)
    at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:49)
    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:125)
    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:110)
    at org.hibernate.engine.jdbc.internal.proxy.AbstractStatementProxyHandler.continueInvocation(AbstractStatementProxyHandler.java:129)
    at org.hibernate.engine.jdbc.internal.proxy.AbstractProxyHandler.invoke(AbstractProxyHandler.java:81)
    at $Proxy37.executeUpdate(Unknown Source)
    at org.hibernate.id.IdentityGenerator$GetGeneratedKeysDelegate.executeAndExtract(IdentityGenerator.java:96)
    at org.hibernate.id.insert.AbstractReturningDelegate.performInsert(AbstractReturningDelegate.java:58)
    at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2870)
    at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:3381)
    at org.hibernate.action.internal.EntityIdentityInsertAction.execute(EntityIdentityInsertAction.java:81)
    at org.hibernate.engine.spi.ActionQueue.execute(ActionQueue.java:362)
    at org.hibernate.engine.spi.ActionQueue.addResolvedEntityInsertAction(ActionQueue.java:203)
    at org.hibernate.engine.spi.ActionQueue.addInsertAction(ActionQueue.java:183)
    at org.hibernate.engine.spi.ActionQueue.addAction(ActionQueue.java:167)
    at org.hibernate.event.internal.AbstractSaveEventListener.addInsertAction(AbstractSaveEventListener.java:320)
    at org.hibernate.event.internal.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:287)
    at org.hibernate.event.internal.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:193)
    at org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:126)
    at org.hibernate.ejb.event.EJB3PersistEventListener.saveWithGeneratedId(EJB3PersistEventListener.java:78)
    at org.hibernate.event.internal.DefaultPersistEventListener.entityIsTransient(DefaultPersistEventListener.java:208)
    at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:151)
    at org.hibernate.internal.SessionImpl.firePersistOnFlush(SessionImpl.java:870)
    at org.hibernate.internal.SessionImpl.persistOnFlush(SessionImpl.java:863)
    at org.hibernate.engine.spi.CascadingAction$8.cascade(CascadingAction.java:346)
    at org.hibernate.engine.internal.Cascade.cascadeToOne(Cascade.java:380)
    at org.hibernate.engine.internal.Cascade.cascadeAssociation(Cascade.java:323)
    at org.hibernate.engine.internal.Cascade.cascadeProperty(Cascade.java:208)
    at org.hibernate.engine.internal.Cascade.cascadeCollectionElements(Cascade.java:409)
    at org.hibernate.engine.internal.Cascade.cascadeCollection(Cascade.java:350)
    at org.hibernate.engine.internal.Cascade.cascadeAssociation(Cascade.java:326)
    at org.hibernate.engine.internal.Cascade.cascadeProperty(Cascade.java:208)
    at org.hibernate.engine.internal.Cascade.cascade(Cascade.java:165)
    at org.hibernate.event.internal.AbstractFlushingEventListener.cascadeOnFlush(AbstractFlushingEventListener.java:160)
    at org.hibernate.event.internal.AbstractFlushingEventListener.prepareEntityFlushes(AbstractFlushingEventListener.java:151)
    at org.hibernate.event.internal.AbstractFlushingEventListener.flushEverythingToExecutions(AbstractFlushingEventListener.java:88)
    at org.hibernate.event.internal.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:51)
    at org.hibernate.internal.SessionImpl.flush(SessionImpl.java:1214)
    at org.hibernate.ejb.AbstractEntityManagerImpl.flush(AbstractEntityManagerImpl.java:986)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:240)
    at $Proxy32.flush(Unknown Source)
    at com.blah.model.repository.AbstractRepository.flush(AbstractRepository.java:41)
    at com.blah.model.repository.AbstractRepository$$FastClassByCGLIB$$1ba8d45c.invoke(<generated>)
    at net.sf.cglib.proxy.MethodProxy.invoke(MethodProxy.java:149)
    at org.springframework.aop.framework.Cglib2AopProxy$CglibMethodInvocation.invokeJoinpoint(Cglib2AopProxy.java:689)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
    at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:155)
    ... 36 more
Caused by: org.h2.jdbc.JdbcSQLException: NULL not allowed for column "PHONE_ID"; SQL statement:
insert into phone_history (id, created, phone_id, type_id) values (null, ?, ?, ?) [23502-168]
    at org.h2.message.DbException.getJdbcSQLException(DbException.java:329)
    at org.h2.message.DbException.get(DbException.java:169)
    at org.h2.message.DbException.get(DbException.java:146)
    at org.h2.table.Column.validateConvertUpdateSequence(Column.java:293)
    at org.h2.table.Table.validateConvertUpdateSequence(Table.java:689)
    at org.h2.command.dml.Insert.insertRows(Insert.java:120)
    at org.h2.command.dml.Insert.update(Insert.java:84)
    at org.h2.command.CommandContainer.update(CommandContainer.java:75)
    at org.h2.command.Command.executeUpdate(Command.java:230)
    at org.h2.jdbc.JdbcPreparedStatement.executeUpdateInternal(JdbcPreparedStatement.java:156)
    at org.h2.jdbc.JdbcPreparedStatement.executeUpdate(JdbcPreparedStatement.java:142)
    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.hibernate.engine.jdbc.internal.proxy.AbstractStatementProxyHandler.continueInvocation(AbstractStatementProxyHandler.java:122)
    ... 83 more

Answer 1

由于你已经建立了联接lazy，我怀疑你的子对象phone中没有填充父对象phoneHistory。请验证（通过phoneHistory调试/打印电话对象值）。如果是这样，请先保存phone对象，然后再保存phoneHistory。

在addPhoneHistory对象中添加方法Phone，如下所示：

      public void addPhoneHistory(PhoneHistory phoneHistory){
         phoneHistory.setPhone(this); //This is importtant as its sets the parent
         if(this.phoneHistories == null){
            this.phoneHistories = new ArrayList<PhoneHistory>();
         } 
         this.phoneHistories.add(phoneHistory); 
      }

在代码中添加一行，在PhoneHistory对象中添加Phone对象以使用上述方法。

    existingPhoneHistory.getPhone().addPhoneHistory(newPhoneHistory);

同样最好保存'Phone in place of existingPhoneHistory`，如下所示：

   Phone phone = existingPhoneHistory.getPhone();
   phone.addPhoneHistory(newPhoneHistory);
   entityManager.save(phone);//use your PhoneRepo, if there to persist

希望这有帮助。

Answer 2

签入填充phone_id变量的SQL查询（或您使用的其他一些数据采集系统）已用于获取列字段。其次，检查那些字段是否被任何应该创建phone_id数据的系统填充（例如，其他servlet管理并将信息发送到sql表中）。

Answer 3

应该很容易修复。

LAZY装载不是问题。
所有测试调用都在同一个Spring测试事务中运行。因此，当您通过.getXXX（）调用遍历关系以获取必要的数据时，JPA提供程序将自动加载所有加载LAZY的关系。
测试代码中的错误。在子对象newPhoneHistory中，您尚未设置phone对象，该对象提供必需的列phoneId。致电之前或之后：
```
existingPhoneHistory.getPhone().add(newPhoneHistory);
```
只需添加：
```
newPhoneHistory.setPhone(existingPhoneHistory.getPhone());
```

您需要在双向关系的两侧手动设置关系数据。从JPA 2规范：

管理实体之间的双向关系将根据关系所属方持有的引用来保留。开发人员有责任保持内存引用保持在拥有方，而保持在反方的引用在更改时保持一致。在单向一对一和一对多关系的情况下，开发人员有责任确保（原文如此）遵守关系的语义。 [29]

特别重要的是要确保对关系的反面进行更改会在所属方面产生适当的更新，以确保更改在与数据库同步时不会丢失。

： - ）

使用JPA让孩子从父母那里获得

3 个答案: