我想您可能忘记了将逻辑 Package 在@ transmitting块中

@Transactional
PaperSetting paperSettingInDb = paperSettingRepository.findOne(1);
PaperSubjectType paperSubjectType = new PaperSubjectType();
paperSubjectType.setSubjectCode("91");
paperSubjectType.setPaperSetting(paperSettingInDb);

paperSubjectTypeRepository.save(paperSubjectType);

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如果没有这个，crudRepository.findOne()将打开它自己的短暂事务，所以当你得到findOne（）的返回时，实体已经被分离了，因此出现错误

我tried it的Hibernate 5.2和它的工作就像一个魅力。
假设你有这些实体：

@Entity(name = "Person")
public static class Person  {

    @Id
    @GeneratedValue
    private Long id;

    @NaturalId
    private String registrationNumber;

    public Person() {}

    public Person(String registrationNumber) {
        this.registrationNumber = registrationNumber;
    }

    public Long getId() {
        return id;
    }

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

    public String getRegistrationNumber() {
        return registrationNumber;
    }
}

@Entity(name = "PersonDetails")
public static class PersonDetails  {

    @Id
    private Long id;

    private String nickName;

    @OneToOne
    @MapsId
    private Person person;

    public String getNickName() {
        return nickName;
    }

    public void setNickName(String nickName) {
        this.nickName = nickName;
    }

    public Person getPerson() {
        return person;
    }

    public void setPerson(Person person) {
        this.person = person;
    }
}

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这种数据访问逻辑：

Person _person = doInJPA( this::entityManagerFactory, entityManager -> {
    Person person = new Person( "ABC-123" );
    entityManager.persist( person );

    return person;
} );

doInJPA( this::entityManagerFactory, entityManager -> {
    Person person = entityManager.find( Person.class, _person.getId() );

    PersonDetails personDetails = new PersonDetails();
    personDetails.setNickName( "John Doe" );
    personDetails.setPerson( person );

    entityManager.persist( personDetails );
} );

型
在Hibernate ORM中测试通过得很好。
也许是5.0中的一个bug被修复了，所以你最好升级。

**1）**增加级联选项：

@OneToOne(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
@MapsId
private PaperSetting paperSetting;

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**2）**有了它，您可以在重新创建两个实体时仅保存PaperSubjectType：

PaperSetting paperSetting = new PaperSetting();
paperSetting.setxx;
PaperSubjectType paperSubjectType = new PaperSubjectType();
paperSubjectType.setPaperSetting(paperSettingInDbNew);
paperSubjectTypeRepository.save(paperSubjectType);

型

原因是因为实体处于分离状态。这是如何发生的？您传递的实体不处于持久化状态-这意味着它与持久化上下文无关。因此解决方案之一是：

PaperSetting paperSetting = new PaperSetting();
paperSetting.setxx;
PaperSubjectType paperSubjectType = new PaperSubjectType();

// we create PaperSetting entity and we pass it before saving it,
// as it will bedetached from the persistent context as soon as we save it
paperSubjectType.setPaperSetting(paperSetting);

paperSubjectTypeRepository.save(paperSubjectType);

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