Java：休眠@OneToOne 映射
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Java: Hibernate @OneToOne mapping
提问by Shaun Scovil
I'm trying to get Hibernate @OneToOne annotations working and not having much success here...
我正在尝试让 Hibernate @OneToOne 注释正常工作，但在这里没有取得太大的成功......
Let's say I've got a table called statusthat looks like this:
假设我有一个名为的表status，如下所示：
+------------------------------------------------+
| status |
+------------------------------------------------+
| id | frn_user_id | frn_content_id | status |
+----+-------------+----------------+------------+
| 1 | 111 | 0 | "active" |
+----+-------------+----------------+------------+
| 2 | 0 | 222 | "inactive" |
+----+-------------+----------------+------------+
And I've got an entity for Userthat looks like this:
我有一个User看起来像这样的实体：
@Entity
@Table(name = "user")
public class User {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "id", nullable = false)
private Integer id;
@OneToOne(cascade = CascadeType.ALL, fetch = FetchType.EAGER, mappedBy = "userId")
private Status status;
// getters and setters
}
And a similar one for Content, and another entity for Statusthat looks like this:
和一个类似的 for Content，另一个实体Status看起来像这样：
@Entity
@Table(name = "status")
public class Status {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "id", nullable = false)
private Integer id;
@Column(name = "frn_user_id")
private Integer userId;
@Column(name = "frn_content_id")
private Integer contentId;
@Column(name = "status")
private String status;
// getters and setters
}
When I perform a read on User, I expect that User.getStatus()will return a Statusobject with id=1. Instead, I get an AnnotationException: "Referenced property not a (One|Many)ToOne: Status.userId in mappedBy User.status"
当我执行读取时User，我希望它User.getStatus()会返回一个Status带有id=1. 相反，我得到一个 AnnotationException：“引用的属性不是（一个|多）ToOne：映射的 User.status 中的 Status.userId”
I've poured through docs, tutorials and examples here on SO, but everything I've tried so far has failed.
我已经在 SO 上倾注了文档、教程和示例，但到目前为止我尝试过的一切都失败了。
Also worth noting: This should support a one-to-zero-or-one relationship, as some userand contentrecords will not have a reference in the statustable.
另外值得一提的是：这应该支持一到零或一的关系，因为一些user和content记录不会有在参考status表。
Any help would be greatly appreciated!
任何帮助将不胜感激！
采纳答案by JB Nizet
Your Status entity must not have properties userIdand contentIdof type Integer, mapped with @Column. It must have properties userand contentof type User and Content, mapped with @OneToOne:
您的 Status 实体不得具有Integer 类型的属性，userId并contentId使用@Column. 它必须具有的属性user和content类型的用户和内容，与映射的@OneToOne：
public class User {
@OneToOne(mappedBy = "user")
private Status status;
// ...
}
public class Status {
@OneToOne
@JoinColumn(name = "frn_user_id")
private User user;
// ...
}
A user has one status. A status has one user.
一个用户有一个状态。一个状态有一个用户。
回答by Abhishek
use this way. Add below field in Customer entity.
使用这种方式。在客户实体中添加以下字段。
@OneToOne(fetch = FetchType.LAZY, cascade = CascadeType.ALL, mappedBy = "customer")
private Status status;
and don't add getter and setter for status field in Customer entity. And add below code to Status Entity.
并且不要为 Customer 实体中的状态字段添加 getter 和 setter。并将以下代码添加到状态实体。
@OneToOne(fetch = FetchType.LAZY, optional = false)
@JoinColumn(name = "customer_id", nullable = false)
private Customer customer;
Here add the getter and setter for customer field in Status Entity class. You can see one working example here.
这里为状态实体类中的客户字段添加 getter 和 setter。您可以在此处查看一个工作示例。
