OneToOne mappedBy注释的JPA(Hibernate)问题

Question

在设置oneToOne关系时，我有两个表。Bill和BillSimpleEntry。（每张票据有一个BillSimpleEntry

这是他们的结构

CREATE TABLE `bill` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT,
  ..
  ..
  PRIMARY KEY (`id`),
  UNIQUE KEY `id_UNIQUE` (`id`),
  KEY `fk_bill_groups1_idx` (`groupId`),
  KEY `fk_bill_user1_idx` (`billPayerId`),
  CONSTRAINT `fk_b...` FOREIGN KEY (`groupId`) REFERENCES `groups` (`id`) ON D     ELETE  NO ACTION ON UPDATE NO ACTION,
  CONSTRAINT `fk_b...` FOREIGN KEY (`billPayerId`) REFERENCES `user` (`id`) ON    DELETE NO ACTION ON UPDATE NO ACTION
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=latin1;
/*!40101 SET character_set_client = @saved_cs_client */;

DROP TABLE IF EXISTS `billsimpleentry`;
/*!40101 SET @saved_cs_client     = @@character_set_client */;
/*!40101 SET character_set_client = utf8 */;
CREATE TABLE `billsimpleentry` (
  `..` varchar(200) DEFAULT NULL,
  `..` text,
  `billId` bigint(20) DEFAULT NULL,
  `id` bigint(20) NOT NULL AUTO_INCREMENT,
  PRIMARY KEY (`id`),
  KEY `fk_bill_idx` (`billId`)
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=latin1;

JPA-config（oneToOne关系属性的bill Entity中的片段）。

@OneToOne(cascade=CascadeType.ALL,mappedBy="billId",fetch = FetchType.EAGER)
private BillSimpleEntry billSimpleEntry;

我正试图通过BillSimpleEntry.billId和Bill在Bill和BillSimpleEntry之间进行Join。Id.但是我好像搞错了。

这是我得到的错误-

Caused by: org.hibernate.AnnotationException: Referenced property not a (One|Many)ToOne:
com.uh.br.domain.BillSimpleEntry.billId in mappedBy of    
com.uh.br.domain.Bill.billSimpleEntryry

以下是实体

Bill.java
@Entity
@Table(name = "bill")
public class Bill implements GenericObject {
/**
 *
 */
private static final long serialVersionUID = -5660869020353250221L;
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)  
private Long id;
...
..
@OneToOne(cascade=CascadeType.ALL,fetch = FetchType.EAGER)
@JoinColumn(name="billId")
private BillSimpleEntry billSimpleEntry;
...
getters & setters
...
}
BillSimpleEntry.java
@Entity
@Table(name="billsimpleentry")
public class BillSimpleEntry  implements GenericObject{
@Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)  
    private Long id;
    private Long billId;
    @Column(columnDefinition="TEXT")
private String itemDescription;//napkin
...
...
    ...
getters & setters
...

Answer 1

mappedBy属性仅对bidirectional关系是必需的，此元素可以在注释中省略。它用于源实体，指向目标实体上定义关系的字段（包含@JoinColumn）。

@JoinColumn注释应放在billSimpleEntry字段上，以定义应用于连接两个表的列。在OneToOne的情况下，以下适用：

如果联接用于使用外键的OneToOne或ManyToOne映射映射策略，外键列在源的表中实体或可嵌入的。

下面是一个代码示例：

@OneToOne(cascade=CascadeType.ALL,fetch = FetchType.EAGER)
@JoinColumn(name="id")
private BillSimpleEntry billSimpleEntry;

此外，如果Bill将包含SimpleBillEntry字段，则BILL表应包含billsimpleentry表的外键。