Spring JPA带id保存时报错：detached entity passed to persist

陈不二692025-08-08 9:34

问题:

因项目JDK升级从11升到21，相应的Spring从2.x升级到3.x，Hiberante也从5.x升级到6.6. 然后在测试时发现如下代码报错

实体类User对应表users

java 复制代码

@Data
@Entity
@Table(name = "users")
public class User {
    @Id
    @GeneratedValue(generator = "customerUUIDGenerator")
    @GenericGenerator(
            name = "customerUUIDGenerator",
            strategy = "org.example.id.customerUUIDGenerator"
    )
    private UUID id;

    @Version
    private int version;

    @Column(unique = true, nullable = false)
    private String username;

}

自定义id生成器

java 复制代码

public class CustomerUUIDGenerator implements IdentifierGenerator {
    
    @Override
    public Object generate(SharedSessionContractImplementor session, Object object) {
        final EntityPersister entityPersister = session.getEntityPersister( null, object );
		Object id = entityPersister.getIdentifier( object, session );
        return null != id ? id : UUID.randomUUID();
    }
}

代码中存在如下使用

java 复制代码

    ...
    public void addUser(UUID id, String name, String passwd) {
        User user = new User();
        user.setId(id);
        user.setUsername(name);
        userRepository.save(user);
        
    }

上面代码报错: detached entity passed to persist 或者StaleObjectStateException

原因

Hibernate在保存时会先查数据库有没有该数据

如果无则判断实体是否新创建的，判断流程主要如下

先判断id是否为空
如果version为null且id为外键
依据unsavedStrategy判断,尽在返回false时报错，否则存入数据库

id == null 则为true
id为自定义id且该Generator的allowAssignedIdentifiers方法返回true,则返回null