Question

我有一个指向postgresql表的实体类。下面是表结构。 Paymentreferencenumber是由触发器填充的PK。 id字段是序列生成的字段。当我尝试使用JPARepository保存方法保存在此表中时，它将插入第一条记录。但是之后，由于主键约束，它失败了。由于PK是字符串类型并使用触发器生成，因此我将生成器策略指定为“选择”。任何人都可以帮我解决这个障碍，并指出正确的方向。谢谢

表结构-

custId serial not null,
    paymentreferencenumber varchar(32) not null
        constraint customers1_pkey
            primary key,
    firstname varchar(255),
    lastname varchar(255)

Entity class --
@Entity
@Table(name = "customersnew")
public class Customer implements Serializable {

    private static final long serialVersionUID = -1L;


    @GeneratedValue(generator = "seq")
    @GenericGenerator(name="seq", strategy="sequence", parameters = { @Parameter(name="key", value = "customersnew_custid_seq")})
    @Column(name = "custid")
    private long id;

    @Id
    @GeneratedValue(generator = "trigger_generated")
    @GenericGenerator(name="trigger_generated", strategy="select", parameters = { @Parameter(name="key", value = "id")})
    @Column(name = "paymentreferencenumber")
    private String refNum;

    @Column(name = "firstname")
    private String firstName;

    @Column(name = "lastname")
    private String lastName;

}

--- Controller using JPA save

@RestController
public class CustomerController {

    @Autowired
    CustomerRepository repository;

    EntityManagerFactory emf;

    public CustomerController(CustomerRepository repository, EntityManagerFactory emf) {
        this.repository = repository;
        this.emf = emf;
    }

    @PostMapping("/create")
    public String create(@RequestBody CustomerUI customer){
        // save a single Customer

        Customer returnObj = repository.saveAndFlush(new Customer(customer.getFirstName(), customer.getLastName()));

        PersistenceUnitUtil util = emf.getPersistenceUnitUtil();

        Object retObj = util.getIdentifier(returnObj);

        return "Customer is created";
    }

Answer 1

如果您未指定ID生成策略，则Hibernate将使用GenerationType.AUTO。这将导致

AUTO-标识列，序列或表，具体取决于基础数据库。

如果您查看here，您会注意到所有生成long，short或int类型而不是String类型的ID的人。

假设您想要一个String UUID作为ID，则可以使用

@Id
@GeneratedValue(generator = "uuid")
@GenericGenerator(name = "uuid", strategy = "uuid2")
@Column(name = "paymentreferencenumber")
private String refNum;

JPA存储库在保存后检索自定义主键值

1 个答案: