字符串列数据从JPA变为Null

Question

我正在使用休眠来持久化实体。但是，即使实体包含指定的字段值，数据也将以null形式持久保存。

@RestController
@RequestMapping("example")
public class Controller {

@Autowired
EntityManager entityManager;

@RequestMapping("/getData")
@Transactional
public void getData() {

    Members member = new Members();
    member.firstName= "SRC";
    member.lastName = "Code";
    member.major = "Computer Science";
    member.ID = 424;

    entityManager.persist(member);
}

会员班

 @Entity
    @Table(name = "members")
    public class Members {


    @Id
    public int ID;
    public String major;

    @Column(name = "firstName" , nullable = false)
    @Length(min = 0, max =20)
    public String firstName;


    @Length(min = 0, max =20)
    @Column(name = "lastName" , nullable = false)
    public String lastName;
}

但是数据库表中的数据正在获取firstName和LastName fields. But the ID and major is correctly persisted.的空值