小编Yur*_*huk的帖子

我有一个小的学习项目，比如测验 API。当我尝试保存复杂对象（考试）时，hibernate 会抛出 EntityExistsException。我使用 dto (CreateExamRequestDto) 获得 REST 请求，然后我将此 dto 映射到一个实体并使用 Spring Data JPA 保存它。

这是我的实体类：

考试实体：

@Entity
@Table(name = "exams", uniqueConstraints = {@UniqueConstraint(columnNames = {
        "name",
        "category_id"
})})
public class Exam extends AbstractEntity {
    @Id
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "exams_seq_gen")
    @SequenceGenerator(name = "exams_seq_gen", sequenceName = "exams_id_seq")
    @Column(name = "id")
    private Integer id;
    @Column(name = "name", nullable = false)
    private String name;
    @ManyToOne
    @JoinColumn(name = "category_id", nullable = false)
    private Category category;
    @ManyToOne
    @JoinColumn(name = "owner_id", nullable = false) …