java - 使用@OneToOne属性设置对象可以，但不适用于@ManyToMany对象

Question

这是我的两个类的代码：

@Entity
public class FicheMetier implements Serializable {

    private static final long serialVersionUID = 1L;
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private int Id;
    private String Name;
    @OneToOne
    private Employe employe;
    private String description;
    @ManyToOne(cascade = CascadeType.ALL)
    private MatriceComp matricecomp;

@Entity
public class MatriceComp implements Serializable {

    private static final long serialVersionUID = 1L;
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private int Id;
    @Enumerated(EnumType.STRING)
    @NotNull
    private Category category;
    private String Description;
    @ManyToMany(cascade = CascadeType.ALL)
    private List<Competance> competances;

这是我正在尝试运行的服务：

@Override
public void affecterMat(MatriceComp matrice,FicheMetier ficheMetier) {

    FicheMetier us= em.find(FicheMetier.class,ficheMetier.getId());

    us.setMatricecomp(matrice.getId());

} 

当我尝试使用矩阵设置属性@ManyToOne matricecomp时，我得到EJBTransactionRolledbackException。
但是！如果将其更改为@OneToOne matricecomp，并且我使用matrice设置了属性，则可以正常工作

Answer 1

用这种方式

@ManyToMany(cascade = CascadeType.ALL)
@JoinTable(name = "MatriceComp_Competance",
        joinColumns = { @JoinColumn(name = "id") },
        inverseJoinColumns = { @JoinColumn(name = "id") })
private List<Competance> MatriceCompCompetances= new ArrayList<Competance>();