帮助解决休眠中的异常

Question

我将此 POJO 映射到我的 MySQL 数据库：

@Entity
@Table(name = "participantespresentes", catalog = "tagit")
public class Participantespresentes implements java.io.Serializable {

    private ParticipantespresentesId id;
    private Evento evento;
    private Usuario usuario;
    private boolean status;

    public Participantespresentes() {
    }

    public Participantespresentes(ParticipantespresentesId id, Evento evento, Usuario usuario, boolean status) {
        this.id = id;
        this.evento = evento;
        this.usuario = usuario;
        this.status = status;
    }

    @EmbeddedId
    @AttributeOverrides({
        @AttributeOverride(name = "idUsuario", column =
        @Column(name = "idUsuario", nullable = false)),
        @AttributeOverride(name = "idEvento", column =
        @Column(name = "idEvento", nullable = false))})
    public ParticipantespresentesId getId() {
        return this.id;
    }

    public void setId(ParticipantespresentesId id) {
        this.id = id;
    }

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "idEvento", nullable = false, insertable = false, updatable = false)
    public Evento getEvento() {
        return this.evento;
    }

    public void setEvento(Evento evento) {
        this.evento = evento;
    }

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "idUsuario", nullable = false, insertable = false, updatable = false)
    public Usuario getUsuario() {
        return this.usuario;
    }

    public void setUsuario(Usuario usuario) {
        this.usuario = usuario;
    }

    @Column(name = "status", nullable = false)
    public boolean isStatus() {
        return this.status;
    }

    public void setStatus(boolean status) {
        this.status = status;
    }
}

每次我尝试使用 hibernate 执行任何操作时，都会启动此异常：

Initial SessionFactory creation failed.org.hibernate.AnnotationException: Collection has neither generic type or OneToMany.targetEntity() defined: com.bytecode.entities.Evento.participantespresentes

有帮助吗？

此致， 瓦尔特·恩里克.

Answer 1

异常消息非常清楚 - Hibernate 无法确定集合 Evento.participantespresentes 的元素类型。您需要将其声明为通用（即 List）。

Answer 2

问题不在于 Participantespresentes，而在于 Evento 类。您有一个名为participantespresentes的属性，但它没有正确映射。如果没有发现问题，请贴出Evento的代码。