使用MappedSuperclass

Question

环境：

• javaee 7
• java 8
• jpa 2

当我查询Moviment时，我得到了错误EntityNotFoundException，并且在我修改Espai类以使用注释@MappedSuperclass在单独的类中分隔id和版本后，我自动尝试加载相关的Espai。

我可以怀疑它是与equals（）和hashCode（）方法相关的东西，但我无法弄清楚问题。

Espai工作正常

@Entity
@Table(name = "a_espai")
public class Espai implements Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Integer id;

    private String nom;
    private Integer version;

    @ManyToOne
    @JoinColumn(name = "idServei", referencedColumnName = "id")
    private Servei servei;

    ...

    @Override
    public int hashCode() {
        int hash = servei == null ? 1 : servei.getId();
        return hash;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }

        if (obj == null) {
            return false;
        }

        if (!(obj instanceof Espai)) {
            return false;
        }

        Espai other = (Espai) obj;
        return id != null && id.equals(other.getId());
    }
}

更改后的Espai会引发错误

@Entity
@Table(name = "a_espai")
public class Espai extends BaseEntity implements Serializable {

    private String nom;

    @ManyToOne
    @JoinColumn(name = "idServei", referencedColumnName = "id")
    private Servei servei;

    @Override
    public int hashCode() {
        int hash = 0;

        if (servei == null) {
            return hash;
        } else {
            return servei.getId();
        }
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }

        if (obj == null) {
            return false;
        }

        if (!(obj instanceof Espai)) {
            return false;
        }

        Espai other = (Espai) obj;
        return getId() != null && getId().equals(other.getId());
    }
}

Espai在急切加载时遇到错误的移动课

@Entity
@Table(name = "t_moviment")
public class Moviment extends BaseEntity implements Serializable {

    private LocalDate dataInici;
    private LocalDate dataFi;
    private String observacio;

    @ManyToOne
    @Basic(optional = false)
    @JoinColumn(name = "idEspai", referencedColumnName = "id")
    private Espai espai;
    ...
}


**Espai before change that provokes the error**

    @MappedSuperclass
    public class BaseEntity {

        @Id
        @GeneratedValue(strategy = GenerationType.IDENTITY)
        private Integer id;

        @Version
        protected Integer version;

        public Integer getId() {
            return id;
        }    
    }