JPA：如果一列为null，则getResultList（）返回null实体

Question

我使用JPA时遇到了一个奇怪的问题。

在PostgreSQL数据库中，视图（ConsoView）是使用LEFT OUTER JOIN创建的，因此此视图中的某些行在一列或两列中具有空值。

通过Java端的查询请求数据（使用标准Builder，EntityManager和方法getResultList（）），我获得了一个具有正确记录数的列表，但是有完整的空实体而不是实体一个或两个空属性。

更新：添加一些代码

实体ConsoView：

/**
 * ConsoView generated by hbm2java
 */
@Entity
@Table(name = "conso_view")
public class ConsoView implements java.io.Serializable {

    private ConsoViewId id;

    public ConsoView() {
    }

    public ConsoView(ConsoViewId id) {
        this.id = id;
    }

    @EmbeddedId
    @AttributeOverrides({
            @AttributeOverride(name = "nomSite", column = @Column(name = "nom_site", length = 20)),
            @AttributeOverride(name = "day", column = @Column(name = "day", length = 13)),
            @AttributeOverride(name = "dayOfWeek", column = @Column(name = "day_of_week", precision = 131089, scale = 0)),
            @AttributeOverride(name = "valeurConso", column = @Column(name = "valeur_conso", precision = 131089, scale = 0)),
            @AttributeOverride(name = "vacance", column = @Column(name = "vacance")),
            @AttributeOverride(name = "ferie", column = @Column(name = "ferie")) })
    public ConsoViewId getId() {
        return this.id;
    }

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

}

Id：

**
 * ConsoViewId generated by hbm2java
 */
@Embeddable
public class ConsoViewId implements java.io.Serializable {

    private String nomSite;
    private Date day;
    private BigDecimal dayOfWeek;
    private BigDecimal valeurConso;
    private String vacance;
    private String ferie;

    public ConsoViewId() {
    }

    public ConsoViewId(String nomSite, Date day, BigDecimal dayOfWeek,
            BigDecimal valeurConso, String vacance, String ferie) {
        this.nomSite = nomSite;
        this.day = day;
        this.dayOfWeek = dayOfWeek;
        this.valeurConso = valeurConso;
        this.vacance = vacance;
        this.ferie = ferie;
    }

    @Column(name = "nom_site", length = 20)
    public String getNomSite() {
        return this.nomSite;
    }

    public void setNomSite(String nomSite) {
        this.nomSite = nomSite;
    }

    @Column(name = "day", length = 13)
    public Date getDay() {
        return this.day;
    }

    public void setDay(Date day) {
        this.day = day;
    }

    @Column(name = "day_of_week", precision = 131089, scale = 0)
    public BigDecimal getDayOfWeek() {
        return this.dayOfWeek;
    }

    public void setDayOfWeek(BigDecimal dayOfWeek) {
        this.dayOfWeek = dayOfWeek;
    }

    @Column(name = "valeur_conso", precision = 131089, scale = 0)
    public BigDecimal getValeurConso() {
        return this.valeurConso;
    }

    public void setValeurConso(BigDecimal valeurConso) {
        this.valeurConso = valeurConso;
    }

    @Column(name = "vacance")
    public String getVacance() {
        return this.vacance;
    }

    public void setVacance(String vacance) {
        this.vacance = vacance;
    }

    @Column(name = "ferie")
    public String getFerie() {
        return this.ferie;
    }

    public void setFerie(String ferie) {
        this.ferie = ferie;
    }

    public boolean equals(Object other) {
        if ((this == other))
            return true;
        if ((other == null))
            return false;
        if (!(other instanceof ConsoViewId))
            return false;
        ConsoViewId castOther = (ConsoViewId) other;

        return ((this.getNomSite() == castOther.getNomSite()) || (this
                .getNomSite() != null && castOther.getNomSite() != null && this
                .getNomSite().equals(castOther.getNomSite())))
                && ((this.getDay() == castOther.getDay()) || (this.getDay() != null
                        && castOther.getDay() != null && this.getDay().equals(
                        castOther.getDay())))
                && ((this.getDayOfWeek() == castOther.getDayOfWeek()) || (this
                        .getDayOfWeek() != null
                        && castOther.getDayOfWeek() != null && this
                        .getDayOfWeek().equals(castOther.getDayOfWeek())))
                && ((this.getValeurConso() == castOther.getValeurConso()) || (this
                        .getValeurConso() != null
                        && castOther.getValeurConso() != null && this
                        .getValeurConso().equals(castOther.getValeurConso())))
                && ((this.getVacance() == castOther.getVacance()) || (this
                        .getVacance() != null && castOther.getVacance() != null && this
                        .getVacance().equals(castOther.getVacance())))
                && ((this.getFerie() == castOther.getFerie()) || (this
                        .getFerie() != null && castOther.getFerie() != null && this
                        .getFerie().equals(castOther.getFerie())));
    }

    public int hashCode() {
        int result = 17;

        result = 37 * result
                + (getNomSite() == null ? 0 : this.getNomSite().hashCode());
        result = 37 * result
                + (getDay() == null ? 0 : this.getDay().hashCode());
        result = 37 * result
                + (getDayOfWeek() == null ? 0 : this.getDayOfWeek().hashCode());
        result = 37
                * result
                + (getValeurConso() == null ? 0 : this.getValeurConso()
                        .hashCode());
        result = 37 * result
                + (getVacance() == null ? 0 : this.getVacance().hashCode());
        result = 37 * result
                + (getFerie() == null ? 0 : this.getFerie().hashCode());
        return result;
    }

}

DAO中使用的方法：

public List<ConsoView> findAll() {
        CriteriaBuilder cb = em.getCriteriaBuilder();
        CriteriaQuery<ConsoView> criteria = cb.createQuery(ConsoView.class);
        Root<ConsoView> consoView = criteria.from(ConsoView.class);
        criteria.select(consoView);


        return em.createQuery(criteria).getResultList();

    }

可以为null的列是：'vacance'和'ferie'。

你知道这个问题的解决方案吗？

谢谢！

---

修改

我找到了一个有助于解决问题的新信息：

注释@EmbeddedId用于指定主键，因此如果此键的某个字段为null，则返回null实体。

新问题是实体是使用Hibernate自动生成的，即使View没有主键，也会创建@EmbeddedId的部分。

那你怎么认为问题可以解决呢？