Question

我正在尝试使用Play2中的EBean建立多对多的关系，我遇到了一个问题，即EBean发出一个错误，说我的类没有注册。继承我的映射类：

@Entity
public class Booking extends Model {
   @Id
   @GeneratedValue(strategy = GenerationType.AUTO)
   private int id;
   //... other fields
}
@Entity
public class Store extends Model {
   @Id
   @GeneratedValue(strategy = GenerationType.AUTO)
   private int id;
   //... other fields
}

@Embeddable
public class ComissionId {
   @ManyToOne(targetEntity = Booking.class, optional = false)
   @PrimaryKeyJoinColumn(name = "booking_id", referencedColumnName = "id")
   private Booking booking;

   @ManyToOne(targetEntity = Store.class, optional = false)
   @PrimaryKeyJoinColumn(name = "store_id", referencedColumnName = "id")
   private Store store;
}

@Entity
@AssociationOverrides({
    @AssociationOverride(name = "id.booking", joinColumns = @JoinColumn(name = "booking_id")),
    @AssociationOverride(name = "id.store", joinColumns = @JoinColumn(name = "store_id"))
 })
 public class StoreComission extends Model {
    @EmbeddedId
    private ComissionId id;
    @Column(nullable = false)
    private double value;
    @Column(nullable = false)
    private Date date;
}

错误：

java.lang.RuntimeException: 
  Error reading annotations for models.ids.ComissionId
  Caused by: java.lang.RuntimeException: 
  Error with association to [class models.Booking] from [models.ids.ComissionId.booking]. 
  Is class models.Booking registered?

在我的application.conf中我放了ebean.default =“models。*”所以所有这些类都应该注册正确吗？（我试图将ComissionId从包models.ids转移到模型，但同样的错误发生了）

Answer 1

由于您的ComissionId类中包含@ManyToOne注释，因此出现此错误。要使此代码工作，您必须将这些关系移动到StoreComission类。在ComissionId类中，您应该只保留标识符。在StoreComission类中，@ ManyToOne关系映射到与复合键中的字段相同的列。但是它们将“可插入”和“可更新”属性设置为false以防止列重复以下是针对上述情况的更正工作代码：

StoreComission类：

@Entity
public class StoreComission extends Model {

    public StoreComission() {
        id = new ComissionId();
    }

    @EmbeddedId
    private ComissionId id;

    @Column(nullable = false)
    public double value;

    @Column(nullable = false)
    public Date date;

    @ManyToOne
    @JoinColumn(name = "booking_id", insertable = false, updatable = false)
    private Booking booking;

    @ManyToOne
    @JoinColumn(name = "store_id", insertable = false, updatable = false)
    private Store store;

    public void setBooking(Booking aBooking) {
        booking = aBooking;
        id.booking_id = aBooking.id;
    }

    public Booking getBooking() {
        return booking;
    }

    public void setStore(Store aStore) {
        store = aStore;
        id.store_id = aStore.id;
    }

    public Store getStore() {
        return store;
    }
}

ComissionId课程：

@Embeddable
public class ComissionId {

    public int booking_id;

    public int store_id;

    @Override
    public int hashCode() {
        return booking_id + store_id;
    }

    @Override
    public boolean equals(final Object obj) {
        return super.equals(obj);
    }
}

JPA和EBean中的多对多

1 个答案: