我有以下问题:
我有一个带有复合主键的基类(用作超类)。现在我正在尝试从基类正确设置子类,但这不起作用!有人可以帮我吗?谢谢
这是我的课程:
BasePK.java
@Embeddable
public class BasePK implements Serializeable {
protected String base1;
protected Timestamp base2;
..
}
Base.java
@MappedSuperclass
@Inheritance(strategy=InheritanceType.TABLE_PER_CLASS)
public abstract class Base implements Serializeable {
@EmbeddedId
protected BasePK id;
..
}
子类A.java
@Entity
public class SubClassA extends Base implements Serializeable {
@OneToMany(cascade=CascadeType.ALL, fetch=FetchType.EAGER, mappedBy="attrA")
protected List<SubClassB> attrsB;
protected String attrA1;
protected String attrA2;
..
}
子类B.java
@Entity
public class SubClassB extends Base implements Serializeable {
@ManyToOne(fetch=FetchType.LAZY)
private SubClassA attrA;
protected String attrB1;
protected String attrB2;
..
}
子类C.java
@Entity
public class SubClassC extends SubClassA implements Serializeable {
protected String attrC1;
protected String attrC2;
..
}
当我尝试运行该项目时,会出现以下异常:
[EL Info]: 2012-11-01 23:31:18.739--ServerSession(2063330336)--EclipseLink, version: Eclipse Persistence Services - 2.4.1.v20121003-ad44345
[EL Warning]: metadata: 2012-11-01 23:31:19.199--ServerSession(2063330336)--Reverting the lazy setting on the OneToOne or ManyToOne attribute [controlledObject] for the entity class [class logyourlife.entities.ChangeRecord] since weaving was not enabled or did not occur.
[EL Severe]: 2012-11-01 23:31:19.229--ServerSession(2063330336)--Exception [EclipseLink-0] (Eclipse Persistence Services - 2.4.1.v20121003-ad44345): org.eclipse.persistence.exceptions.IntegrityException
Descriptor Exceptions:
---------------------------------------------------------
Exception [EclipseLink-48] (Eclipse Persistence Services - 2.4.1.v20121003-ad44345): org.eclipse.persistence.exceptions.DescriptorException
Exception Description: Multiple writable mappings exist for the field [SUBCLASSB.BASE1]. Only one may be defined as writable, all others must be specified read-only.
Mapping: org.eclipse.persistence.mappings.ManyToOneMapping[attrA]
Descriptor: RelationalDescriptor(test.entities.SubClassB --> [DatabaseTable(SUBCLASSB)])
Exception [EclipseLink-48] (Eclipse Persistence Services - 2.4.1.v20121003-ad44345): org.eclipse.persistence.exceptions.DescriptorException
Exception Description: Multiple writable mappings exist for the field [SUBCLASSB.BASE2]. Only one may be defined as writable, all others must be specified read-only.
Mapping: org.eclipse.persistence.mappings.ManyToOneMapping[attrA]
Descriptor: RelationalDescriptor(test.entities.SubClassB --> [DatabaseTable(SUBCLASSB)])
仅供参考:equals 和 hashcode 方法在所有类中都被覆盖。