Java 日食层次错误
我正在尝试与Virgo和EclipseLink合作,并基于Greenpage项目实现一个应用程序 我已经实现了一个层次结构,但是我得到了一个wierd错误(使用EclipseLink): 层次结构:Java 日食层次错误,java,jpa,eclipselink,eclipse-virgo,Java,Jpa,Eclipselink,Eclipse Virgo,我正在尝试与Virgo和EclipseLink合作,并基于Greenpage项目实现一个应用程序 我已经实现了一个层次结构,但是我得到了一个wierd错误(使用EclipseLink): 层次结构: 实体将注释从访问器移动到字段声明,并将字段可访问性更改为受保护 @MappedSuperclass public abstract class Entity implements Serializable { private static final long serialVersionU
实体将注释从访问器移动到字段声明,并将字段可访问性更改为受保护
@MappedSuperclass
public abstract class Entity implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy=GenerationType.AUTO)
protected Long id;
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
}
好的,Kevin Bowersox的答案告诉我正确的答案:我更改所有受保护的字段,并将注释更改为字段。这将导致良好的工作状态;) 属性访问是一种完全有效的方法。@user872846您能发布新的错误吗?尝试保护抽象类中的所有字段。我怀疑EclipseLink可能需要直接访问字段,而私有作用域阻止了这一点。当然,但对于其他类,例外情况是相同的。我将所有字段更改为“受保护”,但没有成功;(凯文的解决方案中有什么不适合你呢?我看不出有什么不同。
import java.io.Serializable;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.MappedSuperclass;
@MappedSuperclass
public abstract class Entity implements Serializable {
private static final long serialVersionUID = 1L;
private Long id;
@Id
@GeneratedValue(strategy=GenerationType.AUTO)
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
}
import javax.persistence.MappedSuperclass;
@MappedSuperclass
public abstract class NamedEntity extends Entity {
private static final long serialVersionUID = 1L;
private String name;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Override
public String toString() {
return name;
}
}
import javax.persistence.DiscriminatorColumn;
import javax.persistence.Entity;
import javax.persistence.Inheritance;
import javax.persistence.InheritanceType;
import pl.com.mgr.model.NamedEntity;
@Entity
@Inheritance(strategy = InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn(name = "discriminator")
public abstract class Person extends NamedEntity {
private static final long serialVersionUID = 1L;
}
import javax.persistence.Column;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.MappedSuperclass;
import model.NamedEntity;
@MappedSuperclass
public abstract class Attribute<T extends NamedEntity> extends NamedEntity {
private static final long serialVersionUID = 1L;
private T entity;
private String value;
@ManyToOne
@JoinColumn(name = "entity", nullable = false)
public T getEntity() {
return entity;
}
public void setEntity(T entity) {
this.entity = entity;
}
@Column(nullable = false)
public String getValue() {
return value;
}
public void setValue(String value) {
this.value = value;
}
}
import javax.persistence.Entity;
@Entity
public class LecturerAttribute extends Attribute<Lecturer> {
private static final long serialVersionUID = 1L;
}
Internal Exception: Exception [EclipseLink-7161] (Eclipse Persistence Services - 2.0.0.v20091127-r5931): org.eclipse.persistence.exceptions.ValidationException
Exception Description: Entity class [class model.LecturerAttribute] has no primary key specified. It should define either an @Id, @EmbeddedId or an @IdClass. If you have defined PK using any of these annotations then make sure that you do not have mixed access-type (both fields and properties annotated) in your entity class hierarchy.
@MappedSuperclass
public abstract class Entity implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy=GenerationType.AUTO)
protected Long id;
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
}