java @OnetoMany 类调用
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@OnetoMany class call
提问by stefanuzz
i need some help for my class...
我的课需要一些帮助...
package com.it.ese.orbit.entity;
import javax.persistence.*;
import java.util.List;
/**
* Created by IntelliJ IDEA.
* User: Shahriar Newaz
* Date: 07/03/11
* Time: 10.07
*/
@Entity
@Inheritance(strategy =InheritanceType.JOINED)
public class OrbitObject {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue
@Column(name="id",nullable = false)
private Long id;
@Column(name="Scenario",nullable = false)
private String scenario; // not sure about how to map scenario
@Column(name="code",nullable = true)
private String code;
@Column(name="name",nullable = true)
private String name;
@OneToOne(cascade=CascadeType.ALL)
private Bia bia;
@OneToOne(cascade=CascadeType.ALL)
public Impatti impatti;
@Column(name="parent",nullable = true)
@OneToMany(cascade=CascadeType.ALL)
private OrbitObject OrbitObject;
public Long getId() {
return id;
}
protected void setId(Long id) {
this.id = id;
}
public String getCode() {
return code;
}
public void setCode(String code) {
this.code = code;
}
public String getScenario() {
return scenario;
}
public void setScenario(String scenario) {
this.scenario = scenario;
}
public String getName() {
return name;
}
public void setName(String name) {
name = name;
}
// LOG
@Override
public String toString(){
return "com.it.ese.orbit.models.OrbitObject["
+ " - name="+name + " - scenario="+scenario +" - id= "+id+"]";
}
}
But i get thi error...
但我得到这个错误...
Caused by: org.hibernate.AnnotationException: Illegal attempt to map a non collection as a @OneToMany, @ManyToMany or @CollectionOfElements: com.it.ese.orbit.entity.OrbitObject.OrbitObject
引起：org.hibernate.AnnotationException：非法尝试将非集合映射为@OneToMany、@ManyToMany 或@CollectionOfElements：com.it.ese.orbit.entity.OrbitObject.OrbitObject
I wish i create an OrbitObject field as like an object of the same class... Help please!
我希望我创建一个 OrbitObject 字段，就像同一类的对象一样......请帮忙！
回答by Edwin Dalorzo
You either do
你要么做
@Column(name="parent",nullable = true)
@ManyToOne(cascade=CascadeType.ALL)
private OrbitObject OrbitObject;
Or
或者
@Column(name="parent",nullable = true)
@OneToMany(cascade=CascadeType.ALL)
private Set<OrbitObject> OrbitObject;
The first case implies this entity will be the owning side, namely, it will have the foreign key.
第一种情况意味着该实体将是拥有方，即，它将拥有外键。
回答by Riccardo Cossu
OneToMany means that OrbitObject has many OrbitObject children, which is not true because the OrbitObject property is not a collection. You must convert it to a ManyToOne
OneToMany 意味着 OrbitObject 有许多 OrbitObject 子项，这是不正确的，因为 OrbitObject 属性不是一个集合。您必须将其转换为多对一
回答by Vladimir Ivanov
you can use @OneToMany referring to a collection of elements, for example
例如，您可以使用 @OneToMany 来指代元素集合
@OneToMany
List<OrbitObject> orbitList;
