: mappedBy 引用了一个未知的目标实体属性

Posted 2023-04-14

【中文标题】: mappedBy 引用了一个未知的目标实体属性

【英文标题】：: mappedBy reference an unknown target entity property

【发布时间】：2013-10-06 10:43:32

【问题描述】：

我正在开发一个使用 hibernate 的简单练习应用程序。它具有简单的映射，就像制造商可以拥有许多手机一样。但是手机只能由单个制造商制造。这是我认为代码应该是的。

package mobileconsumers.entity.dto;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.Table;


@Entity
@Table(name="ms_ref_mobile")
public class MobileDTO 

private Long id;
private String model;
private ManufacturerDTO manufacturerDTO;

@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
@Column(name="MOBILE_ID")
public Long getId() 
    return id;

public void setId(Long id) 
    this.id = id;

public String getModel() 
    return model;

public void setModel(String model) 
    this.model = model;

@ManyToOne(fetch=FetchType.LAZY)
@JoinColumn(name="MANUFACTURER_ID")
public ManufacturerDTO getManufacturer() 
    return manufacturerDTO;

public void setManufacturer(ManufacturerDTO manufacturer) 
    this.manufacturerDTO = manufacturer;

这是第二个 dto

package mobileconsumers.entity.dto;

import java.util.HashSet;
import java.util.Set;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.OneToMany;
import javax.persistence.Table;

@Entity
@Table(name="ms_ref_manufacturer")
public class ManufacturerDTO 

private Long id;
private String name;
private Set<MobileDTO> mobileDTOs = new HashSet<>(0);

@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
@Column(name="MANUFACTURER_ID")
public Long getId() 
    return id;

public void setId(Long id) 
    this.id = id;

@Column(name="NAME")
public String getName() 
    return name;

public void setName(String name) 
    this.name = name;

@OneToMany(fetch=FetchType.LAZY,mappedBy="manufacturerDTO")
public Set<MobileDTO> getMobileDTOs() 
    return mobileDTOs;

public void setMobileDTOs(Set<MobileDTO> mobileDTOs) 
    this.mobileDTOs = mobileDTOs;

当我尝试启动我的服务器时，它给了我一个错误说.. org.hibernate.AnnotationException: mappedBy reference anunknown target entity property: mobileconsumers.entity.dto.MobileDTO.manufacturerDTO in mobileconsumers.entity.dto.ManufacturerDTO.mobileDTOs 映射对我来说似乎很好。我一定错过了一些非常愚蠢的事情。只需要一双新的眼睛来查看我的代码并找出问题所在..

【参考方案1】：

更改mappedBy 的值，使其引用关联的@ManyToOne 一侧的manufacturer 属性：

@OneToMany(fetch=FetchType.LAZY,mappedBy="manufacturer")
public Set<MobileDTO> getMobileDTOs() 
    return mobileDTOs;

【讨论】：

是的。下面的答案告诉我为什么。我认为我在创建 getter 和 setter 时做错了什么。非常感谢..