Java 实体类中的属性具有mappedBy值，该值在其所属实体中不存在

Article.foo

有什么问题导致：

异常描述：实体类[class net.bounceme.dur.usenet.model.Article]中的属性[foos]有一个mappedBy值[foos]，该值在其所属实体类[class net.bounceme.dur.usenet.model.foo]中不存在。

Foo

没有mappedBy值foos，这是正确的读数吗？这是因为

Foo

的mappedBy值为：

@manytomy（mappedBy=“articles”）

如何修复这些实体，使其成为多对多

我试图遵循以下原则：

示例1：
//在客户类别中：
@许多
@JoinTable（name=“客户电话”）
公共设置getPhones（）{return phones；}
//在PhoneNumber类中：
@许多（mappedBy=“电话”）
公共集getCustomers（）{return customers；}

为什么关系的注释在方法上而不是字段上？这似乎把我搞得一团糟，因为我不确定我的代码应该在哪个实体中包含哪些字段

在尝试了上述方法后，我按照IDE的建议做了一些更改，结果是：

堆栈：

Jul 30, 2012 3:49:47 AM net.bounceme.dur.usenet.driver.Main main
SEVERE: null
Local Exception Stack: 
Exception [EclipseLink-30005] (Eclipse Persistence Services - 2.3.0.v20110604-r9504): org.eclipse.persistence.exceptions.PersistenceUnitLoadingException
Exception Description: An exception was thrown while searching for persistence archives with ClassLoader: sun.misc.Launcher$AppClassLoader@18ad9a0
Internal Exception: javax.persistence.PersistenceException: Exception [EclipseLink-28018] (Eclipse Persistence Services - 2.3.0.v20110604-r9504): org.eclipse.persistence.exceptions.EntityManagerSetupException
Exception Description: Predeployment of PersistenceUnit [USENETPU] failed.
Internal Exception: Exception [EclipseLink-7154] (Eclipse Persistence Services - 2.3.0.v20110604-r9504): org.eclipse.persistence.exceptions.ValidationException
Exception Description: The attribute [foos] in entity class [class net.bounceme.dur.usenet.model.Article] has a mappedBy value of [foos] which does not exist in its owning entity class [class net.bounceme.dur.usenet.model.Foo]. If the owning entity class is a @MappedSuperclass, this is invalid, and your attribute should reference the correct subclass.
    at org.eclipse.persistence.exceptions.PersistenceUnitLoadingException.exceptionSearchingForPersistenceResources(PersistenceUnitLoadingException.java:126)
    at org.eclipse.persistence.jpa.PersistenceProvider.createEntityManagerFactory(PersistenceProvider.java:115)
    at javax.persistence.Persistence.createEntityManagerFactory(Unknown Source)
    at javax.persistence.Persistence.createEntityManagerFactory(Unknown Source)
    at net.bounceme.dur.usenet.driver.Main.<init>(Main.java:34)
    at net.bounceme.dur.usenet.driver.Main.main(Main.java:24)
Caused by: javax.persistence.PersistenceException: Exception [EclipseLink-28018] (Eclipse Persistence Services - 2.3.0.v20110604-r9504): org.eclipse.persistence.exceptions.EntityManagerSetupException
Exception Description: Predeployment of PersistenceUnit [USENETPU] failed.
Internal Exception: Exception [EclipseLink-7154] (Eclipse Persistence Services - 2.3.0.v20110604-r9504): org.eclipse.persistence.exceptions.ValidationException
Exception Description: The attribute [foos] in entity class [class net.bounceme.dur.usenet.model.Article] has a mappedBy value of [foos] which does not exist in its owning entity class [class net.bounceme.dur.usenet.model.Foo]. If the owning entity class is a @MappedSuperclass, this is invalid, and your attribute should reference the correct subclass.
    at org.eclipse.persistence.internal.jpa.EntityManagerSetupImpl.predeploy(EntityManagerSetupImpl.java:1385)
    at org.eclipse.persistence.internal.jpa.deployment.JPAInitializer.callPredeploy(JPAInitializer.java:98)
    at org.eclipse.persistence.jpa.PersistenceProvider.createEntityManagerFactory(PersistenceProvider.java:105)
    ... 4 more

2012年7月30日凌晨3:49:47 net.bounceme.dur.usenet.driver.Main
严重：空
本地异常堆栈：
异常[EclipseLink-30005]（Eclipse持久性服务-2.3.0.v20110604-r9504）：org.Eclipse.Persistence.exceptions.PersistenceUnitLoadingException
异常描述：使用ClassLoader:sun.misc.Launcher搜索持久性存档时引发异常$AppClassLoader@18ad9a0
内部异常：javax.persistence.PersistenceException:Exception[EclipseLink-28018]（Eclipse持久性服务-2.3.0.v20110604-r9504）：org.Eclipse.persistence.exceptions.EntityManagerSetupException
异常描述：PersistenceUnit[USENETPU]的预部署失败。
内部异常：异常[EclipseLink-7154]（Eclipse持久性服务-2.3.0.v20110604-r9504）：org.Eclipse.Persistence.exceptions.ValidationException
异常描述：实体类[class net.bounceme.dur.usenet.model.Article]中的属性[foos]具有mappedBy值[foos]，该值在其所属实体类[class net.bounceme.dur.usenet.model.Foo]中不存在。如果拥有的实体类是@MappedSuperclass，则这是无效的，并且您的属性应该引用正确的子类。
在org.eclipse.persistence.exceptions.PersistenceUnitLoadingException.exceptionSearchingForPersistenceResources（PersistenceUnitLoadingException.java:126）上
位于org.eclipse.persistence.jpa.PersistenceProvider.createEntityManagerFactory（PersistenceProvider.java:115）
位于javax.persistence.persistence.createEntityManagerFactory（未知源）
位于javax.persistence.persistence.createEntityManagerFactory（未知源）
位于net.bounceme.dur.usenet.driver.Main.（Main.java:34）
位于net.bounceme.dur.usenet.driver.Main.Main（Main.java:24）
原因：javax.persistence.PersistenceException:Exception[EclipseLink-28018]（Eclipse持久性服务-2.3.0.v20110604-r9504）：org.Eclipse.persistence.exceptions.EntityManagerSetupException
异常描述：PersistenceUnit[USENETPU]的预部署失败。
内部异常：异常[EclipseLink-7154]（Eclipse持久性服务-2.3.0.v20110604-r9504）：org.Eclipse.Persistence.exceptions.ValidationException
异常描述：实体类[class net.bounceme.dur.usenet.model.Article]中的属性[foos]具有mappedBy值[foos]，该值在其所属实体类[class net.bounceme.dur.usenet.model.Foo]中不存在。如果拥有的实体类是@MappedSuperclass，则这是无效的，并且您的属性应该引用正确的子类。
位于org.eclipse.persistence.internal.jpa.EntityManagerSetupImpl.predeploy（EntityManagerSetupImpl.java:1385）
在org.eclipse.persistence.internal.jpa.deployment.jpainInitializer.callPredeploy上（jpainInitializer.java:98）
位于org.eclipse.persistence.jpa.PersistenceProvider.createEntityManagerFactory（PersistenceProvider.java:105）
... 4更多

实体条款：

package net.bounceme.dur.usenet.model;

import java.io.Serializable;
import java.util.Set;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.persistence.*;

@Entity
public class Article implements Serializable {

    private static final long serialVersionUID = 1L;
    private static final Logger LOG = Logger.getLogger(Article.class.getName());
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;
    @Column
    private String subject;
    @ManyToMany(mappedBy = "foos")
    private Set<Foo> foos;

    public Article() {
    }

    public Article(Message message) {
        try {
            subject = message.getSubject();
        } catch (MessagingException ex) {
            Logger.getLogger(Article.class.getName()).log(Level.SEVERE, null, ex);
        }
    }

        public Set<Foo> getFoos() {
        return foos;
    }

    public Long getId() {
        return id;
    }

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

    @Override
    public int hashCode() {
        int hash = 0;
        hash += (id != null ? id.hashCode() : 0);
        return hash;
    }

    @Override
    public boolean equals(Object object) {
        // TODO: Warning - this method won't work in the case the id fields are not set
        if (!(object instanceof Article)) {
            return false;
        }
        Article other = (Article) object;
        if ((this.id == null && other.id != null) || (this.id != null && !this.id.equals(other.id))) {
            return false;
        }
        return true;
    }

    @Override
    public String toString() {
        return subject;
    }

    public String getSubject() {
        return subject;
    }

    public void setSubject(String subject) {
        this.subject = subject;
    }
}

package net.bounceme.dur.usenet.model；
导入java.io.Serializable；
导入java.util.Set；
导入java.util.logging.Level；
导入java.util.logging.Logger；
导入javax.mail.Message；
导入javax.mail.MessaginException；
导入javax.persistence.*；
@实体
公共类文章实现了可序列化{
私有静态最终长serialVersionUID=1L；
私有静态最终记录器LOG=Logger.getLogger（Article.class.getName（））；
@身份证
@GeneratedValue（策略=GenerationType.AUTO）
私人长id；
@纵队
私有字符串主题；
@许多（mappedBy=“foos”）
私人设置foos；
公共物品（）{
}
公开文章（信息）{
试一试{
subject=message.getSubject（）；
}捕获（消息例外）{
getLogger.getLogger（Article.class.getName（））.log（Level.SEVERE，null，ex）；
}
}
公共集getFoos（）{
返回foos；
}
公共长getId（）{
返回id；
}
公共无效集合id（长id）{
this.id=id；
}
@凌驾
公共int hashCode（）{
int hash=0；
hash+=（id！=null？id.hashCode（）：0）；
返回散列；
}
@凌驾
公共布尔等于（对象）{
//TODO:警告-如果未设置id字段，此方法将不起作用
if（！（物品的对象实例））{
返回false；
}
第条其他=（条）对象；
如果（（this.id==null&&other.id！=null）| |（this.id！=null&&！this.id.equals（other.id）））{
返回false；
}
返回true；
}
@凌驾
公共字符串toString（）{
返回主题；
}
公共字符串getSubject（）{
返回主题；
}
public void setSubject（字符串主题）{
this.subject=主语；
}
}

package net.bounceme.dur.usenet.model;

import java.io.Serializable;
import java.util.Set;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.persistence.*;

@Entity
public class Article implements Serializable {

    private static final long serialVersionUID = 1L;
    private static final Logger LOG = Logger.getLogger(Article.class.getName());
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;
    @Column
    private String subject;
    @ManyToMany(mappedBy = "foos")
    private Set<Foo> foos;

    public Article() {
    }

    public Article(Message message) {
        try {
            subject = message.getSubject();
        } catch (MessagingException ex) {
            Logger.getLogger(Article.class.getName()).log(Level.SEVERE, null, ex);
        }
    }

        public Set<Foo> getFoos() {
        return foos;
    }

    public Long getId() {
        return id;
    }

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

    @Override
    public int hashCode() {
        int hash = 0;
        hash += (id != null ? id.hashCode() : 0);
        return hash;
    }

    @Override
    public boolean equals(Object object) {
        // TODO: Warning - this method won't work in the case the id fields are not set
        if (!(object instanceof Article)) {
            return false;
        }
        Article other = (Article) object;
        if ((this.id == null && other.id != null) || (this.id != null && !this.id.equals(other.id))) {
            return false;
        }
        return true;
    }

    @Override
    public String toString() {
        return subject;
    }

    public String getSubject() {
        return subject;
    }

    public void setSubject(String subject) {
        this.subject = subject;
    }
}

package net.bounceme.dur.usenet.model;

import java.io.Serializable;
import java.util.Set;
import javax.persistence.*;

@Entity
public class Foo implements Serializable {

    private static final long serialVersionUID = 1L;
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;
    @ManyToMany(mappedBy = "articles")
    private Set<Article> articles;

    public Foo() {
    }

        public Set<Article> getArticles() {
        return articles;
    }

        public Long getId() {
        return id;
    }

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

    @Override
    public int hashCode() {
        int hash = 0;
        hash += (id != null ? id.hashCode() : 0);
        return hash;
    }

    @Override
    public boolean equals(Object object) {
        // TODO: Warning - this method won't work in the case the id fields are not set
        if (!(object instanceof Foo)) {
            return false;
        }
        Foo other = (Foo) object;
        if ((this.id == null && other.id != null) || (this.id != null && !this.id.equals(other.id))) {
            return false;
        }
        return true;
    }

    @Override
    public String toString() {
        return "net.bounceme.dur.usenet.model.Foos[ id=" + id + " ]";
    }
}

@ManyToMany(mappedBy = "foos")
private Set<Foo> foos;

public class Article {
    @ManyToMany
    @JoinTable(...)
    private Set<Foo> foos;
}


public class Foo {
    @ManyToMany(mappedBy = "foos")
    private Set<Article> articles;
}

public class Article {
    @ManyToMany(mappedBy = "articles")
    private Set<Foo> foos;
}


public class Foo {
    @ManyToMany
    @JoinTable(...)
    private Set<Article> articles;
}