Question

我在下面创建了两个表。

TableOne
   id pk
   code varchar (references a column in TableTwo, non unique)

TableTwo
   id pk
   code varchar (referenced in TableOne, non unique)
   option

在表1中，一个id只能有一个代码。在表2中，代码可以重复以用于不同的选项。即代码+选项将是唯一的（不是我在DB中定义了约束）。

现在，我有我的实体类，如下所述

@Entity
@Table(name = "TableOne")
public class Table1 {
   @Id
   @Column(name = "id")
   private String id;

   @OneToMany(mappedBy = "table1", fetch = FetchType.EAGER)
   private List<Table2> table2s;
}

@Entity
@Table(name = "TableTwo")
public class Table2 {
   @Id
   @Column(name = "id")
   private String id;

   @ManyToOne
   @JoinColumn(name = "code", referencedColumnName = "code", nullable = false, insertable = false, updatable = false)
   private Table1 table1;
}

当我尝试执行我的应用程序时，它会出现以下错误

org.springframework.orm.jpa.JpaSystemException: Found shared references to a collection: model.Table1.table2s; nested exception is org.hibernate.HibernateException: Found shared references to a collection: model.Table1.table2s
at org.springframework.orm.jpa.vendor.HibernateJpaDialect.convertHibernateAccessException(HibernateJpaDialect.java:333) ~[spring-orm-4.3.12.RELEASE.jar:4.3.12.RELEASE]
at org.springframework.orm.jpa.vendor.HibernateJpaDialect.translateExceptionIfPossible(HibernateJpaDialect.java:244) ~[spring-orm-4.3.12.RELEASE.jar:4.3.12.RELEASE]
at org.springframework.orm.jpa.JpaTransactionManager.doCommit(JpaTransactionManager.java:521) ~[spring-orm-4.3.12.RELEASE.jar:4.3.12.RELEASE]
at org.springframework.transaction.support.AbstractPlatformTransactionManager.processCommit(AbstractPlatformTransactionManager.java:761) [spring-tx-4.3.12.RELEASE.jar:4.3.12.RELEASE]
at org.springframework.transaction.support.AbstractPlatformTransactionManager.commit(AbstractPlatformTransactionManager.java:730) [spring-tx-4.3.12.RELEASE.jar:4.3.12.RELEASE]
at org.springframework.transaction.interceptor.TransactionAspectSupport.commitTransactionAfterReturning(TransactionAspectSupport.java:504) [spring-tx-4.3.12.RELEASE.jar:4.3.12.RELEASE]
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:292) [spring-tx-4.3.12.RELEASE.jar:4.3.12.RELEASE]
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96) [spring-tx-4.3.12.RELEASE.jar:4.3.12.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) [spring-aop-4.3.12.RELEASE.jar:4.3.12.RELEASE]
at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92) [spring-aop-4.3.12.RELEASE.jar:4.3.12.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) [spring-aop-4.3.12.RELEASE.jar:4.3.12.RELEASE]
at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:673) [spring-aop-4.3.12.RELEASE.jar:4.3.12.RELEASE]
at au.th.api.assessment.service.MasterQuestionsServiceImpl$$EnhancerBySpringCGLIB$$e50ce6a4.getQuestionById(<generated>) [classes/:na]

TableOne中有两行具有相同的代码。 TableTwo只有一行代码。

有人可以帮忙吗？

修改

如果我删除 referencedColumnName ，它可以正常工作，但列表为空。

在调试时，我可以看到列表对象在提交事务之前被提取为PersistentBag。在提交时，它会抛出异常。异常之前打印的错误是

o.h.i.ExceptionMapperStandardImpl        : HHH000346: Error during managed flush [org.hibernate.HibernateException: Found shared references to a collection: model.Table1.table2s]

Answer 1

您对OneToMany关系有误。请参阅下面的示例。

@Entity
@Table(name = "course")
public class Course  implements Serializable{

    private int id;
    private Set<Student> students;

    public Course(){ 
    }     

    @OneToMany(mappedBy = "course", cascade = CascadeType.ALL)
    public Set<Student> getStudents() {
        return students;
    }
}

@Entity
public class Student implements Serializable{

    private int id;
    private Course course;

    @ManyToOne
    @JoinColumn(name = "course_id")
    public Course getCourse() {
        return course;
    }
}

您可以在帖子OneToMany relationship

中找到工作示例

Hibernate OneToMany列表映射问题

1 个答案: