Question

我正在尝试创建一个“简单”的OneToMany和ManyToOne关系。我得到以下例外：

引起：java.lang.ClassCastException： org.hibernate.mapping.ManyToOne无法强制转换为 org.hibernate.mapping.Component at org.hibernate.mapping.PersistentClass.getRecursiveProperty（PersistentClass.java:464）〜[hibernate-core-5.0.9.Final.jar：5.0.9.Final] at org.hibernate.mapping.PersistentClass.getRecursiveProperty（PersistentClass.java:420）〜[hibernate-core-5.0.9.Final.jar：5.0.9.Final] at org.hibernate.cfg.annotations.CollectionBinder.bindStarToManySecondPass（CollectionBinder.java:758）〜[hibernate-core-5.0.9.Final.jar：5.0.9.Final] at org.hibernate.cfg.annotations.CollectionBinder $ 1.secondPass（CollectionBinder.java:719）〜[hibernate-core-5.0.9.Final.jar：5.0.9.Final] at org.hibernate.cfg.CollectionSecondPass.doSecondPass（CollectionSecondPass.java:54）〜[hibernate-core-5.0.9.Final.jar：5.0.9.Final] at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.processSecondPasses（InFlightMetadataCollectorImpl.java:1655）〜[hibernate-core-5.0.9.Final.jar：5.0.9.Final] at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.processSecondPasses（InFlightMetadataCollectorImpl.java:1623）〜[hibernate-core-5.0.9.Final.jar：5.0.9.Final] at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete（MetadataBuildingProcess.java:278）〜[hibernate-core-5.0.9.Final.jar：5.0.9.Final] at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.metadata（EntityManagerFactoryBuilderImpl.java:847）〜[hibernate-entitymanager-5.0.9.Final.jar：5.0.9.Final] at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build（EntityManagerFactoryBuilderImpl.java:874）〜[hibernate-entitymanager-5.0.9.Final.jar：5.0.9.Final] at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory（SpringHibernateJpaPersistenceProvider.java:60）〜[spring-orm-4.3.2.RELEASE.jar：4.3.2.RELEASE] at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory（LocalContainerEntityManagerFactoryBean.java:338）〜[spring-orm-4.3.2.RELEASE.jar：4.3.2.RELEASE] at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.buildNativeEntityManagerFactory（AbstractEntityManagerFactoryBean.java:373）〜[spring-orm-4.3.2.RELEASE.jar：4.3.2.RELEASE] at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet（AbstractEntityManagerFactoryBean.java:362）〜[spring-orm-4.3.2.RELEASE.jar：4.3.2.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods（AbstractAutowireCapableBeanFactory.java:1637）〜[spring-beans-4.3.2.RELEASE.jar：4.3.2.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean（AbstractAutowireCapableBeanFactory.java:1574）〜[spring-beans-4.3.2.RELEASE.jar：4.3.2.RELEASE] ... 39个常见帧省略

有人能告诉我我做错了吗？

下面你可以找到我的两个实体。

先谢谢你。

  import javax.persistence.OneToMany;
@Entity
@Table(uniqueConstraints={@UniqueConstraint(columnNames={"questionGroupID","questionID"})})
public class QuestionGroupEntity implements Serializable{

    private static final long serialVersionUID = 1796640204447018439L;

    @Id
    @NotEmpty
    @Column(name="question_group_id")
    private String questionGroupID;

    @NotEmpty
    private String label;


    @NotEmpty
    private String questionID;


    @OneToMany(fetch=FetchType.EAGER,targetEntity=QuestionGroupMappingEntity.class,mappedBy="questionGroup")
    List<QuestionGroupMappingEntity> questionGroupMappings;

和

import javax.persistence.ManyToOne;
    @Entity
    @Table(uniqueConstraints={@UniqueConstraint(columnNames={"questionGroupID","questionID","answerID"})})
    public class QuestionGroupMappingEntity implements Serializable {

        private static final long serialVersionUID = 8437546139229082305L;

        @Id
        @SequenceGenerator(name="groupMappingIDGenerator")
        @GeneratedValue(generator="groupMappingIDGenerator",strategy=GenerationType.AUTO)
        private String groupMappingID;

        @NotEmpty
        private String questionID;

        @NotEmpty
        private String questionGroupID;

        @NotEmpty
        private String answerID;

        @ManyToOne(fetch=FetchType.EAGER)
        @JoinColumn(name="question_group_id")
        private QuestionGroupEntity questionGroup;

Answer 1

感谢您的回答。我通过添加这些属性解决了这个问题 spring.jpa.hibernate.ddl-AUTO =更新 spring.jpa.generate-DDL =真问题是spring-data无法更新架构。

Answer 2

请检查您的QuestionGroupEntity实体，private String questionGroupID;配置列名称＆＃34; question_group_id＆＃34;，但您仍然添加@UniqueConstraint(columnNames={"questionGroupID","questionID"})}＆＃34; questionGroupID＆＃34;列，将解除异常

引起：org.hibernate.AnnotationException：无法在表question_group_entity上创建唯一键约束（questionGroupID，questionID）：数据库列＆＃39; questionGroupID＆＃39;未找到。确保使用正确的列名，这取决于使用的命名策略（它可能与实体中的属性名称不同，特别是对于关系类型） at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.buildUniqueKeyFromColumnNames（InFlightMetadataCollectorImpl.java:2090） at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.buildUniqueKeyFromColumnNames（InFlightMetadataCollectorImpl.java:1965） at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.processUniqueConstraintHolders（InFlightMetadataCollectorImpl.java:1953） at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.processSecondPasses（InFlightMetadataCollectorImpl.java:1629）在org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete（MetadataBuildingProcess.java:278）在org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.metadata（EntityManagerFactoryBuilderImpl.java:847）在org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build（EntityManagerFactoryBuilderImpl.java:874）

修复此问题后，可以使用spring boot 1.4

ManyToOne ClassCastException

2 个答案: