Spring 和 Hibernate3 的 @Embeddable 问题

Posted 2023-04-14

【中文标题】Spring 和 Hibernate3 的 @Embeddable 问题

【英文标题】：@Embeddable Issue with Spring and Hibernate3

【发布时间】：2013-06-01 06:46:40

【问题描述】：

我在映射我的实体以使用 @Embeddable 类作为连接类代表来实现多对多连接表时遇到问题。基本上这是我想要实现的目标：

我按照 Java Hibernate Persistence 书中给出的教程进行操作，但仍然收到来自这些方法的错误：

org.hibernate.AnnotationException：使用@OneToMany 或@ManyToMany 以未映射的类为目标：nz.co.doltech.ims.project.server.entities.CategoryEntity.incidentCategoryJoins[nz.co.doltech.ims.project.server .entities.IncidentCategoryJoin] 在 org.hibernate.cfg.annotations.CollectionBinder.bindManyToManySecondPass(CollectionBinder.java:1185) 在 org.hibernate.cfg.annotations.CollectionBinder.bindStarToManySecondPass(CollectionBinder.java:710) 在 org.hibernate.cfg.annotations.CollectionBinder$1.secondPass(CollectionBinder.java:645) 在 org.hibernate.cfg.CollectionSecondPass.doSecondPass(CollectionSecondPass.java:65) 在 org.hibernate.cfg.Configuration.originalSecondPassCompile（Configuration.java:1716） 在 org.hibernate.cfg.Configuration.secondPassCompile(Configuration.java:1423) 在 org.hibernate.cfg.Configuration.buildMappings(Configuration.java:1375) 在 org.springframework.orm.hibernate3.LocalSessionFactoryBean.buildSessionFactory(LocalSessionFactoryBean.java:720) 在 org.springframework.orm.hibernate3.AbstractSessionFactoryBean.afterPropertiesSet(AbstractSessionFactoryBean.java:188) 在 org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1541) 在 org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1479)

我正在使用 spring 设置休眠：

org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean

Spring Appcontext.xml：

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop"
       xmlns:context="http://www.springframework.org/schema/context" xmlns:tx="http://www.springframework.org/schema/tx"
       xsi:schemaLocation="
            http://www.springframework.org/schema/beans 
            http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
            http://www.springframework.org/schema/tx
            http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
            http://www.springframework.org/schema/aop 
            http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
            http://www.springframework.org/schema/context
            http://www.springframework.org/schema/context/spring-context-3.0.xsd">

  <tx:annotation-driven transaction-manager="transactionManager" />
  <context:annotation-config />
  <context:component-scan base-package="nz.co.doltech.ims" />
  <aop:aspectj-autoproxy />

  <!-- Configurer that replaces $... placeholders with values from a properties file -->
  <bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
    <property name="locations">
      <list>
         <value>classpath:nz/co/doltech/ims/paths.properties</value>
         <value>classpath:nz/co/doltech/ims/project/project.properties</value>
         <value>classpath:nz/co/doltech/ims/framework/framework.properties</value>
      </list>
    </property>
    <property name="ignoreResourceNotFound" value="no"/>
  </bean>

  <!-- Hibernate Data Source -->
  <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
    <property name="driverClassName" value="$project.database.driver" />
    <property name="url" value="$project.database.url" />
    <property name="username" value="$project.database.user" />
    <property name="password" value="$project.database.password" />
  </bean>

  <!-- Hibernate SessionFactory -->
  <bean id="sessionFactory" class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean"><!-- depends-on="flyway" -->
    <!-- property name="configurationClass" value="org.hibernate.cfg.AnnotationConfiguration" /-->
    <property name="dataSource">
      <ref bean="dataSource" />
    </property>
    <property name="packagesToScan">
      <list>
        <value>$paths.project.server.entities</value>
      </list>
    </property>
    <property name="hibernateProperties">
      <props>
        <prop key="hibernate.dialect">$project.hibernate.dialect</prop>
        <prop key="hibernate.show_sql">$project.hibernate.show_sql</prop>
        <prop key="hibernate.hbm2ddl.auto">$project.hibernate.hbm2ddl</prop>
        <prop key="javax.persistence.validation.mode">none</prop>
      </props>
    </property>
  </bean>

  <!-- Transaction manager for a single Hibernate SessionFactory (alternative to JTA) -->
  <bean id="transactionManager" class="org.springframework.orm.hibernate3.HibernateTransactionManager">
    <property name="sessionFactory" ref="sessionFactory" />
  </bean>

  <bean id="hibernateTemplate" class="org.springframework.orm.hibernate3.HibernateTemplate">
    <property name="sessionFactory" ref="sessionFactory" />
  </bean>

</beans>

这是我带注释的实体类

CategoryEntity.java：

@javax.persistence.Entity
@Table(name = "categories")
public class CategoryEntity implements Entity 

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(unique = true, nullable = false)
    private int id = Entity.UNSAVED_ID;

    @Basic(optional = false)
    @Column(nullable = false, length = 128)
    private String name;

    @Basic(optional = false)
    @Column(nullable = false, length = 512)
    private String description;

    @OneToMany(mappedBy = "category")
    private Set<IncidentCategoryJoin> incidentCategoryJoins;

    @JoinTable(
        name = "category_categorytype",
        joinColumns = @JoinColumn(name = "category_id")
    )
    private Set<CategoryTypeJoin> categoryTypeJoins;

    // id column
    @Override
    public int getId() 
        return this.id;
    
    public void setId(int id) 
        this.id = id;
    

    // name column
    public String getName() 
        return this.name;
    
    public void setName(String name) 
        this.name = name;
    

    // description column
    public String getDescription() 
        return this.description;
    
    public void setDescription(String description) 
        this.description = description;
    

    // incident join columns
    public Set<IncidentCategoryJoin> getIncidentCategoryJoins() 
        return incidentCategoryJoins;
    
    public void setIncidentCategoryJoins(Set<IncidentCategoryJoin> 
        incidentCategoryJoins) 
        this.incidentCategoryJoins = incidentCategoryJoins;
    

    // category type join columns
    public Set<CategoryTypeJoin> getCategoryTypeJoins() 
        return categoryTypeJoins;
    
    public void setCategoryTypeJoins(Set<CategoryTypeJoin> categoryTypeJoins) 
        this.categoryTypeJoins = categoryTypeJoins;
    

IncidentsEntity.java：

@javax.persistence.Entity(name = "incidents")
public class IncidentEntity implements Entity 

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(unique = true, nullable = false)
    private int id = Entity.UNSAVED_ID;

    @Basic
    private String owner;

    @Column(length = 256)
    private String description;

    @Column(name="creation_date")
    private String creationDate;

    @Column(length = 128)
    private String title;

    @Column(length = 20)
    private String date;

    @Column(name="location_details", length = 512)
    private String locationDetails;

    @Column(name="authorities_involved", length = 512)
    private String authInvolved;

    private int status;
    private int state;

    @Column(name="sub_state")
    private int subState;

    @Column(name="reported_by")
    private int reportedBy;

    @JoinTable(
        name = "incident_category",
        joinColumns = @JoinColumn(name = "incident_id")
    )
    @Embedded
    private Set<IncidentCategoryJoin> incidentCategoryJoins;

    // id column
    @Override
    public int getId() 
        return this.id;
    
    public void setId(int id) 
        this.id = id;
    

    // description column
    public String getDescription() 
        return this.description;
    
    public void setDescription(String description) 
        this.description = description;
    

    // owner column
    public String getOwner() 
        return this.owner;
    
    public void setOwner(String owner) 
        this.owner = owner;
    

    // creation date column
    public String getCreationDate() 
        return this.creationDate;
    
    public void setCreationDate(String creationDate) 
        this.creationDate = creationDate;
    

    // title column
    public String getTitle() 
        return this.title;
    
    public void setTitle(String title) 
        this.title = title;
    

    // date column
    public String getDate() 
        return this.date;
    
    public void setDate(String date) 
        this.date = date;
    

    // location details column
    public String getLocationDetails() 
        return locationDetails;
    
    public void setLocationDetails(String locationDetails) 
        this.locationDetails = locationDetails;
    

    // authorities involved column
    public String getAuthInvolved() 
        return authInvolved;
    
    public void setAuthInvolved(String authInvolved) 
        this.authInvolved = authInvolved;
    

    // status column
    public int getStatus() 
        return status;
    
    public void setStatus(int status) 
        this.status = status;
    

    // state column
    public int getState() 
        return state;
    
    public void setState(int state) 
        this.state = state;
    

    // sub state column
    public int getSubState() 
        return subState;
    
    public void setSubState(int subState) 
        this.subState = subState;
    

    // reported by column
    public int getReportedBy() 
        return reportedBy;
    
    public void setReportedBy(int reportedBy) 
        this.reportedBy = reportedBy;
    

    // categories join columns
    public Set<IncidentCategoryJoin> getIncidentCategoryJoins() 
        return incidentCategoryJoins;
    
    public void getIncidentCategoryJoins(Set<IncidentCategoryJoin> 
        incidentCategoryJoins) 
        this.incidentCategoryJoins = incidentCategoryJoins;
    

CategoryTypeEntity.java：

@javax.persistence.Entity
@Table(name = "categorytypes")
public class CategoryTypeEntity implements Entity 
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private int id = Entity.UNSAVED_ID;

    @Basic(optional = false)
    @Column(nullable = false, length = 128)
    private String name;

    @Basic(optional = false)
    @Column(nullable = false, length = 512)
    private String description;

    @OneToMany(mappedBy = "categoryType")
    private Set<CategoryTypeJoin> categoryTypeJoins;

    @OneToMany(mappedBy = "categoryType")
    private Set<IncidentCategoryJoin> incidentCategoryJoins;

    @Override
    public int getId() 
        return this.id;
    
    public void setId(int id) 
        this.id = id;
    

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

    public String getDescription() 
        return this.description;
    
    public void setDescription(String description) 
        this.description = description;
    

    public Set<CategoryTypeJoin> getCategoryTypeJoins() 
        return categoryTypeJoins;
    
    public void setCategoryTypeJoins(Set<CategoryTypeJoin>
        categoryTypeJoins) 
        this.categoryTypeJoins = categoryTypeJoins;
    

所以我将这些表与@Embeddable 注释连接起来，以便hibernate 可以将其映射到实体中。但正如您在错误消息中看到的那样，它根本不是映射。

IncidentCategoryJoin.java：

@Embeddable
public class IncidentCategoryJoin implements Serializable 

    @Parent // Optional back-pointer
    private IncidentEntity incident;

    @ManyToOne
    @JoinColumn(name="category_id",
        insertable = false,
        updatable = false)
    private CategoryEntity category;

    @ManyToOne
    @JoinColumn(name="categorytype_id",
        insertable = false,
        updatable = false)
    private CategoryTypeEntity categoryType;

    public IncidentCategoryJoin() 

    public IncidentCategoryJoin(
            IncidentEntity incident,
            CategoryEntity category,
            CategoryTypeEntity categoryType) 
        // Set fields
        this.incident = incident;
        this.category = category;
        this.categoryType = categoryType;

        // Guarantee referential integrity
        incident.getIncidentCategoryJoins().add(this);
        category.getIncidentCategoryJoins().add(this);
    

    public IncidentEntity getIncident() 
        return incident;
    
    public void setIncident(IncidentEntity incident) 
        this.incident = incident;
    

    public CategoryEntity getCategory() 
        return category;
    
    public void setCategory(CategoryEntity category) 
        this.category = category;
    

    public CategoryTypeEntity getCategoryType() 
        return categoryType;
    
    public void setCategoryType(CategoryTypeEntity categoryType) 
        this.categoryType = categoryType;
    

    public boolean equals(Object o) 
        if (o != null && o instanceof IncidentCategoryJoin) 
            IncidentCategoryJoin that = (IncidentCategoryJoin)o;
            return this.category.equals(that.getCategory()) &&
                this.incident.equals(that.getIncident()) &&
                this.categoryType.equals(that.getCategoryType());
         else 
            return false;
        
    

    public int hashCode() 
        return category.getId() + incident.getId() + categoryType.getId();
    

CategoryTypeJoin.java：

@Embeddable
public class CategoryTypeJoin implements Serializable 

    @Parent // Optional back-pointer
    private CategoryEntity category;

    @ManyToOne
    @JoinColumn(name="categorytype_id",
        insertable = false,
        updatable = false)
    private CategoryTypeEntity categoryType;

    public CategoryTypeJoin() 

    public CategoryTypeJoin(
            CategoryEntity category,
            CategoryTypeEntity categoryType) 
        // Set fields
        this.category = category;
        this.categoryType = categoryType;

        // Guarantee referential integrity
        category.getCategoryTypeJoins().add(this);
        categoryType.getCategoryTypeJoins().add(this);
    

    public CategoryEntity getCategory() 
        return category;
    
    public void setCategory(CategoryEntity category) 
        this.category = category;
    

    public CategoryTypeEntity getCategoryType() 
        return categoryType;
    
    public void setCategoryType(CategoryTypeEntity categoryType) 
        this.categoryType = categoryType;
    

    public boolean equals(Object o) 
        if (o != null && o instanceof IncidentCategoryJoin) 
            IncidentCategoryJoin that = (IncidentCategoryJoin)o;
            return this.category.equals(that.getCategory()) &&
                this.categoryType.equals(that.getCategoryType());
         else 
            return false;
        
    

    public int hashCode() 
        return category.getId() + categoryType.getId();
    

有没有人知道为什么这对我不起作用？请记住，我已经遵循官方 Java Hibernate Persistence 书中的这种方法，所以理论上它对我来说应该可以正常工作。我一直在考虑 Spring 或 hibernate 中存在错误的可能性。无论如何，如果我能在这里得到任何帮助，我将不胜感激。

干杯， 本多尔

【参考方案1】：

呃，不，这不是映射了多少对多的关联。不应将连接表映射为实体。你应该只有三个实体：

事件 类别 CategoryType

连接表只能用于映射多对多关联，在official documentation 中有描述。

【讨论】：

这里的连接类不是实体，它们被映射为可嵌入类以在实体映射中使用。此方法直接取自高级实体关联映射下的Java Persistence With Hibernate（表示带有附加列的链接表的实体类 - 我很快就会在这里需要它）。

如果连接表有额外的列，那么它们应该被映射为实体（而不是作为可嵌入类），并且您应该删除多对多关联并改为与连接实体具有 OneToMany 关联。

我明白了，我会调查一下。除了获得正确的加入之外，这种方法是否有任何理由对我不起作用？ （除了这不是正确的做法之外）。 @Embeddable 注释似乎根本没有在这里映射。

关联只能存在于实体之间。规范未定义和支持与可嵌入的关联。

为 JB 的澄清干杯，现在将进一步推进:)