hibernate - Grails:域类映射( hibernate 用户类型的集合)

Question

我想知道是否可以实现以下域模型。

让我们有一个域类，其中包含一组间隔(joda 时间)。我可以使用 org.joda.time.contrib.hibernate.PersistentInterval hibernate 用户类型将 Interval 映射到数据库表(通过与 http://www.grails.org/JodaTime+Plugin 类似的方式)。但是，如果我有一组间隔，而不仅仅是一个间隔，我就无法弄清楚如何实现映射。

例子:

class Activity {  
   ...    
   Set intervals = []  
   ...  
   static hasMany = [    
       intervals: org.joda.time.Interval  
   ]  

   // This is incorrect implementation, I have set of intervals  
   // and this would be correct if I had only one interval  
   // How to implement mapping in this case?  
   static mapping = {  
       intervals type: PersistentInterval, {  
           column name: "start"  
           column name: "end"  
       }  
   }  

}

上面的实现失败并出现以下错误:

2010-10-23 18:30:25,483 [main] ERROR context.GrailsContextLoader - Error executing bootstraps: Error creating bean with name 'messageSource': Initialization of bean failed; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'transactionManager': Cannot resolve reference to bean 'sessionFactory' while setting bean property 'sessionFactory'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sessionFactory': Invocation of init method failed; nested exception is org.hibernate.MappingException: Foreign key (FK4FDC5B1E5107CA0:activity_intervals [start,end])) must have same number of columns as the referenced primary key (activity [id]) org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'messageSource': Initialization of bean failed; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'transactionManager': Cannot resolve reference to bean 'sessionFactory' while setting bean property 'sessionFactory'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sessionFactory': Invocation of init method failed; nested exception is org.hibernate.MappingException: Foreign key (FK4FDC5B1E5107CA0:activity_intervals [start,end])) must have same number of columns as the referenced primary key (activity [id]) at org.grails.tomcat.TomcatServer.start(TomcatServer.groovy:212)

我认为解决此问题的方法是提取 Interval 以分离扩展 Interval 的域类并在其中指定映射。但是，Interval 是最终类，因此无法扩展。

谢谢你的建议。

Answer 1

我正在回答我自己的问题，也许这个答案对某人有用。

到目前为止，我只找到了一种实现给定模型的方法 - 来自 Hibernate XML mapping files :

<hibernate-mapping package="mappingtest">  
    <class name="Activity">  
        <id name="id">  
            <generator class="native"/>  
        </id>  
        <set name="intervals">  
            <key column="activity_id" not-null="true"/>  
            <element type="org.joda.time.contrib.hibernate.PersistentInterval">  
                <column name="startDate"/>  
                <column name="endDate"/>  
            </element>  
        </set>  
    </class>  
</hibernate-mapping>  

和域类实现:

class Activity {    
    Long id    
    Set intervals = []

    static constraints = {
    }
}

我还必须将域类从 grails-app/domain 移动到 src/groovy 目录，否则应用程序运行失败(grails-1.3.5):

...
org.hibernate.DuplicateMappingException: Duplicate class/entity mapping mappingtest.Activity
...

我发现上述实现的第二个问题是，当我通过以下方式打开脚手架(用于测试目的)时:

class ActivityController {
    static scaffold = true
    ...
}

显示创建的事件失败并出现错误:

Exception Message: No such property: id for class: org.joda.time.Interval Possible solutions: end Caused by: Error evaluating expression [i.id] on line [38]: No such property: id for class: org.joda.time.Interval Possible solutions: end

但是手动实现从 DB 获取事件及其显示工作。

编辑:另外我找到了脚手架和 DuplicateMappingException 问题的解决方案。它们是由 Activity.hbm.xml 的无效位置引起的 - 缺少包目录结构。正确的位置是 grails-app/conf/hibernate/mappingtest/Activity.hbm.xml。