JPA 2.1 @SqlResultSetMapping绑定内部类到目标类

Question

是否有可能将内部类映射到targetclass，如果可能的话，它是如何完成的？我是新来这个@SqlResultSetMapping功能：

@SqlResultSetMapping(
     name = "EventSurveysMapping", 
     classes = { 
       @ConstructorResult(
         targetClass = Survey.class, 
         columns = { 
           @ColumnResult(name = "surveyid", type = Long.class), 
         }) 
     }) 

所以targetClassSurvey.class有：

public class Survey { 
    private Long surveyid; 
    private List<SurveyQuestion> surveyquestions; 
// constructor with mapped fields 
} 

我怎么会映射List<SurveyQuestion>场？

SurveyQuestion：

public class SurveyQuestion { 
    private Long surveyquestionid; 
    private String surveyquestion; 
    private List<String> surveyanswers; 
} 

而且，和非常相似。我将如何映射List<String>？

我想什么时候做映射List.class得到一个例外：

@SqlResultSetMapping(
     name = "EventPollsMapping", 
     classes = { 
       @ConstructorResult(
         targetClass = Poll.class, 
         columns = { 
           @ColumnResult(name="pollid", type = Long.class), 
           @ColumnResult(name="questionid", type = Long.class), 
           @ColumnResult(name="pollquestion", type = String.class), 
           @ColumnResult(name="pollanswers", type = List.class) // this mapping is the cause of the exception 
         }) 
     }) 

例外：

org.eclipse.persistence.exceptions.ConversionException异常 说明：对象[它是Primary ID，它是唯一ID]，类 [class java.lang.String]，无法转换为[interface java.util.List]

投票：

@XmlRootElement 
@XmlType (propOrder={"pollid", 
"pollquestionid", 
"pollquestion", 
"pollanswers" 
}) 
public class Poll { 
    private Long pollid; 
    private Long pollquestionid; 
    private String pollquestion; 
    private List<String> pollanswers; 


    public Poll(){} 

    public Poll(Long pollid, Long pollquestionid, String pollquestion, List<String> pollanswers) { 
     super(); 
     this.pollid = pollid; 
     this.pollquestionid = pollquestionid; 
     this.pollquestion = pollquestion; 
     this.pollanswers = pollanswers; 
    } 

// setters & getters 
} 

Answer 1

以我的经验，当我不得不映射的事物的集合，最后我做了这样的事情：

@OneToMany 
private Set<SurveyQuestion> surveyanswers; 

所有这一切，如果你是使用支持基本类型集合的JPA提供程序的扩展。 （例如Hibernate有@CollectionOfElements注解）。