是否可以将内部类映射到targetclass
,如果可能的话,如何完成?我是此@SqlResultSetMapping
功能的新手:
@SqlResultSetMapping(
name = "EventSurveysMapping",
classes = {
@ConstructorResult(
targetClass = Survey.class,
columns = {
@ColumnResult(name = "surveyid", type = Long.class),
})
})
所以targetClass
Survey.class
具有:
public class Survey {
private Long surveyid;
private List<SurveyQuestion> surveyquestions;
// constructor with mapped fields
}
我将如何映射List<SurveyQuestion>
字段?
调查:
public class SurveyQuestion {
private Long surveyquestionid;
private String surveyquestion;
private List<String> surveyanswers;
}
也非常相似。我将如何映射List<String>
?
尝试将映射映射到 List.class
时会得到例外:
@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 描述:对象[是主要ID,它是唯一ID],类别为class [类Java.lang.String],无法转换为[接口 java.util.list]
民意调查:
@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
}
根据我的经验,当我不得不绘制一件事情时,我终于做了这样的事情:
@OneToMany
private Set<SurveyQuestion> surveyanswers;
如果您使用的是JPA提供商支持基本类型集合的所有这些。(例如Hibernate具有@CollectionFolements注释(。