使用hibernate进行类强制转换异常

Question

我只是想检索数据列表，但是使用下面的代码为什么我会得到类转换异常......

public List<TbDiscussionForumAnswere> findTbDiscussionForumAnswerebyforumQuestionId(Integer forumQuestionId) {
session = sessionFactory.getCurrentSession();
TbDiscussionForumAnswere TbDiscussionForumAnswere = (TbDiscussionForumAnswere)session.createCriteria(TbDiscussionForumAnswere.class)                .add(Restrictions.eq("forumQuestionId.forumQuestionId", forumQuestionId));
return (List<TbDiscussionForumAnswere>) TbDiscussionForumAnswere.getTbDiscussionForumAnswereCollection();
}

上面的方法给我以下异常

java.lang.ClassCastException: org.hibernate.internal.CriteriaImpl cannot be cast to com.medikm.entity.TbDiscussionForumAnswere

谢谢你

Answer 1

您正在创建Criteria对象而不是TbDiscussionForumAnswere对象。这是一个正确的错误消息。 您使用此Criteria类来执行查询。你应该把它投到Criteria类

Answer 2

session.createCriteria(TbDiscussionForumAnswere.class).add(Restrictions.eq("forumQuestionId.forumQuestionId", forumQuestionId));返回Critera not和object TbDiscussionForumAnswere

因此您必须将行更改为：

Critera critera  = (Critera)session.createCriteria(TbDiscussionForumAnswere.class).add(Restrictions.eq("forumQuestionId.forumQuestionId", forumQuestionId));

Answer 3

在我使用的代码下面，这对我来说很好，谢谢大家的答案

List<TbDiscussionForumAnswere> tbDiscussionForumAnswereList = session.createCriteria(TbDiscussionForumAnswere.class)
.add(Restrictions.eq("forumQuestionId.forumQuestionId",forumQuestionId))
.setFetchMode("forumQuestionId", FetchMode.LAZY)
.list();