问题解决了。
DetachedCriteria query=DetachedCriteria.forClass(Comment.class,"c").createAlias("article","a").add(Restrictions.eq("a.id",new Long(article_id)));
这样写就可以了
DetachedCriteria query=DetachedCriteria.forClass(Comment.class,"c").createAlias("article","a").add(Restrictions.eq("a.id",new Long(article_id)));
这样写就可以了
DetachedCriteria query=DetachedCriteria.forClass(Comment.class)
.add(Restrictions.eq("article.id",article_id));