Java 休眠多对多集合筛选

我有以下POJO，里面有一套：

class Word {
    private Long id;
    private String word;
    private int type = WordListFactory.TYPE_DEFAULT;

    private Set<Word> refs = new HashSet<Word>();
...
}

在获取数据的代码中，我启用了过滤器并设置了参数。根据日志，hibernate似乎忽略了这个特定的过滤器，因为它在生成的SQL查询中没有任何条件

• 在条件中使用附加条件

    Word result = null;
  
  session.beginTransaction();
  
  Criteria crit = session.createCriteria(Word.class);       
  
  crit.add(Restrictions.like("word", key))
       .createAlias("refs", "r")
       .add(Restrictions.eq("r.type", getType()));//added alias and restriction for type
  
   List list = crit.list();
  
   if(!list.isEmpty())
       result = list.get(0);   
  
   session.getTransaction().commit();

现在，生成的SQL似乎还可以

   select
        this_.id as id0_1_,
        this_.word as word0_1_,
        this_.type as type0_1_,
        refs3_.word_id as word1_,
        r1_.id as word2_,
        r1_.id as id0_0_,
        r1_.word as word0_0_,
        r1_.type as type0_0_ 
    from
        word this_ 
    inner join
        word_key refs3_ 
            on this_.id=refs3_.word_id 
    inner join
        word r1_ 
            on refs3_.word_ref_id=r1_.id 
    where
        this_.word like ? 
        and r1_.type=?

但是在这个查询之后，有另一个查询获取所有项目

 select
        refs0_.word_id as word1_1_,
        refs0_.word_ref_id as word2_1_,
        word1_.id as id0_0_,
        word1_.word as word0_0_,
        word1_.type as type0_0_ 
    from
        word_key refs0_ 
    left outer join
        word word1_ 
            on refs0_.word_ref_id=word1_.id 
    where
        refs0_.word_id=?

---

也许我做错了什么？

从您给定的代码片段中可以看出以下几点：

• 在多对多关系的情况下，需要3个表、两个实体表和一个联接表。但由于您使用的是相同的实体字，我认为给定的表结构和映射似乎很好
• 尝试使用HQL并指定“LEFT JOIN FETCH”来指定需要在初始sql SELECT中检索哪些关联

查看此链接相关的多对多关系，但他们使用了查询条件

---

So HQL-join-like session.createQuery（“从Word作为w-join获取w.refs作为r，其中w.Word-like:ww和r.type=：tt”）.setString（“ww”，key）.setInteger（“tt”，getType（））.uniqueResult（）；真的很有帮助。限制和过滤器为什么不能正确工作，这仍然是个谜。不管怎样，谢谢你的提示。

   select
        this_.id as id0_1_,
        this_.word as word0_1_,
        this_.type as type0_1_,
        refs3_.word_id as word1_,
        r1_.id as word2_,
        r1_.id as id0_0_,
        r1_.word as word0_0_,
        r1_.type as type0_0_ 
    from
        word this_ 
    inner join
        word_key refs3_ 
            on this_.id=refs3_.word_id 
    inner join
        word r1_ 
            on refs3_.word_ref_id=r1_.id 
    where
        this_.word like ? 
        and r1_.type=?

 select
        refs0_.word_id as word1_1_,
        refs0_.word_ref_id as word2_1_,
        word1_.id as id0_0_,
        word1_.word as word0_0_,
        word1_.type as type0_0_ 
    from
        word_key refs0_ 
    left outer join
        word word1_ 
            on refs0_.word_ref_id=word1_.id 
    where
        refs0_.word_id=?