在休眠标准中，多个连接结果是重复的

Question

我通过Criteria API获取了多个数据。

我在实体中的关联映射是

public class UserGroupEntity{

    private Set<UserEntity> users = new TreeSet<>();
    private List<DocumentEntity> documents = new ArrayList<>();

    @ManyToMany(fetch=FetchType.LAZY)
    @JoinTable(
        name="FG_DDA_User__UserGroup", 
        joinColumns={@JoinColumn(name="usergroup_id", nullable=false),},       
        inverseJoinColumns={@JoinColumn(name="user_id", nullable=false)})
    public Set<UserEntity> getUsers() {
        return users;
    }

    public void setUsers(Set<UserEntity> users) {
        this.users = users;
    }

    /**
     * @return the documents
     */
    @ManyToMany(fetch=FetchType.LAZY)
    @JoinTable(
        name="FG_DDA_Document__UserGroup", 
        joinColumns={@JoinColumn(name="usergroup_id", nullable=false),}, 
        inverseJoinColumns={@JoinColumn(name="document_id",nullable=false)})
    public List<DocumentEntity> getDocuments() {
        return documents;
    }
}

我从标准中获取数据。代码是

Criterion criterian = Restrictions.idEq(id);
Criteria criteria = getSession().createCriteria(getPersistentClass());
criteria.add(criterian);
if(eagerFetchColumn != null){
    for (String string : eagerFetchColumn) {
        criteria.setFetchMode(string, FetchMode.JOIN);
    }
    criteria.setResultTransformer(Criteria.DISTINCT_ROOT_ENTITY);
}
List<UserGroupEntity> result = (List<UserGroupEntity>)criteria.list();
if (result.size() == 1) {
    return result.iterator().next();
}
if (result.size() == 0) {
    return null;
}
throw new RuntimeException("Found more than one object with the given ID, verify integrity of you data");

我正在获取UserGroupEntity的唯一数据，用户也是唯一的，因为它是Set。但文件是多个，因为它是列表，这是我的问题。我还可以通过列表中的多个加入来接收唯一的文档。

查询：

SELECT t_.id          AS a,
  t_.name             AS b,
  du_.usergroup_id    AS c,
  d_.id               AS d,
  d_.id               AS e,
  d_.activeVersion_id AS f,
  d_.name             AS g,
  uu_.usergroup_id    AS h,
  u_.id               AS i,
  u_.id               AS j,
  u_.name             AS k,
  u_.password         AS l,
  u_.role_id          AS m,
  u_.toc_code         AS n,
  u_.email_id         AS o,
  u_.isValid          AS p
FROM dbo.FG_DDA_UserGroup t_
LEFT OUTER JOIN dbo.FG_DDA_Document__UserGroup du_ ON t_.id=du_.usergroup_id
LEFT OUTER JOIN dbo.FG_DDA_Document d_ ON du_.document_id=d_.id
LEFT OUTER JOIN dbo.FG_DDA_User__UserGroup uu_ ON t_.id=uu_.usergroup_id
LEFT OUTER JOIN dbo.FG_DDA_User u_ ON uu_.user_id=u_.id
WHERE t_.id   = ?