java - Hibernate:使用集合条件(HashSet)

Question

我有以下类(class):

  public class Folder{
      private Set<Documents> documents;
      private Set<Clip> clips;
  }

  public class Clip{
      private Owner owner;
  }

我需要在黄色文件夹中找到不错文档的列表，这些文件夹有所有者 文件夹中的剪辑，其名称类似于搜索字符串。像这样的东西(不工作):

Criteria criteria = session.createCriteria(Document.class);

criteria.add(Restrictions.eq("isNice", 1));
criteria.createCriteria("folder").add(Restrictions.eq("isYellow", 1));
criteria.createCriteria("clips");
criteria.createCriteria("owner").add(Restrictions.like("name", search));

List documents = criteria.list();

如何为 HashSet 创建条件？或者

• 也许我应该使用 hql 查询
• 也许我可以只编辑 List documents , 删除不良条目？
• 是否有可能使用标准？
• 如果不是，还有什么办法？

编辑。我找到了这段代码:

    List cats = sess.createCriteria(Cat.class)
    .createCriteria("kittens", "kt")
        .add( Restrictions.eq("name", "F%") )
    .setResultTransformer(Criteria.ALIAS_TO_ENTITY_MAP)
    .list();
Iterator iter = cats.iterator();
while ( iter.hasNext() ) {
    Map map = (Map) iter.next();
    Cat cat = (Cat) map.get(Criteria.ROOT_ALIAS);
    Cat kitten = (Cat) map.get("kt");
}

但我不明白它到底做了什么。什么是 resultTransformer？

拜托，任何建议或提示都会有很大帮助!谢谢!

Answer 1

Criteria criteria = session.createCriteria(Document.class, "document");
criteria.add(Restrictions.eq("document.nice", true));
criteria.createAlias("document.folder", "folder");
criteria.add(Restrictions.eq("folder.yellow", true));
criteria.add(Subqueries.exists(clipOwnerWithNameInFolder(name, "folder"));

private DetachedCriteria clipOwnerWithName(String searchedName, String aliasOfFolder) {
    DetachedCriteria c = DetachedCriteria.forClass(Clip.class, "clip");
    c.createAlias("clip.owner", "owner");
    c.createAlias("clip.folder", "clipFolder");
    c.add(Restrictions.propertyEq("clipFolder.id", aliasOfFolder + ".id");
    c.add(Restrictions.like("owner.name", searchedName);
    c.setProjection(Projections.id());
}

这需要 Clip/Folder 关联是双向的(即您需要在 Clip 中有一个 folder 字段)。如果不是这种情况，则可以像这样创建分离条件:

private DetachedCriteria clipOwnerWithName(String searchedName, String aliasOfFolder) {
    DetachedCriteria c = DetachedCriteria.forClass(Folder.class, "clipFolder");
    c.createAlias("clipFolder.clips", "clip");
    c.createAlias("clip.owner", "owner");
    c.add(Restrictions.propertyEq("clipFolder.id", aliasOfFolder + ".id");
    c.add(Restrictions.like("owner.name", searchedName);
    c.setProjection(Projections.property("clip.id"));
}