Criteria Api是Hibernate的一个很好的概念。根据我的观点，这些是我们可以区分HQL和Criteria Api的少数点

HQL is to perform both select and non-select operations on the data, but Criteria is only for selecting the data, we cannot perform non-select operations using criteria. HQL is suitable for executing Static Queries, where as Criteria is suitable for executing Dynamic Queries HQL doesn’t support pagination concept, but we can achieve pagination with Criteria. Criteria used to take more time to execute than HQL. With Criteria we are safe with SQL Injection because of its dynamic query generation but in HQL as your queries are either fixed or parametrized, there is no safe from SQL Injection

对于动态条件查询，我们可以根据我们的输入构造查询..在Hql查询是静态查询的情况下，一旦我们构造，我们就不能改变查询的结构。

当我不知道哪些输入将用于哪些数据时，我通常使用Criteria。就像在一个搜索表单上，用户可以输入1到50个项目中的任何一个，我不知道他们会搜索什么。在检查用户正在搜索的内容时，很容易将更多内容添加到条件中。我认为在这种情况下放置HQL查询会更麻烦一些。当我确切地知道我想要什么时，HQL是很棒的。

条件是指定利用第二级查询缓存中的特殊优化的自然键查找的唯一方法。HQL没有任何方法来指定必要的提示。

你可以在这里找到更多信息:

http://tech.puredanger.com/2009/07/10/hibernate-query-cache/

We used mainly Criteria in our application in the beginning but after it was replaced with HQL due to the performance issues. Mainly we are using very complex queries with several joins which leads to multiple queries in Criteria but is very optimized in HQL. The case is that we use just several propeties on specific object and not complete objects. With Criteria the problem was also string concatenation. Let say if you need to display name and surname of the user in HQL it is quite easy (name || ' ' || surname) but in Crteria this is not possible. To overcome this we used ResultTransormers, where there were methods where such concatenation was implemented for needed result. Today we mainly use HQL like this:

String hql = "select " +
            "c.uuid as uuid," +
            "c.name as name," +
            "c.objective as objective," +
            "c.startDate as startDate," +
            "c.endDate as endDate," +
            "c.description as description," +
            "s.status as status," +
            "t.type as type " +
            "from " + Campaign.class.getName() + " c " +
            "left join c.type t " +
            "left join c.status s";

Query query =  hibernateTemplate.getSessionFactory().getCurrentSession().getSession(EntityMode.MAP).createQuery(hql);
query.setResultTransformer(Transformers.ALIAS_TO_ENTITY_MAP);
return query.list();

因此，在本例中，返回的记录是所需属性的映射。

对我来说，Criteria是一个很容易理解的动态查询。但我说到目前为止的缺陷是，它加载所有的多-一等关系，因为我们只有三种类型的FetchModes，即选择，代理和默认，在所有这些情况下，它加载多-一(可能是我错了，如果这样帮助我:))

第二个问题与标准是，它加载完整的对象，即，如果我想只是加载一个员工的EmpName，它不会提出这个，而是提出完整的员工对象，我可以从它得到EmpName，因为这真的工作不好的报告。因为HQL只是加载(没有加载关联/关系)你想要的，所以性能会提高很多倍。

Criteria的一个特点是，它将使你免受SQL注入的伤害，因为它的动态查询生成，而在HQL中，ur的查询要么是固定的，要么是参数化的，因此在SQL注入中不安全。

同样，如果你在你的aspx.cs文件中编写HQL，那么你与你的DAL紧密耦合。

总的来说，我的结论是，有些地方你不能没有HQL，比如报告，所以使用它们，否则Criteria更容易管理。