Java / JPA中类似Django的查询

Question

Is there any library or framework to make JPA queries in a less verbose way such as:

User.query("age < 30")

instead of:

Query query = entityManager.createQuery("select u FROM User u WHERE age < 30");
return query.getResultList();

I suppose there is no standard way to do it with JPA. I've seen Hibernate Criteria API , that is not as simple as Django and forces your application to be coupled to Hibernate. I'd like to know what do you think about it and other approaches.

Answer 1

Yes, a Java framework allow you to do that: Play! framework. It's a framework similar to Django but complety written using Java. http://www.playframework.org/documentation/1.0.1/model

For instance you can write something like:

User.find("age< ?", 30).fetch();

Moreover this is not coupled to hibernate you can use other technologies like Google App Engine datastore or Amazon Simple DB throw Siena

Answer 2

You can make your query shorter:

from User where age < 30

Additionally I would like to add that the Hibernate API is much more powerful and adds things like polymorphism and prefetching in a nice way, so don't give up on it yet.

Answer 3

与此相关，我还发现Spring Roo能够生成遵循此“Active Record Pattern”的实体，并允许开发人员包含finder方法。