What are some examples of using JPA Criteria API?

Can you provide some examples of using the JPA Criteria API?

Sure! The JPA Criteria API allows you to build queries programmatically. For example, to select all users with a specific age, you can use the CriteriaBuilder to create a query.

How do I create a CriteriaQuery for that?

You would start by creating an instance of CriteriaBuilder, then create a CriteriaQuery object, and finally define the root and predicates for your query.

Can you show me a code snippet for that?

Absolutely! Here's a simple example:

CriteriaBuilder cb = entityManager.getCriteriaBuilder();
CriteriaQuery<User> query = cb.createQuery(User.class);
Root<User> user = query.from(User.class);
query.select(user).where(cb.equal(user.get("age"), 25));
List<User> results = entityManager.createQuery(query).getResultList();

What if I want to add sorting to the results?

You can use the orderBy method of the CriteriaQuery. For example, to sort by name:

query.orderBy(cb.asc(user.get("name")));