使用 JpaRepository 缓存

Question

Hi I have extended a JpaRepository interface in following way.

public interface StudentRepository extends JpaRepository<Student,Integer>
{
@Query(value= "SELECT s.id FROM student as s where s.createdat >  ADDDATE(CURRENT_DATE, :maxage ", nativeQuery = true )
public List<Integer> findWaitingStudentIds(@Param("maxage")int maxAge);
}

Here is the Entity class.

@Entity(name="student ")
public class Student implements Serializable {
    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    @Column(unique=true, nullable=false)
    private Integer  id;
    @Temporal(TemporalType.TIMESTAMP)
    @Column(updatable = false,insertable = false)
    private Date createdat;  
}

I want to add cache for "List findWaitingStudentIds" method. How can I achieve this?

Answer 1

I can copy paste my answer from this StackOverflow question:

How should I implement a cache object/system in Spring?

Spring introduced abstraction for Cache in 3.x RELEASE. You can read about it in official Spring documentation (the site is down today for some reason :)), or at this post for example.

http://dzone.com/articles/spring-cache-abstraction-0

With this abstraction, all you need to do to enable cache is to add some annotations to your services, like

To add value to the cache

@Cacheable("customers") public Customer findCustomer(long customerId) {...}

To remove value to the cache

@CacheEvict(value="customer", allEntries = true) public void removeAllCustomers(long customerId) {...}

Answer 2

You may consider reading the Hibernate Reference Manual . It helped me quite a lot when I used it for the very first time. It really clarify concepts and the way it works.

Some other answers are present in StackOverflow: Hibernate Cache Reference .

Several quick tutorials are also available on the Web:

• Hibernate cache levels tutorial
• Hibernate Caching .
• Hibernate EHCache Second Level Caching Example Tutorial .
• ... .

I hope al this info helps you.