java 使用 JpaRepository 缓存

Cache with JpaRepository

提问by user1516815

Hi I have extended a JpaRepository interface in following way.

嗨，我以以下方式扩展了 JpaRepository 接口。

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 Entityclass.

这是Entity课堂。

@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?

我想为“List findWaitingStudentIds”方法添加缓存。我怎样才能做到这一点？

回答by mavarazy

I can copy paste my answer from this StackOverflow question:

我可以从这个 StackOverflow 问题中复制粘贴我的答案：

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

我应该如何在 Spring 中实现缓存对象/系统？

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://java.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) {...}

Spring 在 3.x RELEASE 中引入了对 Cache 的抽象。您可以在 Spring 的官方文档中阅读它（该站点今天由于某种原因关闭了 :)），或者例如在这篇文章中。

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

通过这种抽象，启用缓存所需要做的就是向服务添加一些注释，例如

为缓存添加值

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

删除缓存中的值

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

回答by kazbeel

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.

您可以考虑阅读Hibernate 参考手册。当我第一次使用它时，它对我帮助很大。它确实阐明了概念及其工作方式。

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

StackOverflow: Hibernate Cache Reference中提供了其他一些答案。

Several quick tutorials are also available on the Web:

Web 上还提供了几个快速教程：

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

• Hibernate 缓存级别教程
• 休眠缓存。
• Hibernate EHCache 二级缓存示例教程。
• ....

I hope al this info helps you.

我希望所有这些信息对您有所帮助。