In My Spring Boot application, I would like to audit DTOs instead of entities and move audit logic to common library which will have #EnableAudit annotation to audit DTO at method level. If I am using JaversBuilder.javers().build(); in common library I would not be able to commit data as it would not know anything of datasource.
I want to create Javers instance in my application and pass datasource to it and then pass Javers instances to common library to perform commit. Is there anyway in Spring boot application to create Javers instance and associat datasource to it which will be used at the time of commit ?
If you take javers-spring-boot-starter, you will get a Javers instance created as a Spring bean. It will be connected to your database and ready-to-use. See https://javers.org/documentation/spring-boot-integration/
Related
How can I test my DAO layer in Spring Boot Application if my application only selects information from database and doesn't write anything?
Even more, my application selects data from view.
The common approach is to write some testing data by method with annotation #BeforeEach and to delete them by method with annotation #AfterEach.
But because my application performs query to view, I can't insert any data in database.
Is there any opportunity to test my DAO layer?
You have a few options:
Use an embedded H2 database then seed it with a data.sql, which you can dump from your test database.
Use DBUnit and define your data in an xml file.
For you I think data.sql is the way to go. Just add a data.sql to your test/resources file and it will be picked up by JPA.
We have a project which is using Spring data with hibernate as ORM.
Now we are introducing new feature for which we want to use Mybatis and eventually replace hibernate with Mybatis in all of the project but in the meanwhile can Mybatis and Hibernate live together for sometime until we make total switch. I am particularly concerned with Mybatis and Hibernate will share connection pool i.e. Hikari CP (default connection pooling that comes with spring boot, yes this project is Spring boot project!). I am not 100% sure that data source will be shared between both of them? So the question is how feasible is to have Mybatis and Hibernate together for some time ?
Honestly I never tested them together - yes both of them on its own plus JDBC, and everything worked properly - but, at first glance, there is no reason why Spring Data JPA with Hibernate and Mybatis cannot share the same connection pool and data source.
First, both frameworks can access and autodetect the same data source and underlying connection pool.
According to your comments, you are probably using Mybatis-Spring-Boot-Starter. This starter will provide you the ability to autodetect the configured data source and register a properly configured SqlSessionFactory with it.
A similar behavior of course is applicable for Spring Data JPA as well.
Moreover neither Mybatis nor Spring Data JPA should impose any restriction - number of connections, etcetera - on the underlying connection pool.
Finally, Spring Data JPA and Mybatis, this last one with the help of the companion library mybatis-spring, both support Spring's annotation-driven transaction management capability, you only need to properly define your #Transactional annotations in your methods.
Despite my recommendation would be, if possible, not to mix in the same service methods your Spring Data repositories and Mybatis mappers, I think there is no reason not to.
Spring Data Hibernate and Mybatis will be able to share the same connection pool, data source, and transaction manager.
However, there are some situations to watch out for, e.g. avoid manipulating the same object loaded by Hibernate with Mybatis.
Account account = AccountRepository.findById( 999 );
account.setAmount(111);
account.setCode(111);
// May use account to read with Mybatis
// But avoid manipulating account with Mybatis
AccountRepository.save( account );
You can get the JDBC connection from a MyBatis session using getConnection() and use it to build an Hibernate session :
sessionFactory.withOptions().connection(connection).openSession();
You can also get a reference to the underlying connection of an Hibernate Session using the doWork method:
session.doWork(new Work() {
#Override
public void execute(Connection connection) throws SQLException {
When using spring-data-jpa with hibernate as jpa provider, are the Object/Entity lifecycles same as when using hibernate directly or as defined by hibernate (or might be jpa spec itself).
Hibernate defines these lifecycles to entities - Transient, Persistent, Detached, Removed.
Are these same life cycles applicable when using spring-data-jpa too.
If so how does below the methods provided by Hibernate map with the methods of spring jpa crud repository.
//below methods in hibernate move an entity to persistent state
save(e),
persist(e);
update(e);
saveOrUpdate(e);
lock(e);
merge(e);
and
//below methods in hibernate move an entity to detached state
detach(e);
evict(e);
For the first part of the question:
Spring Data JPA just offers some comfortable mechanics on top of JPA.
The persistence, mapping and life cycle is still managed by JPA or its implementation, i.e. Hibernate in your case.
This means the life cycle is the same.
As for the mapping between Spring Data JPAs methods and Hibernates/JPA methods see the following table.
Spring Data
JPA
CrudRepository.save*
for new entities EntityManager.persist, EntityManager.merge otherwise
CrudRepository.delete*
EntityManager.remove
CrudRepository.findById
EntityManager.find*
JpaRepository.*flush
EntityManager.flush
JpaRepository.getById
EntityManager.getReference
Other query methods predefined in interfaces or otherwise use various types of queries.
Spring Data Jpa is only an abstraction layer and not provide a lifecycle management. Therefore, if you are using hibernate as a jpa implementation your object's lifecycle will regulated according to hibernate's lifecycle management.
Also, you can find some other explanations here and here as well.
I'm studying Spring boot, and i have create several entity, my problem now is to retrieve the data from controller to save it on db.
Surfing on the web I have learned that i have to use JPARepositery or CrudRepositery in this way:
An example with User entity
public interface UserRepository extends CrudRepository<User, Integer> {
}
and to save
User user = new User();
userRepository.save(user);
But if I have many entities, Do I need to create a repository for each entity?
I have read about Session, FactorySession and Transaction they are compatible with Spring boot? How it works? and #Transactional tag how it works?
Thanks in advance
Yes, usually you need to create one Repository per Entity. This is also a good practice because you are placing operations and queries related to the same Entity in the same Repository.
Yes, you can obtain a Session and a FactorySession object (Hibernate), but I would advice you against using Hibernate directy. Instead, it is better to use Spring Data or JPA mechanisms to access your database (just as you do using a Repository). The reason is because Hibernate is an implementation of the JPA standard and today we use JPA to access databases (because it masks the exact implementation of the ORM). This way you can later (potentially) replace Hibernate with another JPA implementation (such as EclipseLink) without the need to change your code (in theory). In most projects you will find Hibernate being used, however.
Yes, Transaction is a Spring annotation and an important database transaction mechanism in Spring Boot, too.
Is there listeners available in javers which will be invoked before executing a specific operation.
For example, a method like preUpdate() which will be invoked before registering an update operation.
I am using javers with Mongo DB and Spring
PS: Looking for feature similar to conditional auditing in Hibernate Envers
There is no such feature in JaVers and no plans for adding it. You can implement these hooks in standard Spring AOP, for example by providing your implementation of JaversAuditableAspect.