I am using spring data JPA repository, my requirement is when i call repository class methods in service class it should show only custom methods like addUser(X,Y) instead of save().
Few things i understand, implementation of spring repository is provided by spring framework at runtime, So we cannot provide out own implementation. (This will overhead).
All methods in JPARepository is public only, so its obivious when we implement this interface all methods will be visible through out.
I am thinking of using DAO and Repository both at same time. DAO will provide custom function signature and repository will implement DAO interface.
Any Hack ?
If you don't want the methods from JpaRepository or CrudRepository, don't extend those but just Repository instead. It is perfectly fine to have a repository interface like
MyVeryLimitedRepository extends Repository<User, Long> {
User findByName(String name);
}
Of course methods like addUser(X,Y) will need a custom implementation.
You can very well use DAO pattern in this case .
By implementing DAO Pattern in Service Class
You create a wrapper between Service and Repository.
You can custom code your DAO layer to only expose custom methods to service layer
Related
I am trying to implement a Spring Boot REST API but I was asked to use a interface as dependency but no impl, and I don't know how to achieve this. The way I implemented was to have service classes for my entities and there I would just call the repository in my methods. I would like an example of implementation like this.
I watched some youtube tutorials but they all used impl classes
Your controller should have a field of your interface type, with the injecting annotation (in spring it's #Autowired). The DI framework will do the heavy-lifting on startup and inject the correct implementation at runtime
#Controller
public class MyController {
#Autowired
private MyInterface myInterface;
....
}
For this to work, your framework needs to recognize the concrete class. In spring you can achieve this in multiple ways - scanning package paths, xml configuration files and more.
Check the spring documentation to see which way suits you best
In my spring boot project, I am using this starter jpa . i have done all the db related thing in appliction.properties. Project is working fine . I fail to undestand where is this methods defination. We have just defined a abstract method how is this method even working?
public interface UserRepository extends JpaRepository<UserEntity, Integer>{
Optional<UserEntity> getUserByUserName(String user);
}
This is part of the magic of JPA Repositories. I don't actually know the details of how it works either, I just know how to use it.
Ultimately, I think it has to do with how Spring proxies interfaces. Spring will create an instance of an interface at runtime. When the methods are named according to the specs, Spring can generate an appropriate method.
Here is a good article that goes into detail on how you can construct the method names to make the query that you want: https://www.baeldung.com/spring-data-derived-queries.
i am new to spring
in my spring web project DAO and service they created the interface and implementing it created class. can we liminate interface.
The whole point of using interface is to create abstraction. When you call you DAO from Service, your service is not aware of the actual implementation of DAO/ cases in which you have multiple implementations of your DAO interface, your service is not aware of the actual impl being used.
With spring you will use - Autowire to inject the dependency. You will refer your Dependency using interface.
#Component/#Service
class ServiceImpl {
#Autowired
private DAOInterface dao;
// Rest of code
}
Spring knows - to create the instance of this ServiceImpl it needs to inject a concrete impl of DAOInterface type. In case you have concrete implementation, it does so. In case you have multiple impls - you need to define by bean name which implementation you need using #Qualifier.
Interface is kind of a contract for your impl classes. Other than abstracting the actual impl, it helps you decoupling the layers by not directly having a dependency on the concrete classes. This is a good design pattern
Am new to Spring boot, i have seen example where we create repository to perform various operarion with the given Object. here is the sample one
#RepositoryRestResource(collectionResourceRel = "people", path = "people")
public interface PersonRepository extends PagingAndSortingRepository<Person, Long> {
List<Person> findByLastName(#Param("name") String name);
}
so from the rest client if i send People jason
http://localhost:8080/people{ .... }
it inserts to the Database, internally it calls save method.
Here after calling from the REST client , i want to do some validation or business login and then insert to the database, how can i do it? It means i want to call a service method to do all the business logic and then insert so how can i call service method from repository class?
This repository is an interface and will allow you to perform various operations (here operations means DB related operations) involving Person objects. It gets these operations by extending the PagingAndSortingRepositry interface defined in Spring Data Commons.
At runtime, Spring Data REST will create an implementation of this interface automatically. Then it will use the #RepositoryRestResource annotation to direct Spring MVC to create RESTful endpoints at /people.
I don't think your requirements can be fulfilled with having the "#RepositoryRestResource" on the repository. You may want to create a proper sprint-boot application with the api, service and repo layer to perform the tasks you want to perform.
Is it possible to write my own function implementation along usage of spring repositories?
I would like to actually implement the function
getUserByFirstName()
and not get it automagically.
While i still want to get
getUserById()
automagically from spring-data.
1) is it possible?
2) is it possible to achieve logging for all methods spring data automagically generates? (or should i write them manually with
logger.log("entering method ...");
See section 1.3 of the manual for the first requirement:
http://docs.spring.io/spring-data/jpa/docs/1.4.2.RELEASE/reference/html/repositories.html#repositories.single-repository-behaviour
For the second requirement I guess some AOP based solution might work for you well here. See here for example using Spring's AOP support:
logging with AOP in spring?
Yes, you can!!!
There is an amazing feature in Spring data that allows this:
Create an interface with your custom method:
public interface UserRepositoryCustom {
User getUserByFirstName();
}
Make your Spring Data interface extends this new interface, as well as the Spring data crud interface (or JPA, Mongo or whatever spring data interface you're extending):
public interface MySpringDataRepository extends CrudRepository<User, Long>, UserRepositoryCustom {
}
Create a class that implements only your custom interface. The name of the class must be Impl, for instance: UserRepositoryImpl:
public class MySpringDataRepositoryImpl implements UserRepositoryCustom {
public User getUserByFirstName(){
//Your custom implementation
}
}
Now, you only need to inject the Spring data repository in your service and you can use both methods: the spring-data implemented method and your custom implemented method:
#Inject private MySpringDataRepository myRepository;
That's it!!
Look at this section in the documentation:
Spring Data Custom implementations