I am new to SpringData and I am not getting what is happening here. I have created an Interface that extends PagingAndSortingRepository and overrided the findAll() method like this:
#Override
#Query
List<MyEntity> findAll();
I am calling this method in my service, but it is making my app to throw an exception Caused by: java.lang.StackOverflowError because that method is reading through the entire database, not only from MyEntitytable in database. Any idea?
Apparently the problem is in the configuration of EclipseLink. In persistence.xml I added this row <shared-cache-mode>NONE</shared-cache-mode> and now it works as it should.
no need to override getall() method.in your service autowired that dao or repository class and using this you can directly call the findall() method.
in the case you want to write your custom method apart from what given by spring data jpa then we use the #Query to write custom query.
No Need to Override. What i have done is i have created a repository i.e
FavoriteRepository which is extending JpaRepository and i have mentioned the
dbmodel name (Favorite)
like this JpaRepository<Favorite, Long> // Here Favorite is my model name
and Long is the type of primary key mentioned in db model Favorite as #Id
#Repository
public interface FavoriteRepository extends JpaRepository<Favorite, Long>{
}
Now you can use method findOne or findAll. As these methods are present in
Jparepository.Hope so it will help
If you want to add new method then use #Query with JpQL
#Query(value = "select f from Favorite f where f.userId=:userId ")
public List<Favorite> getFavoritesForUser(#Param("userId") String userId);
Related
In a Spring Boot application using a #Repository with derived queries is somewhat easy.
#Repository
public interface UserRepository extends JpaRepository<User, Long> {
Optional<User> findByEmail(String email);
}
If, however, the queries are getting more complex (joins, subqueries, etc.) then we're using Querydsl like in the following pseudo-code example.
JPAQuery<User> query = new JPAQuery<>(entityManager);
List<User> deletableUsers = query
.select(user)
.from(user)
.join(someTable)
.on(user.id.eq(someTable.user.id))
.where(user.notIn(createSubquery(compareDate))
.and(condition1)
.and(condition2)
.and(condition3)
.distinct()
.fetch();
private JPQLQuery<User> createSubquery(Date compareDate) {
return JPAExpressions
.select(user)
.from(user)
.join(someOtherTable)
.on(user.id.eq(someOtherTable.user.id))
.where((condition4
.and(condition5)
.and(condition6)))
.distinct();
}
Currently, we're using this query from within a #Service class but I wonder if it might make sense to move that to the Spring repository, so that all "query related" methods are located in the repository.
Is such an approach feasible, i.e. do you see any impediments like injecting the EntityManager into the repository?
Would you rather recommend to use the #Query annotation despite the query string getting long and complex?
I was doing a project and there i had a requirement of using pageable object and recieved page object from JPA.
Does anyone have any idea on how to use this?
#Repository
public interface CustomerRepository extends JpaRepository<Customer,Long>{
#Query("SELECT * FROM WHERE name=?1 AND surname=?2 ", nativeQuery = true)
List<Customer> findAllByNameAndSurname(String name,String surname);
}
I want a page List for result fetch from this query.
Spring Data JPA and native queries with pagination is not supported in Spring. According to documentation , Spring Data JPA repositories can be used with native queries and pagination. But, in real life Spring Data JPA (1.10.2.RELEASE) requires some additional fix.
You have to use this if you want pagination support.
List<Customer> customers = customerRepository.findAllByNameAndSurname(name,username);
PagedListHolder<Customer> pages = new PagedListHolder(customers);
pages.setPage(currentPageNumber); //set current page number
pages.setPageSize(pageSize); // set the size of page
pages.getPageList(); // return the list of items(or in your case List<Customer> ) of current page
Try this:
#Repository
public interface CustomerRepository extends JpaRepository<Customer, Long> {
Page<Customer> findAllByNameEqualsAndSurnameEquals(String name, String surname, Pageable pageable);
}
I am pretty sure JpaRepository can handle your Pageable parameter.
Also, method name has to be as I mentioned as spring creates queries based on method name (uses reflection).
If you really need to execute NATIVE QUERY you will have to find other solution but I do not recommend the one provided by Dasari Swaroop Kumar as it just queries all objects from database and then kinda filters it in memory.
Also to that native query solution - you can extend your method definition to additional 2 parameters for page and pageSize and append them to your native query and leave repository to return plain List and then create PageImpl object in the layer that calls your CustomerRepository object.
I am able to get the property value in Spring classes like below:
#Value("${database.name}")
private String databaseName;
I have to execute a native query by joining different tables which are in different databases.
#Query(value="select t1.* FROM db1.table1 t1 INNER JOIN db2.table2 t2 ON t2.t1_id1 = t1.id1")
Instead of hard coding database names i.e., db1 and db2 here, I have to get them from properties file.
how to get the property value inside the #Query annotation in Spring Data JPA Repository ?
I don't know if it is possible, but if not, you can consider this approach:
Instead of using properties in Repository's #Query directly, you can use params in the query but when you call the actual method - you can provide values from .properties.
Imagine you have simple repository:
public interface UserRepository extends JpaRepository<User, Long> {
// query with param
#Query("select u from User u where u.lastname = :lastname")
User findByLastname(#Param("lastname") String lastname);
}
Then, let's say you have some Service or Controller where you need to use your Repository - you can inject properties there and pass them to your method:
#Service
public class UserService {
// this comes from .properties
#Value("${user.lastName}")
private String userLastName;
#Autowired
private UserRepository userRepository;
public User getUser() {
// you pass it as param to the repo method which
// injects it into query
return userRepository.findByLastname(userLastName);
}
}
This is just an example. But I believe it may be useful.
Happy hacking :)
This code in my repository :
public interface ClientRepository extends CrudRepository<Client, Long> {
//#Transactional
#Modifying
#Query("update Client c set c.firstName = ?1, c.lastName = ?2, c.email = ?3 where c.id = ?4")
void updateClientInfoById(String firstname, String lastname, String email, Long userId);
Executing this method(updateClientInfoById) using a REST Service give me this exception : javax.persistence.TransactionRequiredException: Executing an update/delete query
I Have to add #Transactional to get it works.
why methods in repository are not all transactional by default ?
Thanks in advance :)
Only CRUD methods are by default marked as transactional. You are using custom query methods so you should explicitly mark it with #Transactional annotation.
Additionally, we can get rid of the #Transactional annotation for the
method as the CRUD methods of the Spring Data JPA repository
implementation are already annotated with #Transactional.
For more informations, see Getting started with Spring Data JPA
EDIT : CRUD methods are CrudRepository methods
I'm trying to move my project to Spring Boot 2.0.0.M2
Now Spring Data uses Optional for findBy* methods, like:
Optional<T> findById(ID id);
I have a Neo4j entities that contain the id property, for example:
#NodeEntity
public class Tag {
private Long id;
}
#Repository
public interface TagRepository extends Neo4jRepository<Tag, Long>
Tag findById(Long tagId);
}
id is a plain property and not and entity identifier(PK).
Prior Spring Boot 2.0 I used repository.findOne() embedded method in order to look up entity by it's identifier(PK) and my custom repository.findById() in order to look up entity by its id property.
Right now with Spring Boot 2.0 we don't have findOne and instead of this we have findById method finds the entity by PK. Right now I don't know how to provide my custom repository.findById method i order to be able to look up entity by ID property(not PK). Please advise.
If the field tagId exists in the entity you can use
Tag findByTagId(long tagId);
if not use
#Query("select t from Tag t where t.tagId = :tagId")
Tag getByTagId(#Param("tagId") long tagId);