spring-data-jpa - w3toppers.com

What is difference between CrudRepository and JpaRepository interfaces in Spring Data JPA?

JpaRepository extends PagingAndSortingRepository which in turn extends CrudRepository. Their main functions are: CrudRepository mainly provides CRUD functions. PagingAndSortingRepository provides methods to do pagination and sorting records. JpaRepository provides some JPA-related methods such as flushing the persistence context and deleting records in a batch. Because of the inheritance mentioned above, JpaRepository will have all the functions … Read more

Spring-Data-Jpa Repository – Underscore on Entity Column Name

I solved this error by renaming field to the name without underscore. @Column(name = “municipal_id”, nullable = false) private Integer municipalId; // <– field was renamed

Spring data jpa – How to combine multiple And and Or through method name

Agree with Oliver on long and unreadable method names, but nevertheless and for the sake of argument, you can achieve desired result by using the equivalency A /\ (B \/ C) <=> (A /\ B) \/ (A /\ C) A and (B or C) <=> (A and B) or (A and C) So in your … Read more

How does the FetchMode work in Spring Data JPA

I think that Spring Data ignores the FetchMode. I always use the @NamedEntityGraph and @EntityGraph annotations when working with Spring Data @Entity @NamedEntityGraph(name = “GroupInfo.detail”, attributeNodes = @NamedAttributeNode(“members”)) public class GroupInfo { // default fetch mode is lazy. @ManyToMany List<GroupMember> members = new ArrayList<GroupMember>(); … } @Repository public interface GroupRepository extends CrudRepository<GroupInfo, String> { @EntityGraph(value … Read more

POSTing a @OneToMany sub-resource association in Spring Data REST

Assuming you already have discovered the post URI and thus the URI of the association resource (considered to be $association_uri in the following), it generally takes these steps: Discover the collection resource managing comments: curl -X GET http://localhost:8080 200 OK { _links : { comments : { href : “…” }, posts : { href … Read more

When use getOne and findOne methods Spring Data JPA

TL;DR T findOne(ID id) (name in the old API) / Optional<T> findById(ID id) (name in the new API) relies on EntityManager.find() that performs an entity eager loading. T getOne(ID id) relies on EntityManager.getReference() that performs an entity lazy loading. So to ensure the effective loading of the entity, invoking a method on it is required. … Read more

Spring Data JPA – ZonedDateTime format for json serialization

I guess that you are using Jackson for json serialization, Jackson now has a module for Java 8 new date time API, https://github.com/FasterXML/jackson-datatype-jsr310. Add this dependency into your pom.xml <dependency> <groupId>com.fasterxml.jackson.datatype</groupId> <artifactId>jackson-datatype-jsr310</artifactId> <version>2.6.0</version> </dependency> And this is its usage: public static void main(String[] args) throws JsonProcessingException { ObjectMapper objectMapper = new ObjectMapper(); objectMapper.registerModule(new JavaTimeModule()); System.out.println(objectMapper.writeValueAsString(new … Read more

Using generics in Spring Data JPA repositories

First of all, I know we’re raising the bar here quite a bit but this is already tremendously less code than you had to write without the help of Spring Data JPA. Second, I think you don’t need the service class in the first place, if all you do is forward a call to the … Read more

How to do bulk (multi row) inserts with JpaRepository?

To get a bulk insert with Spring Boot and Spring Data JPA you need only two things: set the option spring.jpa.properties.hibernate.jdbc.batch_size to appropriate value you need (for example: 20). use saveAll() method of your repo with the list of entities prepared for inserting. Working example is here. Regarding the transformation of the insert statement into … Read more

setMaxResults for Spring-Data-JPA annotation?

As of Spring Data JPA 1.7.0 (Evans release train). You can use the newly introduced Top and First keywords that allow you to define query methods like this: findTop10ByLastnameOrderByFirstnameAsc(String lastname); Spring Data will automatically limit the results to the number you defined (defaulting to 1 if omitted). Note that the ordering of the results becomes … Read more