I have object like this:
#Entity
public class DocumentationRecord {
#Id
#GeneratedValue
private long id;
private String topic;
private boolean isParent;
#OneToMany
private List<DocumentationRecord> children;
...
}
now I would like to get only topics and ids. Is there way to get it in format like this:
[
{
id: 4234234,
topic: "fsdfsdf"
},...
]
Because even using only this query
public interface DocumentationRecordRepository extends CrudRepository<DocumentationRecord, Long> {
#Query("SELECT d.topic as topic, d.id as id FROM DocumentationRecord d")
List<DocumentationRecord> getAllTopics();
}
I was only able to get record like this:
[
[
"youngChild topic",
317
],
[
"oldChild topic",
318
],
[
"child topic",
319
],
]
I don't like array of arrays I would like to get array of object with property id and topic. What is the nicest way to achieve that?
In Spring Data JPA you can use projections:
Interface based:
public interface IdAndTopic {
Long getId();
String getTopic();
}
Class based (DTO):
#Value // Lombok annotation
public class IdAndTopic {
Long id;
String topic;
}
Then create a simple query method in your repo:
public interface DocumentationRecordRepository extends CrudRepository<DocumentationRecord, Long> {
List<IdAndTopic> findBy();
}
You can create even dynamic query method:
List<T> findBy(Class<T> type);
Then use it like this:
List<DocumentationRecord> records = findBy(DocumentationRecord.class);
List<IdAndTopic> idAndTopics = findBy(IdAndTopic.class);
You can create a class with attributes id and topic and use constructor injection into query. Sth like below
#Query("SELECT NEW your.package.SomeObject(d.id, d.topic) FROM DocumentationRecord d")
Related
Is it possible to use JPA derived methods and query by example at the same time?
Let's imagine i have two entities like this:
#Entity
#Data
public class Person {
#Id
#GeneratedValue
Long id
String name;
String surname;
#OneToMany
List<Dog> dogs;
}
#Entity
#Data
public class Dog{
#Id
#GeneratedValue
Long id
String name;
}
I'd like to be able to do something like this (just an example):
Person p = new Person ();
p.setName("Mario");
personRepository.findDistinctByDogsIsNotNull(Example.of(p));
The Example.of(p) only works if i do findAll, but it doesn't work if i define inside the repository a method like this
private interface PersonRepository extends JpaRepository<Person, Long>{
List<Person> findDistinctByDogsIsNotNull(Example<Person> example)
}
The error it gives me is something like this:
Failed to create query for method public abstract java.util.List dev.cele.test.repository.PersonRepository.findDistinctByDogIsNotNull(org.springframework.data.domain.Example)! At least 1 parameter(s) provided but only 0 parameter(s) present in query.
So my question is: is it possible to do a query by example in a JPA derived query method?
And if it's not possible how can i create some sort of parametrizable query that also has a predetermined condition?
Hi I have implemented a mock solution to my problem and I'm pretty sure something better already exist.
Here's that I want to achieve :
I have created a point to load categories with or without subCategories
/api/categories/1?fields=subCategories
returns
{
"id":"1",
"name":"test",
"subCategories":[{
"id":"1",
"name":"test123"
}]
}
/api/categories/1
returns
{
"id":"1",
"name":"test"
}
My entities
#Entity
class Category{
#Id
private String id;
private String name;
private Set<SubCategory> subCategories;
}
#Entity
class SubCategory{
#Id
private String id;
private String name;
}
I have removed services since this is not the point.
I've created CategoryDTO and SubCategoryDTO classes with the same fields as Category and SubCategory
The converter
class CategoryDTOConverter{
CategoryDTO convert(Category category,String fields){
CategoryDTO dto=new CategoryDTO();
dto.setName(category.getName());
if(StringUtils.isNotBlank(fields) && fields.contains("subCategories"){
category.getSubCategories().forEach(s->{
dto.getSubcategories().add(SubCategoryDTOConverter.convert(s));
}
}
}
}
I used com.cosium.spring.data.jpa.entity.graph.repository to create an EntityGraph from a list of attribute path
#Repository
interface CategoryRepository extends EntityGraphJpaRepository<Category, String>{
Optional<T> findById(String id,EntityGraph entityGraph);
}
Controller
#RestController
#CrossOrigin
#RequestMapping("/categories")
public class CategoryController {
#GetMapping(value = "/{id}")
public ResponseEntity<CategoryDTO> get(#PathVariable("id") String id, #RequestParam(value="fields",required=false) String fields ) throws Exception {
Optional<Category> categOpt=repository.findById(id,fields!=null?EntityGraphUtils.fromAttributePaths(fields):null);
if(categOpt.isEmpty())
throws new NotFoundException();
return ResponseEntity.ok(categoryDTOConverter.convert(categOpt.get(),fields);
}
}
This is a simple example to illustrate what I need to do
I don't want to load fields that clients doesn't want to use
How could I do this in a better way ?
Take a look at GraphQL since it is a perfect match for your use case. With GraphQL it is the client that decides which attributes it wants to receive by providing in the POST request body exactly which attributes are needed to be included in the response. This is way more manageable than trying to handle all this on your own.
Spring Boot recently added its own Spring GraphQL library, so it is quite simple to integrate it in your Spring Boot app.
Model Class Vehicle
#Column(name="type",nullable=false)
private String type;
#Column(name="last_service_date",nullable=false)
private String lastServiceDate;
#Column(name="seats",nullable=false)
private Long seats;
#Column(name="bags_capacity",nullable=false)
private Long bagsCapacity;
#Column(name="milage",nullable=false)
private Long milage;
//for Franchise object id
private transient Long fId;
#ManyToOne
#JoinColumn(name="franchise_id")
private Franchise fkFranchiseId;
#Repository
public interface VehicleRepository extends JpaRepository<Vehicle,Long>
{
}
I am using spring data jpa repositories and want to search Vehicle by type and foreignKey=>(zipcode) how can i find
Just add a method in your Vehicle JPA repository interface as follow:
findAllByTypeAndFkFranchiseIdZipCode(String type, String zipCode);
And also you are welcome to check docs of Spring Data Jpa
List<Vehicle> findAllByTypeAndFkFranchiseId_ZipCode(String type, String zipCode);
You can use JPA repo method name query documented here https://docs.spring.io/spring-data/jpa/docs/current/reference/html/#jpa.query-methods.query-creation
public interface VehicleRepo extends JpaRepository<Vehicle, String> {
List<Vehicle> findAllByTypeAndFkFranchiseIdZipCode((String type, String zipCode);
Page<Vehicle> findAllByTypeAndFkFranchiseIdZipCode((String type, String zipCode,Pageable page);
}
for those who have a more complex object and want to keep their code, u can also use #Query for fetching data.
u just need to do this like this:
#Repository
public interface VehicleRepo extends JpaRepository<Vehicle, String> {
#Query("from Vehicle v where v.type = :type and v.fkFranchise.zipCode = :zipCode")
List<Vehicle> findAllByTypeAndZipCode(String type, String zipCode);
}
I'm setting a server to get a CRUD api from a postgresql Database using JPA. Everytime I want to expose an object from the DB it duplicate the idObject.
When I get an object from the database using springframework and send it after that, it duplicate the idObject like this:
{
"siteId": 3,
"contractId": "1",
"name": "sitenumber1",
"siteIdObject": {
"siteId": 3,
"contractId": "1"
}
}
SiteId and contractId are repeating...
but I want something like that:
{
"siteId": 3,
"contractId": "1",
"name": "sitenumber1"
}
I want to avoid using DTO because I think there is a better way but I don't find it. Since I'm using springFramework for just one or two month I'm maybe forgeting something...
there is the code:
Site code:
#Entity
#IdClass(SiteId.class)
#Table(name = "site", schema="public")
public class Site {
#Id
#Column(name="siteid")
private Integer siteId;
#Id
#Column(name="clientid")
private Integer contractId;
private String name;
#JsonIgnore
#OneToMany(cascade=CascadeType.ALL, mappedBy = "site")
public Set<Device> devices;
//setter, getter, hash, equals, tostring, constructor empty one and full one
SiteId code:
public class SiteId implements Serializable {
private Integer siteId;
private Integer contractId;
// setter, getter, constructor empty and full, hash and equals
Thanks to help :)
Bessaix Daniel
If you are using Spring you might also be using Jackson so if you annotate your SiteIdclass with #JsonIgnoreType it shouldn't be serialized at all when the Site object is serialized.
I am however unsure if this will break your application logic now that the id object is not serialized anymore.
Suppose I have entities (getters/setters and various details omitted for brevity):
#Entity
class Customer{
...
#OneToMany(cascade = CascadeType.ALL, mappedBy = "customer")
Collection<Coupon> coupons;
}
#Entity
class Coupon{
...
#Temporal(value = TemporalType.TIMESTAMP)
private Date usedOn;
#ManyToOne(fetch = FetchType.LAZY)
#NotNull
Customer customer;
}
I wish retrieve all Coupons for a given Customer having null usedOn.
I,'ve unsuccessfully defined a method in the CouponRepository as described in docs
#Repository
public interface CouponRepository extends CrudRepository<Coupon, Long> {
Collection<Coupon> findByCustomerAndUsedOnIsNull(Customer);
}
but this leads on a compiler error Syntax error, insert "... VariableDeclaratorId" to complete FormalParameterList.
My fault, the correct definition is
#Repository
public interface CouponRepository extends CrudRepository<Coupon, Long> {
Collection<Coupon> findByCustomerAndUsedOnIsNull(Customer customer);
}
I simply missed the parameter name :-(
You can use IsNull to check null columns in JPA query.
For example for any columnA you can write query like query like
findByColumnAIsNull
In this case you can write queries like
#Repository
public interface CouponRepository extends CrudRepository<Coupon, Long> {
Collection<Coupon> findByCustomerAndUsedOnIsNull(Customer customer);
List<Coupon> findByUsedOnIsNull();
}
Also you can check how this queries will be
Refer this Spring Data JPA Query creation this will help you lot to understand and create different type of JPA query variation.
https://docs.spring.io/spring-data/jpa/docs/current/reference/html/#jpa.query-methods.query-creation
Try changing your method to this (assuming Customer.id is a long):
Collection<Coupon> findByCustomer_IdAndUsedOnIsNull(Long customerId);
then use like this:
repo.findByCustomer_IdAndUsedOnIsNull(customer.getId());