I have Certificate class that contains list of Tag classes
import javax.persistence.*;
import java.math.BigDecimal;
import java.time.LocalDateTime;
import java.util.List;
import java.util.Objects;
#Entity
#Table(name = "gift_certificate")
public class Certificate {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String name;
private String description;
private BigDecimal price;
private Integer duration;
#Column(name = "create_date")
private LocalDateTime createDate;
#Column(name = "last_update_date")
private LocalDateTime lastUpdateDate;
#ManyToMany
#JoinTable(name = "gift_certificate_tag",
joinColumns = #JoinColumn(name = "tag_id"),
inverseJoinColumns = #JoinColumn(name = "gift_certificate_id")
)
private List<Tag> tags;
getters and setters and other code...
....
import javax.persistence.*;
import java.util.Objects;
#Entity
#Table(name = "tag")
public class Tag {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String name;
getters and setters and other code...
And I'm trying to get List of Certificate from DB using JPA/Hibernate.
I'm using EntityManager
public List<Tag> getCertificateTags(Long certificateId) {
return entityManager.createQuery("select c.tags from Certificate c where c.id=:id")
.setParameter("id", certificateId)
.getResultList();
}
And it works, but I get just list, not List and IDEA is warning Unchecked assignment: 'java.util.List' to 'java.util.List<Tag>'.
And when I use createQuery with second parameter Tag.class like this:
entityManager.createQuery("select c.tags from Certificate c where c.id=:id", Tag.class)
.setParameter("id", certificateId)
.getResultList();
I get java.lang.IllegalArgumentException: Type specified for TypedQuery [Tag] is incompatible with query return type [interface java.util.Collection]
How can I fix it?
Try to change the query this way
select t from Certificate c join c.tags t where c.id=:id
The reason is that select c.tags means every result row contains a list of tags. But when you select t from Certificate c join c.tags t every row contains one tag
Related
Hi everyone I'm working with SpringBoot and I want to send the ID's of table Producto and Cliente to Pedidos, I'm using the constructor for to pass of parametrs
I tried to create a List as String to hold the values and then use it to send the data to the other method
Class Product
package com.example.demo.model;
import java.util.Set;
import javax.persistence.*;
#Entity
#Table(name = "Productos")
public class Producto {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String nombreProducto;
private String precioProducto;
/*Here i send of FK of this table to Pedidos*/
#OneToMany(mappedBy = "producto",cascade = CascadeType.ALL)
private Set<Pedido> pedidos;
public Producto(String nombreProducto, String precioProducto) {
this.nombreProducto = nombreProducto;
this.precioProducto = precioProducto;
}
//Getters and Setters
}
Class Cliente
package com.example.demo.model;
import java.util.Set;
import javax.persistence.*;
#Entity
#Table(name="Clientes")
public class Cliente {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String nombreCliente;
private String correoElectronico;
/*Here i send of FK of this table to Pedidos*/
#OneToMany(mappedBy = "cliente",cascade = CascadeType.ALL)
private Set<Pedido> pedidos;
public Cliente(String nombreCliente, String correoElectronico) {
this.nombreCliente = nombreCliente;
this.correoElectronico = correoElectronico;
}
//Getters and Setters
}
Class Pedido
package com.example.demo.model;
import javax.persistence.*;
#Entity
#Table(name = "Pedido")
public class Pedido {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String fechaPedido;
private String direccion;
/*
Here I create the atribute of FK of the tables Cliente and Producto
*/
#ManyToOne(cascade = CascadeType.ALL)
#JoinColumn(name = "cliente_id", referencedColumnName = "id")
private Cliente cliente;
#ManyToOne(cascade = CascadeType.ALL)
#JoinColumn(name = "producto_id", referencedColumnName = "id")
private Producto producto;
public Pedido(String fechaPedido, String direccion, Cliente cliente, Producto producto) {
this.fechaPedido = fechaPedido;
this.direccion = direccion;
this.cliente = cliente;
this.producto = producto;
}
//Getters and Setters
}
And the last Class it's the RunnClass
package com.example.demo;
import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.IntStream;
//import java.util.stream.Stream;
import org.springframework.boot.CommandLineRunner;
import org.springframework.stereotype.Component;
import com.example.demo.model.Cliente;
import com.example.demo.model.Pedido;
import com.example.demo.model.Producto;
import com.example.demo.repository.ClienteRepository;
import com.example.demo.repository.PedidosRepository;
import com.example.demo.repository.ProductoRepositroy;
import com.github.javafaker.Faker;
#Component
public class SampleDataLoader implements CommandLineRunner {
private final ClienteRepository clienteRepository;
private final ProductoRepositroy productoRepositroy;
private final PedidosRepository pedidosRepository;
private final Faker faker; //It's a ASI of DataFaker
public SampleDataLoader(ClienteRepository clienteRepository,
ProductoRepositroy productoRepositroy,
PedidosRepository pedioPedidosRepository) {
this.clienteRepository = clienteRepository;
this.productoRepositroy = productoRepositroy;
this.pedidosRepository = pedioPedidosRepository;
this.faker = new Faker(); //It's a ASI of DataFaker
}
#Override
public void run(String... args) throws Exception {
ejecutarClases();
}
private void ejecutarClases() {
List<Cliente> clientes = IntStream.rangeClosed(1, 20)
.mapToObj(i -> new Cliente(faker.name().fullName(),
faker.internet().emailAddress()))
.collect(Collectors.toList());
clienteRepository.saveAll(clientes);
List<Producto> productos = IntStream.rangeClosed(1, 100)
.mapToObj(i -> new Producto(faker.commerce().productName(), "$"+faker.commerce().price()))
.collect(Collectors.toList());
productoRepositroy.saveAll(productos);
//I don't know how to send two ID's to this table,
//if you can see I have two values as null
//I want to send the ID's the other tables
List<Pedido> pedidos = IntStream.rangeClosed(1, 30)
.mapToObj(i -> new Pedido(faker.backToTheFuture().date(),
faker.address().streetAddress(), null, null))
.collect(Collectors.toList());
pedidosRepository.saveAll(pedidos);
}
}
I hope someone can help me please.
My API shows me infinite loop for adress field
When I insert #JsonIgnore, #JsonManagedReference or #JsonBackReference
I can clearly see one result as it should be, but than i don't have nested address fields.
What should I do to have also that address fields but one result?
These are my main entities:
1.Property
package com.realestate.petfriendly.entity;
import com.fasterxml.jackson.annotation.JsonBackReference;
import com.fasterxml.jackson.annotation.JsonIgnore;
import java.io.Serializable;
import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.OneToOne;
import javax.persistence.Table;
import lombok.Data;
#Entity
#Data
#Table(name = "property")
public class Property {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "id_property")
private int id_property;
#Column(name = "title")
private String title;
#Column(name = "type")
private String type;
#Column(name = "room")
private String room;
#Column(name = "price")
private double price;
#OneToOne(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
#JoinColumn(name = "address_id_address")
// #JsonBackReference
private Address address;
#ManyToOne(fetch = FetchType.LAZY, optional = false)
#JoinColumn(name = "user_id_user")
// #JsonBackReference
private User user;
}
User
package com.realestate.petfriendly.entity;
import com.fasterxml.jackson.annotation.JsonManagedReference;
import java.util.ArrayList;
import java.util.List;
import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.OneToMany;
import javax.persistence.OneToOne;
import javax.persistence.Table;
import lombok.Getter;
import lombok.Setter;
#Entity
#Getter
#Setter
#Table(name = "user")
class User {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "id_user")
private int id_user;
#Column(name = "username")
private String username;
#Column(name = "name")
private String name;
#Column(name = "lastname")
private String lastname;
#Column(name = "phone")
private String phone;
#Column(name = "notes")
private String notes;
#OneToOne(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
#JoinColumn(name = "user_address_id_user_address")
// #JsonManagedReference
private UserAddress userAddress;
#OneToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL, mappedBy = "user")
// #JsonManagedReference
private List<Property> property = new ArrayList<>();
}
Address
package com.realestate.petfriendly.entity;
import com.fasterxml.jackson.annotation.JsonManagedReference;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.OneToOne;
import javax.persistence.Table;
import lombok.Getter;
import lombok.Setter;
#Entity
#Getter
#Setter
#Table(name="address")
class Address{
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "id_address")
private int id_address;
#Column(name = "city")
private String city;
#Column(name = "municipality")
private String municipality;
#Column(name = "place")
private String place;
#Column(name = "street")
private String street;
#Column(name = "house_number")
private double house_number;
#OneToOne(mappedBy = "address")
// #JsonManagedReference
private Property property;
}
You actually have the solution to your problem in your code, but the key annotations are commented-out and in the wrong places (according to your requirements). One of the ways to tackle this is by using #JsonManagedReference and #JsonBackReference as follows:
#Entity
#Data
#Table(name = "property")
public class Property {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "id_property")
private int id_property;
#Column(name = "title")
private String title;
#Column(name = "type")
private String type;
#Column(name = "room")
private String room;
#Column(name = "price")
private double price;
#OneToOne(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
#JoinColumn(name = "address_id_address")
#JsonManagedReference
private Address address;
#ManyToOne(fetch = FetchType.LAZY, optional = false)
#JoinColumn(name = "user_id_user")
#JsonBackReference
private User user;
}
#Entity
#Getter
#Setter
#Table(name = "user")
class User {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "id_user")
private int id_user;
#Column(name = "username")
private String username;
#Column(name = "name")
private String name;
#Column(name = "lastname")
private String lastname;
#Column(name = "phone")
private String phone;
#Column(name = "notes")
private String notes;
#OneToOne(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
#JoinColumn(name = "user_address_id_user_address")
private UserAddress userAddress;
#OneToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL, mappedBy = "user")
#JsonManagedReference
private List<Property> property = new ArrayList<>();
}
#Entity
#Getter
#Setter
#Table(name="address")
class Address{
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "id_address")
private int id_address;
#Column(name = "city")
private String city;
#Column(name = "municipality")
private String municipality;
#Column(name = "place")
private String place;
#Column(name = "street")
private String street;
#Column(name = "house_number")
private double house_number;
#OneToOne(mappedBy = "address")
#JsonBackReference
private Property property;
}
Keep in mind the following:
#JsonManagedReference is the forward part of the relationship: the one that gets serialized normally.
#JsonBackReference is the back part of the relationship: it will be omitted from serialization.
If you want to have a reference to the back part of the relationship, you can use #JsonIdentityInfo as follows:
#Entity
#Data
#Table(name = "property")
#JsonIdentityInfo(
generator = ObjectIdGenerators.PropertyGenerator.class,
property = "id_property")
public class Property {
(...)
}
#Entity
#Getter
#Setter
#Table(name = "user")
#JsonIdentityInfo(
generator = ObjectIdGenerators.PropertyGenerator.class,
property = "id_user")
class User {
(...)
}
#Entity
#Getter
#Setter
#Table(name="address")
#JsonIdentityInfo(
generator = ObjectIdGenerators.PropertyGenerator.class,
property = "id_address")
class Address{
(...)
}
You can read more about these and other techniques in the following online resource: https://www.baeldung.com/jackson-bidirectional-relationships-and-infinite-recursion.
You have circular dependency between Property and Address class. In order to block infinite JSON serialization loop you can add #JsonIgnore annotation on one side of related properties
I'm a beginner with spring and I have this little issue. "No property questionId found for type CourseTestCompleteField!" I have 2 model classes that are connected via a one to one join.
That 2 model class are:
package com.example.springboot.models;
import javax.persistence.*;
import javax.validation.constraints.NotBlank;
#Entity
#Table(name = "questions")
public class CourseTestQuestion {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name="question_id")
private Long id;
#NotBlank
#Column(name = "question_course")
private String questionCourse;
#NotBlank
#Column(name = "question_type")
private String questionType;
public CourseTestQuestion(){
}
public CourseTestQuestion(String questionCourse, String questionType) {
this.questionCourse = questionCourse;
this.questionType = questionType;
}
// public getters and setters for all fields here
}
And:
package com.example.springboot.models;
import javax.persistence.*;
import javax.validation.constraints.NotBlank;
#Entity
#Table(name = "quiz_complete_field_questions",
uniqueConstraints = {
#UniqueConstraint(columnNames = "question_id")
}
)
public class CourseTestCompleteField {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#NotBlank
#Column(name = "question_content")
private String questionContent;
#NotBlank
#Column(name = "answer")
private String answer;
#NotBlank
#Column(name = "points")
private String points;
#NotBlank
#Column(name = "course")
private String course;
#NotBlank
#Column(name = "teacher_username")
private String teacher;
#OneToOne(cascade = CascadeType.ALL)
#JoinColumn(name = "question_id", referencedColumnName = "question_id")
private CourseTestQuestion courseTestQuestion;
public CourseTestCompleteField(){
}
public CourseTestCompleteField(CourseTestQuestion courseTestQuestion, String question, String answer, String points, String course, String teacher) {
this.courseTestQuestion = courseTestQuestion;
this.questionContent = question;
this.answer = answer;
this.points = points;
this.course = course;
this.teacher = teacher;
}
// public getters and setters for all fields here
}
My repo for both:
package com.example.springboot.repository;
import com.example.springboot.models.Course;
import com.example.springboot.models.CourseTestQuestion;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;
import java.util.Optional;
#Repository
public interface CourseTestQuestionRepository extends JpaRepository<CourseTestQuestion, Long> {
Optional<CourseTestQuestion> findById(Long id);
Optional<CourseTestQuestion> findByQuestionCourse(String questionCourse);
}
And:
package com.example.springboot.repository;
import com.example.springboot.models.CourseTestCompleteField;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;
import java.util.List;
import java.util.Optional;
#Repository
public interface CourseTestCompleteFieldRepository extends JpaRepository<CourseTestCompleteField, Long> {
Optional<CourseTestCompleteField> findById(Long id);
Optional<CourseTestCompleteField> findByQuestionId(Long questionId);
Optional<CourseTestCompleteField> findByCourse(String course);
List<CourseTestCompleteField> findByQuestionContent(String questionContent);
List<CourseTestCompleteField> findByTeacher(String teacher);
Boolean existsByQuestionContent(String questionContent);
}
The problem is with Optional<CourseTestCompleteField> findByQuestionId(Long questionId);but I don't get it why, because in database I have the table for CourseTestCompleteFieldModel with question_id column, and in CourseTestCompleteField I have CourseTestQuestion object. Tho, the table for CourseTestCompleteField has a different name, could be this a problem? I should rename the table to course_test_complete_field?
Can someone help me please? Thank you
Since,This is a query on nested Object. You need to update your query as this.
Optional<CourseTestCompleteField> findByCourseTestQuestion_Id(Long questionId);
This works even without "_"
Optional<CourseTestCompleteField> findByCourseTestQuestionId(Long questionId);
But better to put "_" while accessing nested fields for better readability.
There is no field call questionId in you entity and you have id only.
That's you got error. You can use that findyById(). That's only enough.
If you would like write JPA repository method like findBy..., getBy..., deleteBy...., countBy..., After this you need append exact field name from entity.
For example if you entity have name then can write below methods. findByName(); deleteByName(); countByName();
So try as below.
findBycourseTestQuestion(Object o);
Pass questions object.
I have 3 entities -
Course
Module
Timeline
Course is an independent entity with following attributes:
Course - (id Integer Primary Key, course_name)
#Id
#Column(name = "id")
Integer courseId;
#Column(name = "course_name")
String course_name;
Next up is another entity Module,
Every row in module is related to one course, and hence there is a one to one relationship between Module and Course.
Module - (module_id, module_name, module_type, duration)
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name = "module_id")
Integer module_id;
#Column(name = "module_name")
String module_name;
#Column(name = "duration")
Integer duration;
#ManyToOne
#JoinColumn(name="timeline_id", nullable=false)
private Timeline timeline;
Now, next is a timeline entity, which is also related to course i.e every timeline id belongs to one course id, but one timeline id can belong to multiple module_ids, and hence below code:
#Id
#Column(name = "timeline_id")
Integer timelineId;
#OneToMany( mappedBy = "timeline" )
private List<Module> module;
#OneToOne( cascade = CascadeType.ALL)
private Course course;
Can you please tell me what is the error over here.
ModuleRepository:
#Repository
public interface ModuleRepository extends JpaRepository<Module, Integer>{
public List<Module> findAllByTimelineTimelineId(Integer timelineId);
}
IModuleService
public interface IModuleService {
public List<Module> findByTimelineId(Integer timelineId);
}
ModuleServiceImpl
public List<Module> findByTimelineId(Integer timelineId) {
// TODO Auto-generated method stub
return moduleRepo.findAllByTimelineTimelineId(timelineId);
}
Controller
#RequestMapping("/gettimeline/{timeline_id}")
public List<Module> findByTimelineId(#PathVariable Integer timeline_id){
return moduleService.findByTimelineId(timeline_id);
}
Now when I run this url in Postman: http://localhost:8083/gettimeline/1
I get an infinite loop, I am unable to decode the error, also is there any problem with OneToMany mapping, I am new to JPA:
[{"module_id":1,"module_name":"Sleep","duration":10,"timeline":{"timelineId":1,"module":[{"module_id":1,"module_name":"Sleep","duration":10,"timeline":{"timelineId":1,"module":[{"module_id":1,"module_name":"Sleep","duration":10,"timeline":{"timelineId":1,"module":[{"module_id":1,"module_name":"Sleep","duration":10,"timeline":{"timelineId":1,"module":[{"module_id":1,"module_name":"Sleep","duration":10,"timeline":{"timelineId":1,"module":[
Please help, thank you in advance :)
The infinite loop issue is caused by the one-to-many relation. There are several ways of fixing this, but I find view model classes like shown below as the cleanest approach.
Please note that the owning side of the one-to-many relation is not included in the code below, only the many-to-one. This can be done the other way around, but from your code, I guess this is what you want.
TimelineVM class
package no.mycompany.myapp.misc;
import lombok.Data;
import lombok.NoArgsConstructor;
#Data
#NoArgsConstructor
public class TimelineVM {
private Integer timelineId;
public TimelineVM(Timeline timeline) {
this.timelineId = timeline.getTimelineId();
}
}
ModuleVM class
package no.mycompany.myapp.misc;
import lombok.Data;
import lombok.NoArgsConstructor;
#Data
#NoArgsConstructor
public class ModuleVM {
private Integer module_id;
private String module_name;
private Integer duration;
private TimelineVM timeline;
public ModuleVM(Module module) {
this.module_id = module.getModule_id();
this.module_name = module.getModule_name();
this.duration = module.getDuration();
this.timeline = new TimelineVM(module.getTimeline());
}
}
Controller method
#RequestMapping("/gettimeline/{timeline_id}")
public List<ModuleVM> findByTimelineId(#PathVariable Integer timeline_id){
return moduleService.findByTimelineId(timeline_id).stream().map(ModuleVM::new).collect(Collectors.toList());
}
I am creating an API where I have 3 tables called User, Book and Status. And I want to create a combined table User_Book_Status. I am not sure how to implement this in JPA. I think all tables have M:N relationship with each other. How should I join these 3 tables?
Here is my design for the database.
User.java
import javax.persistence.*;
#Entity
#Table(name = "users")
public class User {
#Id
#GeneratedValue(strategy = GenerationType.SEQUENCE)
private long id;
#Column(nullable = false)
private String username;
#Column(nullable = false)
private String password;
public User() {}
//Getters and setters omitted.
}
Book.java
import javax.persistence.*;
#Entity
#Table(name = "books")
public class Book {
#Id
#GeneratedValue(strategy = GenerationType.SEQUENCE)
private long id;
#Column(nullable = false)
private String title;
#Column(nullable = false)
private String author;
#Column(nullable = false)
private int pages;
public Book() {}
//Getters and setters omitted.
}
Status.java
import javax.persistence.*;
#Entity
public class Status {
public enum ReadingStatus {READING,
FINISHED,
ONHOLD}
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private long id;
#Enumerated(EnumType.STRING)
private ReadingStatus status;
}
here is an example of how to implement your solution already working:
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.Table;
#Entity
#Table(name = "user_book_status")
public class UserBookStatus {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private long id;
#ManyToOne
#JoinColumn(name = "user_id")
private User user;
#ManyToOne
#JoinColumn(name = "book_id")
private Book book;
#ManyToOne
#JoinColumn(name = "status_id")
private Status status;
}
#Table to specify the name of the Table, so you can change the name of the entity freely.
#ManyToOne means that you can have many records of UserBookStatus for a single user, or book or status.
#JoinColumn use to specify the name of the column in your entity that maps to the #Id from the entity (User,Book,Status) you are referencing.
It seems to me that you don't really need an entity for Status. I would model it like this:
#Entity
public class Loan {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private long id;
#ManyToOne
private Book book;
#ManyToOne
private User user;
#Enumerated(EnumType.STRING)
private ReadingStatus status;
//...
}
Also, you could make the relationships bidirectional, so that both User and Bookhas a list of Loans.