I'm confused in S. H. Annotation. Here is my code
for my first class:
#Entity
#Table(name="player")
public class Player implements Serializable
{
#Id
#Column(name="id_player")
#GeneratedValue(strategy=GenerationType.IDENTITY)
private int id;
private String name;
private String pseudo;
}
and my second class:
#Entity
#Table(name="team")
public class Team implements Serializable
{
#Id
#Column(name="id_team")
#GeneratedValue(strategy=GenerationType.IDENTITY)
private int id;
private String name;
#OneToMany(fetch = FetchType.LAZY, mappedBy = "player")
private Set<Player> players = new HashSet<Player>();
}
it throws the exception:
mappedBy reference an unknown target entity property:
Player.Team in Team.players
i have getters and setters in these class.
how can i make it works? Thank you!
Add this in Player Class:
#ManyToOne(fetch = FetchType.LAZY)
private Team team;
And replace in Team Class:
mappedBy = "player" ----> mappedBy = "team"
Related
So I've been trying the solutions out there to map a ManyToMany relationship with extra columns but none of them is working for me and I don't know what am I doing wrong.
The Many to Many relationship is between Patient and Disease (a Patient can have multiple diseases and a Disease can be suffered by many Patients). The time attribute means "the type of the disease" (acute, chronic...)
My classes are:
#Entity
#Table(name="patient")
public class Patient{
#Id
#NotNull
#Column(name="nss")
private String NSS;
//Some attributes
#OneToMany(mappedBy = "patient")
private Set<PatientDisease> diseases = new HashSet<PatientDisease>();
//Empty constructor and constructor using fields omitted
//Getters and setters ommited
}
,
#Entity
#Table(name="disease")
public class Disease{
#Id
#GeneratedValue(strategy=GenerationType.IDENTITY)
#Column(name="id")
private Integer id;
#OneToMany(mappedBy = "disease")
private Set<PatientDisease> patients = new HashSet<PatientDisease>();
//Constructors and getters and setters ommited for brevity
}
Associated class
#Entity
#Table(name = "Patient_Disease")
#IdClass(PatientDiseaseID.class)
public class PatientDisease{
#Id
#ManyToOne(fetch = FetchType.LAZY,
cascade = {CascadeType.PERSIST, CascadeType.MERGE, CascadeType.REFRESH, CascadeType.DETACH})
#JoinColumn(name = "nssPatient", referencedColumnName = "id")
private Patient patient;
#Id
#ManyToOne(fetch = FetchType.LAZY,
cascade = {CascadeType.PERSIST, CascadeType.MERGE, CascadeType.REFRESH, CascadeType.DETACH})
#JoinColumn(name = "diseaseID", referencedColumnName = "id")
private Disease disease;
#Column(name="time")
private String time;
//GETTERS AND SETTERS OMMITED FOR BREVETY. Constructor NOT Needed following the example
}
The id class:
#Embeddable
public class PatientDiseaseId implements Serializable {
private static final long serialVersionUID = 1L;
#Column(name = "nssPatient")
private String patient;
#Column(name = "diseaseID")
private Integer disease;
//getters and setters
//hashCode and equals
}
My main app:
...
List<Diseases> diseases = sesion.createQuery("from Disease").getResultList();
System.out.println("Diseases: ");
for(Disease d: diseases) {
System.out.println(d.getName());
for(PatientDisease pd: e.getPatientDisease()) {
System.out.println(pd.getPatient().toString());
}
}
...
When running the main App I get the exception on line 5 (2nd for loop):
Exception in thread "main" org.hibernate.PropertyAccessException: Could not set field value [1] value by reflection : [class entities.PatientDisease.diseases] setter of entities.PatientDisease.diseases
I have tried some solutions here in Stack Overflow an some others that I found on the Internet, but I can't get them to work and I don't know why
Because you are using #IdClass you don't need to annotate PatientDiseaseId with #Embedded and #Column. And you have to refer to the entities.
This is what it should look like:
public class PatientDiseaseId implements Serializable {
private static final long serialVersionUID = 1L;
private Patient patient;
private Disease disease;
//getters and setters
//hashCode and equals
}
I am trying some hibernate.The following is the pojo I am using,
#Entity
#Table(name = "person")
public class Person {
#Id
#GeneratedValue
#Column(name = "person_id")
private long person_id;
#Column(name = "name")
private String name;
#Column(name = "Address")
private String Address;
#OneToMany(fetch = FetchType.EAGER, mappedBy = "person" )
private Set<Phone> phone;
//Getters ande Setters
}
#Entity
#Table(name = "phone")
public class Phone{
#Id
#GeneratedValue
#Column(name = "phone_id")
private long phone_id;
#Column(name = "name")
private String name;
#ManyToOne(cascade = CascadeType.MERGE,fetch = FetchType.EAGER)
#JoinColumn(name = "person_id")
private Person person ;
//Getters ande Setters
}
What I want is when I fetch a record from person and need corresponding all phone details. (Like Select * from person) I have around 1360 data in person and nearly double in phone. But for some reason error is thrown. I am not able to see full error stack . Below is the error I am getting.
at
com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:505)
~[jackson-databind-2.4.6.jar:2.4.6] at
com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:639)
~[jackson-databind-2.4.6.jar:2.4.6] at
com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:152)
~[jackson-databind-2.4.6.jar:2.4.6] at
com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:505)
~[jackson-databind-2.4.6.jar:2.4.6] at
com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:639)
~[jackson-databind-2.4.6.jar:2.4.6] at
com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:152)
~[jackson-databind-2.4.6.jar:2.4.6] at
com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serializeContents(CollectionSerializer.java:117)
~[jackson-databind-2.4.6.jar:2.4.6] at
com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serializeContents(CollectionSerializer.java:23)
~[jackson-databind-2.4.6.jar:2.4.6] at
.....
I was not able to post all error that I got
Using JsonManagedReference and JsonBackReference annotations may solve your problem.
While jackson trying to convert objects to json, visits objects and
their attributes. So if objects have bi-directional relations, for
jackson we need to think about cyclic dependencies. Jackson starts
serialize person and see the phone list and take a phone from list and
start serialize phone and sees person in phone and take person from
phone and start serilize it bla bla bla so this is an endless loop. If
jackson sees these annotations, stops and breaks the loop.
Give it a try as below code;
#Entity
#Table(name = "person")
public class Person {
#Id
#GeneratedValue
#Column(name = "person_id")
private long person_id;
#Column(name = "name")
private String name;
#Column(name = "Address")
private String Address;
#JsonManagedReference
#OneToMany(fetch = FetchType.EAGER, mappedBy = "person" )
private Set<Phone> phone;
// Getters and Setters
}
#Entity
#Table(name = "phone")
public class Phone{
#Id
#GeneratedValue
#Column(name = "phone_id")
private long phone_id;
#Column(name = "name")
private String name;
#ManyToOne(cascade = CascadeType.MERGE,fetch = FetchType.EAGER)
#JoinColumn(name = "person_id")
#JsonBackReference
private Person person;
// Getters and Setters
}
You can alternatively use #JsonIdentityInfo on classes
#Entity
#JsonIdentityInfo(generator=ObjectIdGenerators.IntSequenceGenerator.class, property="#id")
#Table(name = "phone")
public class Phone {
}
#Entity
#JsonIdentityInfo(generator=ObjectIdGenerators.IntSequenceGenerator.class, property="#id")
#Table(name = "person")
public class Person {
}
I was also getting the same error.
Using #JsonBackReference and #JsonManagedReference was still giving me error so I used #JsonIdentityInfo and it worked like a charm.
Below are my classes :-
BookModel :
#Data
#Entity
#Table(name = "book")
#JsonIdentityInfo(generator=ObjectIdGenerators.IntSequenceGenerator.class, property="bookId")
public class BookModel implements Serializable{
/**
*
*/
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "book_id")
private int bookId;
#Column(name="book_name")
private String bookName;
#Column(name="book_author")
private String bookAuthor;
#Column(name="book_publish_date")
private Date bookPublishDate;
#Column(name="book_price")
private double bookPrice;
#OneToMany(mappedBy = "book_model")
List<BookImagesModel> bookImagesModels;
//getters and setters
//default constructor
}
BookImagesModel :
#Data
#Entity
#Table(name = "book_images")
#JsonIdentityInfo(generator=ObjectIdGenerators.IntSequenceGenerator.class, property="imageId")
public class BookImagesModel implements Serializable {
/**
*
*/
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "image_id")
private long imageId;
#ManyToOne
#JoinColumn(name = "book_id")
private BookModel book_model;
#Column(name = "image_path")
private String imagePath;
//getters and setters
//default constructor
}
I used Mysql8 database with spring boot.
I'm using ebean with play framework and I have a problem mapping a many-many relationship between 2 join tables. Let's say we have 3 entities, Person, Company, and Profession. A Person can have many Professions. A Person can work for many Companies. And a Company can employ many Persons in many Professions.
Here's my code:
#Entity
public class Company extends Model {
#Id
public Long id;
#OneToMany(fetch = FetchType.LAZY, mappedBy = "company")
public List<CompanyPerson> companyPersons;
#OneToMany(fetch = FetchType.LAZY, mappedBy = "company")
public List<CompanyProfession> companyProfessions;
...
}
#Entity
public class Profession extends Model {
#Id
public Long id;
#OneToMany(fetch = FetchType.LAZY, mappedBy = "profession")
public List<CompanyProfession> companyProfessions;
...
}
#Entity
public class Person extends Model {
#Id
public Long id;
#OneToMany(fetch = FetchType.LAZY, mappedBy = "person")
public List<CompanyPerson> companyPersons;
...
}
#Entity
public class CompanyPerson extends Model {
#EmbeddedId
public CompanyPersonId id = new CompanyPersonId();
#ManyToOne
#JoinColumn(name = "company_id")
private Company company;
#ManyToOne
#JoinColumn(name = "person_id")
private Person person;
#ManyToMany(mappedBy = "companyPersons")
public List<CompanyProfession> companyProfessions;
...
}
#Entity
public class CompanyProfession extends Model {
#EmbeddedId
public CompanyProfessionId id = new CompanyProfessionId();
#ManyToOne
#JoinColumn(name = "company_id")
private Company company;
#ManyToOne
#JoinColumn(name = "profession_id")
private Person person;
#ManyToMany(cascade = CascadeType.ALL)
public List<CompanyPerson> companyPersons;
...
}
I get the following error:
Error injecting constructor, javax.persistence.PersistenceException: Error with the Join on [models.CompanyProfession.companyPersons]. Could not find the local match for [null] Perhaps an error in a #JoinColumn
at play.db.ebean.EbeanDynamicEvolutions.(EbeanDynamicEvolutions.java:36)
I tried adding JoinColumn(name = "companyperson_id") but that just changed the error from [null] to [companyperson_id].
Not sure what to do here. Any help?
I have a to make a one-to-one association between two Entities, but one of them must have two #Id. One is PRI another one is MUL. How must i declare composite id, and how do i need to map the classes?
#Entity
#Table(name = "PERSONS")
public class Person implements Serializable{
private static final long serialVersionUID = -3451407520028311143L;
#Id
#Column(name = "ID")
private Integer id;
#Column(name = "ADDRESS_ID")
private Integer addressId;
#Column(name ="NAME")
private String name;
#OneToOne(mappedBy= "person", cascade= CascadeType.ALL)
private Address address;
...
}
second class is mapped via #IdClass annotation
#Entity
#Table ( name = "ADDRESS" )
#IdClass(AddressKeys.class)
public class Address implements Serializable {
#Id
#Column ( name = "ID")
private Integer id;
#Id
#Column ( name = "PERSON_ID")
private Integer idPerson;
#Column ( name = "CITY" )
private String city;
#OneToOne(cascade= CascadeType.ALL)
#JoinColumn(name="PERSON_ID")
private Person person;
...
}
and the id class
class AddressKeys implements Serializable{
private Integer id;
private Integer idPerson;
//getters and setters
#Override
public int hashCode() {
...
return result;
}
#Override
public boolean equals(Object obj) {
...
}
}
So when i try to create and save a record i have a next error
Could not open sessionRepeated column in mapping for entity:
hibernateMappedModels.base1.mappedClasses.oneToOne.Address column:
PERSON_ID (should be mapped with insert="false" update="false")
java.lang.NullPointerException at
hibernateMappedModels.base1.Main.run(Main.java:45) at
hibernateMappedModels.base1.Main.main(Main.java:24
I tryed to make an Id fields unInsertable and unUpdatable, and it was working, but i need them to be insertable and updatable; Is there any possibility to do it?
I am confused by your mappings and not sure what is required other then the simple mappings below: if I am missing something then you will need to expand on your question. You are getting the error as you have mapped the column twice - once via the one-to-one and once as a simple property. Additionally, I am not sure why you require a composite key on address.
#Entity
#Table(name = "PERSONS")
public class Person implements Serializable{
private static final long serialVersionUID = -3451407520028311143L;
#Id
#Column(name = "ID")
private Integer id;
#Column(name ="NAME")
private String name;
#OneToOne(mappedBy= "person", cascade= CascadeType.ALL)
private Address address;
}
#Entity
#Table ( name = "ADDRESS" )
public class Address implements Serializable {
#Id
#Column ( name = "ID")
private Integer id;
#Column ( name = "CITY" )
private String city;
#OneToOne(cascade= CascadeType.ALL)
#JoinColumn(name="PERSON_ID")
private Person person;
}
I have the following two classes, one ReqCandAssociation can have many Comments and it is mapped like so. I need to figure out a way that when I delete a ReqCandAssociation it deletes all of its associated comments. Thanks
#Entity
#Table(name = "candidate_jobReq")
public class ReqCandAssociation implements Serializable {
#Id
private Integer candidateId;
#Id
private Integer jobId;
#Column(name = "reqStatus")
private String reqStatus;
#ManyToOne
#PrimaryKeyJoinColumn(name="candidateId", referencedColumnName="id")
private Candidate candidate;
#ManyToOne
#PrimaryKeyJoinColumn(name="jobId", referencedColumnName="id")
private JobReq jobReq;
public ReqCandAssociation(){
}
Second class
#Entity
#Table(name="comment")
public class Comment {
#Id
#GeneratedValue(strategy=GenerationType.IDENTITY)
private Integer id;
#Column(name="commentText")
private String commentText;
#Column(name="commentDate")
private Date commentDate;
#ManyToOne
#PrimaryKeyJoinColumn(name="reqCandAssociationId", referencedColumnName="id")
private ReqCandAssociation reqCandAssociation;
#ManyToOne
#PrimaryKeyJoinColumn(name="userId", referencedColumnName="id")
private User user;
Change this to the following, i'm making it bidirectional mapping.
#Entity
#Table(name = "candidate_jobReq")
public class ReqCandAssociation implements Serializable {
#Id
private Integer candidateId;
#Id
private Integer jobId;
#Column(name = "reqStatus")
private String reqStatus;
#OneToMany(cascade = { CascadeType.ALL }) //this is added here.
#JoinColumn(name ="reqCandAssociationId")
private Set<Comment> comments;
-----
Readup more on the cascade options. All cascade types are all|none|save-update|delete|all-delete-orphan|delete-orphan
The cascade all will delete all the comments associated to this class.