Develop Reference

Hibernate. How to select child entities with a several parent fields with writing all it in parent entity

I have a next question: while working with Hibernate 3.3.0 run into a situation when I have two tables with one-to-many relationships and I need to get the list of parents. In each entity must be filled the several fields from the parent table and a list of all children mapped in the parent. For the easiest understanding, I give an example. I have two tables with one-to-many relationships: parent is "recipients" and child is "requisites". And I have two classes whose objects are the rows of these tables. Class for the table of recipients:
#Entity
#Table(name = "recipients")
#JsonFilter(value = "recipientsFilter")
public class POJORecipient implements POJO {
private static final long serialVersionUID = 4436819032452218525L;
#Id
#Column
private long id;
#Version
#Column
private long version;
#Column(name = "client_id")
private long clientId;
#Column
private String inn;
#Column
private String name;
#Column(name = "rcpt_country_code")
private String rcptCountryCode;
#Column(name = "rcpt_passp_ser")
private String rcptPasspSer;
#Column(name = "rcpt_passp_num")
private String rcptPasspNum;
#OneToMany(mappedBy = "recipient", fetch = FetchType.LAZY)
#JsonManagedReference
private Set<POJORequisite> requisites = new HashSet<>();
public POJORecipient(){}
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
public long getVersion() {
return version;
}
public void setVersion(long version) {
this.version = version;
}
public long getClientId() {
return clientId;
}
public void setClientId(long clientId) {
this.clientId = clientId;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getInn() {
return inn;
}
public void setInn(String inn) {
this.inn = inn;
}
public String getRcptCountryCode() {
return rcptCountryCode;
}
public void setRcptCountryCode(String rcptCountryCode) {
this.rcptCountryCode = rcptCountryCode;
}
public String getRcptPasspSer() {
return rcptPasspSer;
}
public void setRcptPasspSer(String rcptPasspSer) {
this.rcptPasspSer = rcptPasspSer;
}
public String getRcptPasspNum() {
return rcptPasspNum;
}
public void setRcptPasspNum(String rcptPasspNum) {
this.rcptPasspNum = rcptPasspNum;
}
public Set<POJORequisite> getRequisites() {
return requisites;
}
public void setRequisites(Set<POJORequisite> requisites) {
this.requisites = requisites;
}
}
and for requisites table:
#Entity
#Table(name = "requisites")
public class POJORequisite implements POJO {
private static final long serialVersionUID = -35864567359179960L;
#Id
#Column
private long id;
#Version
#Column
private long version;
#Column
private String bic;
#Column
private String bill;
#Column
private String comments;
#Column
private String note;
#ManyToOne
#JoinColumn(name = "recipient_id")
#JsonBackReference
private POJORecipient recipient;
public POJORequisite(){}
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
public long getVersion() {
return version;
}
public void setVersion(long version) {
this.version = version;
}
public String getBic() {
return bic;
}
public void setBic(String bic) {
this.bic = bic;
}
public String getBill() {
return bill;
}
public void setBill(String bill) {
this.bill = bill;
}
public String getComments() {
return comments;
}
public void setComments(String comments) {
this.comments = comments;
}
public String getNote() {
return note;
}
public void setNote(String note) {
this.note = note;
}
public POJORecipient getRecipient() {
return recipient;
}
public void setRecipient(POJORecipient recipient) {
this.recipient = recipient;
}
}
So, I want to select from the recipients only names and all mapped requisites. Consequently, after the selection, I will have a list of POJORecipient objects and in each object filled only the field "name" and set of POJORequisite objects.
As answer of my question I want to discover one of next: how can I do that with help HQL or Criteria API (the second variant is preferable), or understand it is impossible in Hibernate at all, or that this possibility appeared in later versions (also preferably with example). I'm trying to resolve this question for several months now and will be immensely grateful for any help. All clarifications and advices also will be so helpful. Thanks in advance!!!

JPA update a object creates a new one in a ManyToMany Relation

I'm having issues while trying to update objects with JPA. The problem instead of updating an existing object, it creates new ones along with new embedded data.
Here is my java code:
First entity
#Entity
#Table(name = "worksite")
public class Worksite {
private long id;
private String name;
private Double longitude;
private Double latitude;
private Set<WorksiteDevice> worksiteDevices = new HashSet<WorksiteDevice>();
#Id
#GeneratedValue(strategy = GenerationType.SEQUENCE)
#Column(name = "worksite_id")
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Double getLongitude() {
return longitude;
}
public void setLongitude(Double longitude) {
this.longitude = longitude;
}
public Double getLatitude() {
return latitude;
}
public void setLatitude(String latitude) {
this.latitude = latitude;
}
#OneToMany(mappedBy = "worksite", fetch = FetchType.LAZY, cascade = CascadeType.ALL, orphanRemoval = true )
public Set<WorksiteDevice> getWorksiteDevices() {
return worksiteDevices;
}
public void setWorksiteDevices(Set<WorksiteDevice> worksiteDevices) {
this.worksiteDevices = worksiteDevices;
}
}
Second Entity:
the device name has a unique constraint in the database. This is to prevent the user from entering the same device multiple times
#Entity
#Table(name = "device")
public class Device {
private long id;
private String DeviceName;
private Set<WorksiteDevice> worksiteDevices = new HashSet<WorksiteDevice>();
#Id
#GeneratedValue(strategy = GenerationType.SEQUENCE)
#Column(name = "device_id")
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
public String getDeviceName() {
return name;
}
public void setName(String name) {
this.deviceName = name;
}
#OneToMany(mappedBy = "device", fetch = FetchType.LAZY, cascade = CascadeType.ALL, orphanRemoval = true)
public Set<WorksiteDevice> getWorksiteDevices() {
return worksiteDevices;
}
public void setWorksiteDevices(Set<WorksiteDevice> worksiteDevices) {
this.worksiteDevices = worksiteDevices;
}
Join Table:
#Entity
#Table(name = "worksite_device")
public class WorksiteDevice {
private long id;
private Worksite worksite;
private Device device;
// additional fields
private Integer deviceCount;
#Id
#GeneratedValue(strategy = GenerationType.SEQUENCE)
#Column(name = "worksite_device_id")
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumn(name = "worksite_id")
private Worksite worksite;
public void setWorksite(Worksite worksite) {
this.worksite = worksite;
}
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumn(name = "device_id")
public void setDevice(Device device) {
this.device = device;
}
public Integer getDeviceCount() {
return deviceCount;
}
public void setDeviceCount(Integer deviceCount) {
this.deviceCount = deviceCount;
}
}
I have a DTO class in which I get from the user interface the name of the devices and the number of devices used in a worksite.
public class WorksiteDeviceDTO extends BaseDTO{
private Long id;
private int deviceCount;
private String deviceName;
private Worksite worksite;
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public Integer getDeviceCount() {
return deviceCount;
}
public void setDeviceCount(Integer deviceCount) {
this.deviceCount = deviceCount;
}
public String getDeviceName() {
return deviceName;
}
public void setDeviceName(String deviceName) {
deviceName = deviceName;
}
}
I save the DTO objects in a list that I iterate before saving in the database. Here is how i do this:
I save first the worksite object and then the number of devices and names used in a worksite
worksiteService.saveWorksite(worksite);
final Map<String, Geraete> deviceByName = worksiteDeviceDtos.stream()
.map(worksiteDeviceDTO::getDeviceName)
.map(this::getOrSaveDeviceByName)
.collect(Collectors.toMap(
Device::getDeviceName,
Function.identity()));
worksiteDeviceDtos.forEach(worksiteDeviceDTO -> {
final WorksiteDevice toSave = new WorksiteDevice();
toSave.setWorksite(worksite);
toSave.setDevice(deviceByName.get(worksiteDeviceDTO.getDeviceName()));
toSave.setDeviceCount(worksiteDeviceDTO.getDeviceCount());
worksiteDeviceService.saveWorksiteDevice(toSave);
I check with this Method if a Devicename already in a Database exist. If so, I'll get it back. If not, I create a new Object with the new name.
#Transactional
public Device getOrSaveDeviceByName(String DeviceName) {
return DeviceNameService.findByName(DeviceName)
.orElseGet(() -> geraeteService.saveNewGeraetWithName(DeviceName));
}
when I change the name of a device in the user interface and I keep the number of devices, a new object is created with the modified name. I don't know how to solve this problem. Someone would have an idea. I also tried to work with a compound key but I had the same problem

It seems you are creating and saving a new instance all the time, regardless if you "found" a device by that name. You should filter out the elements that you found.

JPA get join table data condition [duplicate]

When I send a GET request in POSTMAN to get all my child entity (Town) the parent entity (Province) is not shown in the JSON response.
This is my controller.
#RequestMapping(value ="api/v1/town",method = RequestMethod.GET)
public ResponseEntity<List<Town>> getAllTowns() {
List<Town> towns = townService.getAllTowns();
if(towns.isEmpty()) {
return new ResponseEntity<List<Town>>(HttpStatus.NO_CONTENT);
}
return new ResponseEntity<List<Town>>(towns, HttpStatus.OK);
}
And these are my entities.
Parent Class
#Entity
#Table(name = "PROVINCE")
public class Province {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name = "PROVINCE_ID")
private long id;
private String name;
#OneToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL, mappedBy = "province", targetEntity = Town.class)
#JsonManagedReference("Province-Town")
private List<Town> towns;
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public List<Town> getTowns() {
return towns;
}
public void setTowns(List<Town> towns) {
this.towns = towns;
}
}
Child Class
#Entity
#Table(name = "TOWN")
public class Town {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name = "TOWN_ID")
private long id;
private String name;
#ManyToOne(cascade = CascadeType.MERGE)
#JoinColumn(name = "PROVINCE_ID")
#JsonBackReference("Province-Town")
private Province province;
private long kilometer;
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Province getProvince() {
return province;
}
public void setProvince(Province province) {
this.province = province;
}
public long getKilometer() {
return kilometer;
}
public void setKilometer(long kilometer) {
this.kilometer = kilometer;
}
}
The response that I'm getting is like this
{
"id" : 1,
"name" : "Some Town",
"kilometer" : 350
}
What I'm expecting is
{
"id" : 1,
"name" : "Some Town",
"province" : {
//Province data.....
}
"kilometer" : 350
}
I was able to show something like this, but the Objects that I used are not Spring-data-jpa entities, just simple POJOs.
Is there any problem with my Entities? Or is there anything else?

Swap #JsonBackReference and #JsonManagedReference. Basically:
#JsonManagedReference
private Province province;
#JsonBackReference
private List<Town> towns;

Can not set int field com.java.hibernate.practise.User.id to java.util.HashSet

I have hibernate #OneToMany mapping I am getting the mentioned error. Does not understand the reason. As getters and setters are public
Below are the entities
#Entity
#Table(name="USER_DETAILS")
public class User implements Serializable {
/**
*
*/
private static final long serialVersionUID = 1L;
#Id
#Column(name="USER_ID")
#GeneratedValue(strategy=GenerationType.AUTO)
private int id;
#Column(name="USER_FIRSTNAME",nullable=false, length=50)
private String userFirstName;
#Column(name="USER_LASTNAME",nullable=false, length=50)
private String userLastName;
#Column(name="USER_MIDDLENAME",length = 30)
private String userMiddleName;
#Column(name="USER_AGE")
private int userAge;
#Column(name="USER_SEX")
private String userSex;
#OneToMany(cascade=CascadeType.ALL, mappedBy="userAddress", targetEntity=Address.class)
private Set<Address> address = new HashSet<Address>();
public String getUserFirstName() {
return userFirstName;
}
public void setUserFirstName(String userFirstName) {
this.userFirstName = userFirstName;
}
public String getUserLastName() {
return userLastName;
}
public void setUserLastName(String userLastName) {
this.userLastName = userLastName;
}
public String getUserMiddleName() {
return userMiddleName;
}
public void setUserMiddleName(String userMiddleName) {
this.userMiddleName = userMiddleName;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public int getUserAge() {
return userAge;
}
public void setUserAge(int userAge) {
this.userAge = userAge;
}
public String getUserSex() {
return userSex;
}
public void setUserSex(String userSex) {
this.userSex = userSex;
}
public Set<Address> getAddress() {
return address;
}
public void setAddress(Set<Address> address) {
this.address = address;
}
}
#Entity
#Table(name = "ADDRESS")
public class Address implements Serializable {
/**
*
*/
private static final long serialVersionUID = 1L;
#Id
#Column(name = "ADDRESS_ID")
#GeneratedValue(strategy=GenerationType.AUTO)
private int id;
#Column(name = "ZIP_CODE")
private String zipCode;
#Column(name="ADDRESS_USER_ID", insertable=false, updatable=false)
private Long addressUserID;
#Column(name = "ADDRESS_SEC")
private String addressSec;
#Column(name = "STREET")
private String street;
#Column(name = "CITY")
private String city;
#Column(name = "COUNTRY")
private String country;
#ManyToOne(cascade=CascadeType.ALL, targetEntity=User.class)
#JoinColumn(name="ADDRESS_USER_ID")
private Set<User> userAddress = new HashSet<User>();
public Long getAddressUserID() {
return addressUserID;
}
public void setAddressUserID(Long addressUserID) {
this.addressUserID = addressUserID;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getZipCode() {
return zipCode;
}
public void setZipCode(String zipCode) {
this.zipCode = zipCode;
}
public Set<User> getUserAddress() {
return userAddress;
}
public void setUserAddress(Set<User> userAddress) {
this.userAddress = userAddress;
}
public String getStreet() {
return street;
}
public void setStreet(String street) {
this.street = street;
}
public String getCity() {
return city;
}
public void setCity(String city) {
this.city = city;
}
public String getAddressSec() {
return addressSec;
}
public void setAddressSec(String addressSec) {
this.addressSec = addressSec;
}
public String getCountry() {
return country;
}
public void setCountry(String country) {
this.country = country;
}
}
Part of Stack Trace are:
Exception in thread "main" org.hibernate.PropertyAccessException: could not get a field value by reflection getter of com.java.hibernate.practise.User.id at... org.hibernate.property.DirectPropertyAccessor$DirectGetter.get(DirectPropertyAccessor.java:62)
Caused by: java.lang.IllegalArgumentException: Can not set int field com.java.hibernate.practise.User.id to java.util.HashSet...
I am generating the schema using hibernate.hbm2ddl.auto= cerate-drop
Please guide on this.

Generally when we use 1..n bidirectional entity mapping, the owning side which is in general, the many side, should have only a single instance reference to the one side object (not a collection - that would be many to many), and the join column to use is the primary key from the on side class. We don't need to explicitly use the FK column in the many side like you are.
So if this is your relationship User [1]..[N] Address, then you should have something more like
public class User {
...
#OneToMany(mappedBy = "user", cascade=CascadeType.ALL)
private Set<Address> addresses;
}
public class Address {
// private Long addressUserID; // Don't need this property. We get it below
...
#ManyToOne
#JoinColumn(name = "USER_ID")
private User user;
}

How to prevent endless loop in hibernate

I have a rest server and client which uses this API. I have a list of hotels and it had passed well until I added bidirectional dependencies to other entities.After that I start receive an endless array of entities which just repeat the same row in database.
It is my first project with hibernate so may be I made trivial mistakes of novice.
Hotel:
#Entity
#Table(name = "hotels", schema = "", catalog = "mydb")
public class HotelsEntity implements HospitalityEntity{
private int idHotel;
private String name;
private String region;
private String description;
// private byte[] photo;
private HotelPropertyEntity property;
private List<RoomEntity> rooms;
#OneToOne(mappedBy = "hotel")
public HotelPropertyEntity getProperty() {
return property;
}
public void setProperty(HotelPropertyEntity property) {
this.property = property;
}
#OneToMany(mappedBy = "hotel")
public List<RoomEntity> getRooms() {
return rooms;
}
public void setRooms(List<RoomEntity> rooms) {
this.rooms = rooms;
}
#Id
#Column(name = "id_hotel", unique = true)
#GeneratedValue(strategy=GenerationType.AUTO)
public int getIdHotel() {
return idHotel;
}
public void setIdHotel(int idHotel) {
this.idHotel = idHotel;
}
#Basic
#Column(name = "name")
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
#Basic
#Column(name = "region")
public String getRegion() {
return region;
}
public void setRegion(String region) {
this.region = region;
}
#Basic
#Column(name = "description")
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
HotelProperty
#Entity
#Table(name = "hotel_property", schema = "", catalog = "mydb")
public class HotelPropertyEntity {
private int idHotelProperty;
private byte hasPool;
private byte hasTennisCourt;
private byte hasWaterslides;
private HotelsEntity hotel;
#Id
#Column(name = "id_hotel_property", unique = true)
#GeneratedValue(strategy=GenerationType.AUTO)
public int getIdHotelProperty() {
return idHotelProperty;
}
public void setIdHotelProperty(int idHotelProperty) {
this.idHotelProperty = idHotelProperty;
}
#Basic
#Column(name = "has_pool", columnDefinition = "BIT", length = 1)
public byte getHasPool() {
return hasPool;
}
public void setHasPool(byte hasPool) {
this.hasPool = hasPool;
}
#Basic
#Column(name = "has_tennis_court", columnDefinition = "BIT", length = 1)
public byte getHasTennisCourt() {
return hasTennisCourt;
}
public void setHasTennisCourt(byte hasTennisCourt) {
this.hasTennisCourt = hasTennisCourt;
}
#Basic
#Column(name = "has_waterslides", columnDefinition = "BIT", length = 1)
public byte getHasWaterslides() {
return hasWaterslides;
}
public void setHasWaterslides(byte hasWaterslides) {
this.hasWaterslides = hasWaterslides;
}
#OneToOne(cascade = CascadeType.ALL)
#JoinColumn(name = "id_hotel_property")
public HotelsEntity getHotel() {
return hotel;
}
public void setHotel(HotelsEntity hotel) {
this.hotel = hotel;
}
Room:
#Entity
#Table(name = "room", schema = "", catalog = "mydb")
public class RoomEntity {
private int idRoom;
private String roomType;
private int peopleCapacity;
private Boolean booked;
private Boolean locked;
private HotelsEntity hotel;
private InventoriesEntity inventory;
private RoomPropertyEntity roomProperty;
#OneToOne(mappedBy = "room")
public RoomPropertyEntity getRoom() {
return roomProperty;
}
public void setRoom(RoomPropertyEntity roomProperty) {
this.roomProperty = roomProperty;
}
#OneToOne
#JoinColumn(name = "id_room")
public InventoriesEntity getInventory() {
return inventory;
}
public void setInventory(InventoriesEntity inventory) {
this.inventory = inventory;
}
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumn(name = "id_hotel")
public HotelsEntity getHotel() {
return hotel;
}
public void setHotel(HotelsEntity hotel) {
this.hotel = hotel;
}
#Id
#Column(name = "id_room")
public int getIdRoom() {
return idRoom;
}
public void setIdRoom(int idRoom) {
this.idRoom = idRoom;
}
#Basic
#Column(name = "room_type")
public String getRoomType() {
return roomType;
}
public void setRoomType(String roomType) {
this.roomType = roomType;
}
#Basic
#Column(name = "people_capacity")
public int getPeopleCapacity() {
return peopleCapacity;
}
public void setPeopleCapacity(int peopleCapacity) {
this.peopleCapacity = peopleCapacity;
}
#Basic
#Column(name = "booked", columnDefinition = "BIT", length = 1)
public Boolean getBooked() {
return booked;
}
public void setBooked(Boolean booked) {
this.booked = booked;
}
#Basic
#Column(name = "locked", columnDefinition = "BIT", length = 1)
public Boolean getLocked() {
return locked;
}
public void setLocked(Boolean locked) {
this.locked = locked;
}
Could you please advise what is a way or ways to tell hibernate to stop this cycle?
p.s
This code contains another one issue. I f I remove one to one dependency and remain only one to many I receive failed to lazily initialize a collection of role: com.example.model.HotelsEntity.rooms, could not initialize proxy - no Session (through reference chain: java.util.ArrayList[0]->com.example.model.HotelsEntity["rooms"])

You need to mark entity as not serializable for JSON. Please use #JsonIgnore or #JsonIgnoreProperties("field") on one of the sides of the relations (the annotation is class-level).