I create application in Spring, which stores albums, musicians and bands. Album can contain multiple bands and musicians. I created association between Album and Band/Musician. Jet I am unable to delete it. I don't want to delete objects, just the association. I tried to send REST PUT request and setting musicians and bands to null on Album site, yet nothing happens:
{
"id": 2,
"title": "Lulu",
"bands": null,
"musicians": null,
"duration": {
"hours": 1,
"minutes": 20,
"seconds": 4
},
"releaseDate": "31/10/2011",
"coverPath": "https://upload.wikimedia.org/wikipedia/en/4/40/Lou_Reed_and_Metallica_-_Lulu.jpg",
"spotifyPath": null
}
I have created following class and method to link Album and Musician, yet I am unable to "unlink" them:
#RestController
public class AlbumMusicianController {
#Autowired
AlbumRepository albumRepository;
#Autowired
MusicianRepository musicianRepository;
#Transactional
#PostMapping("/musician/{musicianId}/album/{albumId}")
public List<Album> associate(#PathVariable Long musicianId, #PathVariable Long albumId) {
Album album = this.albumRepository.findById(albumId).orElseThrow(() -> new MissingResourceException("Album",
"Album", albumId.toString()));
return this.musicianRepository.findById(musicianId).map((musician) -> { musician.getAlbums().add(album);
return this.musicianRepository.save(musician).getAlbums();
}).orElseThrow(() -> new MissingResourceException("Musician", "Musician", musicianId.toString()));
}
}
Would be thankful for any help.
Below are necessary sources.
Album class:
#Entity
#Table(name="album")
#JsonIdentityInfo(
generator = ObjectIdGenerators.PropertyGenerator.class,
property = "id")
public class Album {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
#Column(name="title")
private String title;
#ManyToMany(targetEntity = Band.class, mappedBy = "albums")
#JsonSerialize(using = BandsSerializer.class)
private List<Band> bands;
#ManyToMany(targetEntity = Musician.class, mappedBy = "albums")
#JsonSerialize(using = MusiciansSerializer.class)
private List<Musician> musicians;
#Embedded
#Column(name="duration")
private Duration duration;
#Column(name="releasedate")
#JsonFormat(shape=JsonFormat.Shape.STRING, pattern="dd/MM/yyyy", timezone="CET")
private Date releaseDate;
#Column(name="coverpath")
private String coverPath;
#Column(name="spotifypath")
private String spotifyPath;
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public Duration getDuration() {
return duration;
}
public void setDuration(Duration duration) {
this.duration = duration;
}
public Date getReleaseDate() {
return releaseDate;
}
public void setReleaseDate(Date releaseDate) {
this.releaseDate = releaseDate;
}
public String getCoverPath() {
return coverPath;
}
public void setCoverPath(String coverPath) {
this.coverPath = coverPath;
}
public String getSpotifyPath() {
return spotifyPath;
}
public void setSpotifyPath(String spotifyPath) {
this.spotifyPath = spotifyPath;
}
public List<Band> getBands() {
return bands;
}
public void setBands(List<Band> bands) {
this.bands = bands;
}
public List<Musician> getMusicians() {
return musicians;
}
public void setMusicians(List<Musician> musicians) {
this.musicians = musicians;
}
}
Musician class:
#Entity
#Table(name="musician")
#JsonIdentityInfo(
generator = ObjectIdGenerators.PropertyGenerator.class,
property = "id")
public class Musician {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
#Column(name="name")
private String name;
#Column(name="surname")
private String surname;
#Column(name="birthdate")
#JsonFormat(shape=JsonFormat.Shape.STRING, pattern="dd/MM/yyyy", timezone="CET")
private Date birthDate;
#Column(name="picturepath")
private String picturePath;
#ManyToMany(cascade = CascadeType.ALL)
#JoinTable(name = "album_musician",
joinColumns = #JoinColumn(name = "album_id", referencedColumnName = "id"),
inverseJoinColumns = #JoinColumn(name = "musician_id",
referencedColumnName = "id"))
private List<Album> albums;
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 String getSurname() {
return surname;
}
public void setSurname(String surname) {
this.surname = surname;
}
public Date getBirthDate() {
return birthDate;
}
public void setBirthDate(Date birthDate) {
this.birthDate = birthDate;
}
public String getPicturePath() {
return picturePath;
}
public void setPicturePath(String picturePath) {
this.picturePath = picturePath;
}
public List<Album> getAlbums() {
return albums;
}
public void setAlbums(List<Album> albums) {
this.albums = albums;
}
}
Band class:
#Entity
#Table(name="band")
#JsonIdentityInfo(
generator = ObjectIdGenerators.PropertyGenerator.class,
property = "id")
public class Band {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
#Column(name="name")
private String name;
#Column(name="picturepath")
private String picturePath;
#ManyToMany(cascade = CascadeType.ALL)
#JoinTable(name = "album_band",
joinColumns = #JoinColumn(name = "album_id", referencedColumnName = "id"),
inverseJoinColumns = #JoinColumn(name = "band_id",
referencedColumnName = "id"))
#JsonSerialize(using = AlbumsSerializer.class)
private List<Album> albums;
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 String getPicturePath() {
return picturePath;
}
public void setPicturePath(String picturePath) {
this.picturePath = picturePath;
}
public List<Album> getAlbums() {
return albums;
}
public void setAlbums(List<Album> albums) {
this.albums = albums;
}
}
Based on your JSON body I'm going to assume you were sending a PUT request for the Album entity. There were two things that I found missing that got it to work for me after adjusting. I'm not sure if you were avoiding using them for one reason or another.
Cascade rules to cascade changes from Album to its relations.
Proper entity mapping for the join table from Album to its relations.
Not really sure why this was an issue - Hibernate did not seem to throw any exceptions related to this at execution time, but it did not seem to persist things correctly.
Here is an adjusted relation definition for Album's relation to Musician.
#ManyToMany(cascade = CascadeType.ALL)
#JoinTable(name="album_musician", joinColumns = #JoinColumn(name = "musician_id", referencedColumnName = "id"),
inverseJoinColumns = #JoinColumn(name = "album_id",
referencedColumnName = "id"))
private List<Musician> musicians;
In this format, I was able to cascade changes from Album to Musician. You will have to do something similar for the Band entity to cascade operations from Album to Band.
Related
I have the following scenario:
I have a Student class and students table.
I have Course class and courses table.
Every student and course have unique ID.
I would like to put a List into the Student class which is mapped by courses IDs.
I have tried a lot of annotations and relations but nothing succeeded
#Entity
#Table(name = "courses")
public class Course {
private long id;
private String name;
public Course() {
}
public Course(String name, int size) {
this.name = name;
this.size = size;
}
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
#Column(name = "name", nullable = false)
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
#Entity
#Table(name = "students")
public class Student {
private long id;
private String name;
#OneToMany(cascade = CascadeType.ALL)
private List<Course> courses = new ArrayList<>();
public Student() {
}
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
#Column(name = "name", nullable = false)
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public List<Course> getCourses() {
return courses;
}
public void setCourses(List<Course> courses) {
this.courses = courses;
}
}
Can you help me hot to achieve that because i am a little newbie into the spring
Use the following when declaring one to many relation
#Column(name="course_id")
private Set<Course> courses;
You need to use OneToMany annotation.
#OneToMany(mappedBy = "students", cascade = CascadeType.ALL)
private List<Course> courses;
You need to give your list a type. For instance
List<Courses> courseList = new ArrayList<>();
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;
I have 2 entities: Product and ProductLine. One Product can have many ProductLines. I am unable to delete the Product associated with a particular ProductLine.
Product.java
#Entity
#Table(name = "PRODUCT")
public class Product {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
private String name;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
}
ProductLine.java
#Entity
#Table(name = "PRODUCTLINE")
#JsonSerialize
public class ProductLine {
#JsonIgnore
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public List<Product> getProducts() {
return products;
}
public void setProducts(List<Product> products) {
this.products = products;
}
private String name;
#JsonIgnore
#OneToMany(cascade = CascadeType.ALL)
#JoinTable(name = "PRODUCTLINE_PRODUCT", joinColumns = #JoinColumn(name = "PRODUCTLINE_ID"), inverseJoinColumns = #JoinColumn(name = "PRODUCT_ID"))
private List<Product> products;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
}
You can find the entire code in - https://github.com/iftekharkhan09/ProductRepository.git
The Code is in Spring boot.
Please execute the below in postman:
Add product Line (POST)
http://localhost:8080/data/addProductLine?productLine=apple
Add Product to Product Line(POST)
http://localhost:8080/data/addProduct
body:
[
{
"productLine": "apple",
"productName":"mac"
}
,
{
"productLine": "apple",
"productName":"iphone"
}
]
TO delete the Product(POST) :-
http://localhost:8080/data/deleteProduct?productLineName=apple&productName=mac
In the console I can not see the delete query being fired.
Any help will be highly appreciated.
I am new to hibernate. I have requirement to introduce the delete functionality in hibernate with annotation. ie once we delete the parent, it needs to delete child records ie i need to introduce the ondelete cascade feature. Could you please help how to introduce this feature. please find below is java/entity code.
#Entity
#Table(name = "atfLabel", uniqueConstraints = #UniqueConstraint(columnNames = {"key_", "module_id"}))
#SuppressWarnings("serial")
public class Label {
private long id;
private ModuleImpl module;
private String key;
#Id
#GeneratedValue(strategy=GenerationType.AUTO)
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
#ManyToOne(optional=false)
#JoinColumn(name="module_id", nullable=false, updatable=false)
public ModuleImpl getModule() {
return module;
}
public void setModule(ModuleImpl module) {
this.module = module;
}
#Column(name="key_", length=160)
public String getKey() {
return key;
}
public void setKey(String key) {
this.key = key;
}
}
#Entity
#Table(name = "atfModule")
#SuppressWarnings("serial")
public class ModuleImpl implements Module {
private long id;
private String name;
private String description;
#OneToMany(mappedBy="module")
#Cascade(CascadeType.DELETE)
private List<Label> label;
#Override
#Id
#GeneratedValue(strategy=GenerationType.AUTO)
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
#Override
#Column(length=200, unique=true, nullable=false)
public String getName() {
return name;
}
#Override
#Column(length=2000)
public String getDescription() {
return description;
}
#Override
public void setName(String name) {
this.name=name;
}
#Override
public void setDescription(String desc) {
this.description=desc;
}
}
#Entity
#Table(name = "atfLabelText",
uniqueConstraints = #UniqueConstraint(columnNames = { "label_id", "tenant_id", "locale" }))
#SuppressWarnings("serial")
public class LabelText {
private long id;
private Label label;
private TenantImpl tenant;
private String locale;
private String text;
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
public long getId() {
return id;
}
#ManyToOne(optional = false)
#JoinColumn(name = "label_id", nullable = false, updatable = false)
public Label getLabel() {
return label;
}
public String getLocale() {
return locale;
}
#ManyToOne(optional = true, fetch = FetchType.LAZY)
#JoinColumn(name = "tenant_id", nullable = true, updatable = false)
public TenantImpl getTenant() {
return tenant;
}
#Column(length = 1500)
public String getText() {
return text;
}
public void setId(long id) {
this.id = id;
}
public void setLabel(Label label) {
this.label = label;
}
public void setLocale(String locale) {
this.locale = locale;
}
public void setTenant(TenantImpl tenant) {
this.tenant = tenant;
}
public void setText(String text) {
this.text = text;
}
}
could you please help me how to do delete functionality and ondelete cascade future.
Thanks
Vijaya Kumar
When you use CascadeType.DELETE:
#OneToMany(mappedBy="module")
#Cascade(CascadeType.DELETE)
private List<Label> label;
It tells Hibernate to navigate the label association and delete persistent instances when an object of ModuleImpl is passed to delete().
Again, if you want to delete any Label persistence instance when it is removed from the label association, you should go with all-delete-orphan:
#OneToMany(orphanRemoval = true, mappedBy = "module")
private List<Label> label;
With all-delete-orphan,any newly instantiated Label becomes persistent if the Label is referenced by a persistent Module. Any persistent Label will be deleted if it’s referenced by an Module when the Module is deleted. And also any persistent Label will be deleted if it’s removed from the label collection of a persistent Module.
I use Hibernate and
have two entities(City and Region) with OneToMany relation.
the First:
#Entity
#Table(name = "p_region")
public class Region implements Serializable{
#OneToMany(mappedBy = "region",fetch= FetchType.LAZY, cascade = CascadeType.MERGE)
private List<City> citys;
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Integer id;
private String name;
//++++++++++++++++++++ GETSET
public List<City> getCitys() {
return citys;
}
public void setCitys(List<City> citys) {
this.citys = citys;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
and the second one:
#Entity
#Table(name = "p_city")
public class City implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Integer id;
#NotEmpty(message = "Название не должно быть пустым")
#Length(max = 10, min = 2, message = "Название должно быть менее 2 символов и не
более 100")
private String cityName;
#NotEmpty(message = "Код города не должно быть пустым")
private String cityCode;
#Column(name = "zone")
private Integer zone;
#Basic(optional = true)
#Temporal(javax.persistence.TemporalType.TIMESTAMP)
private Date entryDate = Calendar.getInstance().getTime();
#ManyToOne()
private Region region;
#Basic(optional = true)
private String zip_code;
// GET SET ::::::::::::::::::::::::::::::::::
public Integer getZone() {
return zone;
}
public void setZone(Integer zone) {
this.zone = zone;
}
public Region getRegion() {
return region;
}
public void setRegion(Region region) {
this.region = region;
}
public void delete() {
System.out.println("QQQQQQQQQQQQQQQQQQQQQQ");
}
public String getCityCode() {
return cityCode;
}
public void setCityCode(String cityCode) {
this.cityCode = cityCode;
}
public String getCityName() {
return cityName;
}
public void setCityName(String cityName) {
this.cityName = cityName;
}
public Date getEntryDate() {
return entryDate;
}
public void setEntryDate(Date entryDate) {
this.entryDate = entryDate;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getZip_code() {
return zip_code;
}
public void setZip_code(String zip_code) {
this.zip_code = zip_code;
}
}
When I try to get simple Object(City) with JSON it returns the cycle:
{"id":577,"region":{"name":"нет региона","id":15,"citys":[{"id":577,"region":
{"name":"нет региона","id":15,"citys":[{"id":577,"region":{"name":"нет
региона","id":15,"citys":[{"id":577,"region":{"name":"нет
региона","id":15,"citys":[{"id":577,"region":{"name":"нет
региона","id":15,"citys":[{"id":577,"region":{"name":"нет
региона","id":15,"citys":[{"id":577,"region":{"name":"нет......so on.
Are there any solutions for this issue?
You need to break the bi-directional relationship between your entity before converting to JSON.
I think there are two options:
Iterate the child collection, e.g. citys in Region and set Region to null. This way, circular dependency would be broken. You my want to add one name mapped attribute regionId in the City so that relational info is still available.
Create another set of POJO objects without circular dependency, copy the values from Entity Objects and then get the JSON using POJO objects.