I`ve been trying to create a #ManyToMany relationship between two entities (team&contest) but when i try to post to the contest controller api i get a error 415 saying that
Failed to evaluate Jackson deserialization for type [[simple type, class com.project.Contest.Contest]]: com.fasterxml.jackson.databind.exc.InvalidDefinitionException: Cannot handle managed/back reference 'defaultReference': back reference type (`java.util.List<com.project.Contest.Contest>`) not compatible with managed type (com.project.Contest.Contest)
team :
#Getter
#Setter
#NoArgsConstructor
#AllArgsConstructor
#Entity
#Table(name = "team")
public class Team {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private long id;
#JsonBackReference
//#JsonIdentityInfo(generator = ObjectIdGenerators.PropertyGenerator.class , property = "id")
#ManyToMany(mappedBy = "teams", cascade = CascadeType.PERSIST)
private List<Contest> contests;
private String name;
private int wins, losses;
}
contest :
#Getter
#Setter
#NoArgsConstructor
#AllArgsConstructor
#Entity
#Table(name = "contest")
public class Contest {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private long id;
private String name;
#ManyToMany(cascade = CascadeType.PERSIST)
#JsonManagedReference
//#JsonIdentityInfo(generator = ObjectIdGenerators.PropertyGenerator.class , property = "id")
#JoinTable(
name = "team_contest",
inverseJoinColumns = #JoinColumn(name = "team_id"),
joinColumns = #JoinColumn( name = "contest_id")
)
private List<Team> teams;
#ManyToMany(cascade = CascadeType.PERSIST)
#JsonManagedReference
//#JsonIdentityInfo(generator = ObjectIdGenerators.PropertyGenerator.class , property = "id")
#JoinTable(
name = "contest_user",
joinColumns = #JoinColumn(name = "contest_id"),
inverseJoinColumns = #JoinColumn( name = "user_id")
)
private List<User> users;
}
i found out i can use #JsonIdentityInfo(generator = ObjectIdGenerators.PropertyGenerator.class , property = "id") instead of #JsonBackReference & #JsonManagedReference which helped me as it let me post to the database but then i refaced the problem that i can`t retrieve contest.teams[1] as because both objects have references to one another it creates some kind of an infinite loop as to get to the reference of the second object(contest.teams[1]) it needs to show the reference the contest.teams[0] has to the contest and soo forth. please help <3
This is the most famous bi-directional issue. To break up the loop while serialization, you can choose:
#JsonIgnore
#JsonIdentityInfo
JPA Projections
#EntityGraph
Or simply make the relationship uni-directional
thanks meridbt i was already using #JsonIdentityInfo but in the wrong place and i read a bit online and fixed my issue by doing this :
team :
#Getter
#Setter
#NoArgsConstructor
#AllArgsConstructor
#Entity
#Table(name = "team")
#JsonIdentityInfo(generator = ObjectIdGenerators.PropertyGenerator.class , property = "id")
public class Team {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private long id;
#ManyToMany(mappedBy = "teams", cascade = CascadeType.PERSIST)
private List<Contest> contests;
private String name;
private int wins, losses;
}
contest :
#Getter
#Setter
#NoArgsConstructor
#AllArgsConstructor
#Entity
#Table(name = "contest")
#JsonIdentityInfo(generator = ObjectIdGenerators.PropertyGenerator.class, property = "id")
public class Contest {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private long id;
private String name;
#ManyToMany(cascade = CascadeType.PERSIST)
#JoinTable(
name = "team_contest",
inverseJoinColumns = #JoinColumn(name = "team_id"),
joinColumns = #JoinColumn(name = "contest_id")
)
private List<Team> teams;
#ManyToMany(cascade = CascadeType.PERSIST)
#JoinTable(
name = "contest_user",
joinColumns = #JoinColumn(name = "contest_id"),
inverseJoinColumns = #JoinColumn(name = "user_id")
)
private List<User> users;
}
Related
Class Jobs has Many to One relationship with Profile.
When I retrieve through profileRepository.getByProfileId(id) the response returns recursive data.
Also if you notice Profile has Login object. I don't want to return that as well.
#Entity
#Table(name = "tbl_profile")
#Builder(toBuilder = true)
#NoArgsConstructor
#AllArgsConstructor
#Getter
public class Profile {
#Id
#Column(name = "profile_id")
#GeneratedValue(strategy = GenerationType.AUTO)
long profileId;
#NonNull
#Column(name = "name")
String name;
#Column(name = "description", nullable = false)
String description;
#OneToOne
#JoinColumn(name = "login_id",
referencedColumnName = "login_id")
Login login;
#OneToMany(
mappedBy = "profile"
)
List<Jobs> job;
Class Jobs
#Entity
#Table(name = "tbl_job")
#Builder(toBuilder = true)
#NoArgsConstructor
#AllArgsConstructor
#Getter
public class Jobs {
#Id
#Column(name = "job_id")
#GeneratedValue(strategy = GenerationType.AUTO)
long jobId;
#NonNull
#Column(name = "job_role", nullable = false)
String joRole;
#Column(name = "description", nullable = false)
String description;
#ManyToOne
#JoinColumn(name = "profile_id",
referencedColumnName = "profile_id")
Profile profile;
}
Use #JsonIgnore to the property to ignore the output on JSON. Also according to your business logic, recheck if you need bidirectional association. You could maybe add only unidirectional association.
I have 2 entities that relate to one another. These 2 entities should map to each other in a Many-To-Many relationship, however, I need to also have a timestamp of their respective relationship (when it happened), so I am trying to map them using an intermediary table.
Initially, the relationship was One-To-Many, but I realized that I actually need a Many-To-Many as the business logic requires this. The structure is still the same, as in there is a Parent-Child relationship, but this time, a child should have multiple parents as well.
My BaseEntity is an abstract class that contains the fields present in all the other entities:
#Data
#MappedSuperclass
public abstract class BaseEntity {
#Id
#Min(100)
#Max(Integer.MAX_VALUE)
#GeneratedValue(strategy = GenerationType.IDENTITY)
protected Long id;
#CreationTimestamp
#Column(name = "Created_At", updatable = false)
protected ZonedDateTime createdDate;
#UpdateTimestamp
#Column(name = "Updated_At")
protected ZonedDateTime updatedDate;
#NotNull
#Column(name = "Is_Active")
protected Boolean active = true;
}
Then I have my 2 entities that should relate in a Many-To-Many style. This is my first entity and should be the parent:
#Data
#Entity
#NoArgsConstructor
#AllArgsConstructor
#Table(name = "User")
#EqualsAndHashCode(callSuper = true)
#TypeDefs( {
#TypeDef(name = "json", typeClass = JsonStringType.class),
#TypeDef(name = "jsonb", typeClass = JsonBinaryType.class)
})
public class UserEntity extends BaseEntity {
#NotBlank
#Column(name = "User_Name", columnDefinition = "varchar(255) default 'N/A'")
private String userName;
#Nullable
#JoinColumn(name = "User_Id")
#OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY)
private List<UserRole> roleList = new ArrayList<>();
}
My second entity is considered the child entity:
#Data
#Entity
#NoArgsConstructor
#AllArgsConstructor
#Table(name = "Role")
#Where(clause = "is_active = true")
#EqualsAndHashCode(callSuper = true)
public class RoleEntity extends BaseEntity {
#NotBlank
#Column(name = "Name")
private String name;
#JsonIgnore
#JoinColumn(name = "Role_Id")
#OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY)
private List<UserRole> userList = new ArrayList<>();
}
I also have my intermediary entity:
#Data
#Entity
#Getter
#NoArgsConstructor
#AllArgsConstructor
#Where(clause = "is_active = true")
#EqualsAndHashCode(callSuper = true)
#Table(name = "User_Role", uniqueConstraints= #UniqueConstraint(columnNames={"User_Id", "Role_Id"}))
public class UserRole extends BaseEntity {
// Adding #JsonIgnore here will only cause an error
#JoinColumn(name = "User_Id")
#ManyToOne(cascade = CascadeType.ALL, fetch = FetchType.LAZY, optional = false, targetEntity = UserEntity.class)
private UserEntity user;
#JoinColumn(name = "Role_Id")
#ManyToOne(cascade = CascadeType.ALL, fetch = FetchType.LAZY, optional = false, targetEntity = RoleEntity.class)
private RoleEntity role;
}
Problem now is that when I try to get my UserEntity, I get infinite recursion.
So far I've tried using #JsonIgnore, #JsonManagedReference, #JsonBackReference and it did not work or I simply don't know where or how to use them properly.
Recap:
2 entities mapped by Many-To-Many relationship;
Many-To-Many implemented using an intermediary entity and One-To-Many + Many-To-One associations;
Getting recursion when showing my UserEntity;
Update: I managed to get this fixed using a different approach described in my answer to this question.
I fixed this by implementing a Composite Key structure and just using the #JsonIgnore annotation:
#Getter
#Setter
#Embeddable
#EqualsAndHashCode
#NoArgsConstructor
#AllArgsConstructor
public class UserRoleKey implements Serializable {
#Column(name = "User_Id")
Long userId;
#Column(name = "Role_Id")
Long roleId;
}
This gets to be used in the intermediary entity, which now doesn't use my BaseEntity anymore.
#Data
#Entity
#NoArgsConstructor
#AllArgsConstructor
#Table(name = "User_Role", uniqueConstraints= #UniqueConstraint(columnNames={"User_Id", "Role_Id"}))
public class UserRole {
#JsonIgnore
#EmbeddedId
private UserRoleKey id;
#JsonIgnore
#MapsId("userId")
#JoinColumn(name = "User_Id")
#ManyToOne(optional = false, targetEntity = UserEntity.class)
private UserEntity user;
#MapsId("roleId")
#JoinColumn(name = "Role_Id")
#ManyToOne(optional = false, targetEntity = RoleEntity.class)
private RoleEntity role;
#CreationTimestamp
#Column(name = "Created_At", updatable = false)
private ZonedDateTime createdDate;
}
Now, for my two entities, I have this definition:
UserEntity class (definition of the role):
#Nullable
#OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "user", orphanRemoval = true)
private List<UserRole> roleList = new ArrayList<>();
RoleEntity class (definition of the user)
#Nullable
#JsonIgnore
#OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "role", orphanRemoval = true)
private List<UserRole> userList = new ArrayList<>();
This seems to be working and no longer returns an infinite JSON recursion.
I have an app with Angular front end and Spring backend. The two classes in question here are (backend):
#Setter
#Getter
#AllArgsConstructor
#NoArgsConstructor
#Entity
#Table(name = "tournament_games")
#JsonIdentityInfo(generator = ObjectIdGenerators.PropertyGenerator.class, property = "id")
public class TournamentGame {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "id")
private Long id;
#ManyToOne(fetch = FetchType.EAGER, optional = false)
#JoinColumn(name = "code", foreignKey = #ForeignKey(name = "code_fk"))
private TournamentCode code;
#ManyToOne(fetch = FetchType.EAGER, optional = false)
#JoinColumn(name = "type", foreignKey = #ForeignKey(name = "game_type_fk"))
private GameType type;
#Column(name = "home_score")
private int home_score;
#Column(name = "away_score")
private int away_score;
#ManyToOne(fetch = FetchType.EAGER, optional = false)
#JoinColumn(name = "result_type", foreignKey = #ForeignKey(name = "result_type_fk"))
private ResultType result_type;
#Column(name = "status")
private boolean status;
#Column(name = "round")
private int round;
#Column(name = "locked")
private boolean locked;
#OneToMany(mappedBy = "game", fetch = FetchType.EAGER)
private List<TournamentGamesPlayers> players = new ArrayList<>();
}
and
#Setter
#Getter
#AllArgsConstructor
#NoArgsConstructor
#Entity
#Table(name = "tournament_games_players")
#JsonIdentityInfo(generator = ObjectIdGenerators.PropertyGenerator.class, property = "game")
public class TournamentGamesPlayers implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#ManyToOne
#JoinColumn(name = "tournament_game_id")
private TournamentGame game;
#Id
#ManyToOne
#JoinColumn(name = "playerid")
private Player player;
#Column(name = "home")
private boolean home;
}
I need help figuring out how to persist the List<TournamentGamesPlayers> when I save and/or update a TournamentGame object. I generate 45 games. The first 30 games have known players, and so I set them before saving. The last 15 do not have entries for the TournamentGamesPlayers join table, because I need to add them later.
I am able to get some results with CascadeType.ALL on the #OneToMany side when I initially generate the games, but it fails when I try to update a game with a seemingly infinite recursion/stack overflow.
If I omit any cascade type, the games side get generated, but the join table #ManyToOne side does not get entered.
I ended up just putting the players back into the game table to make my life easier.
try putting CascadeType.MERGE, CascadeType.ALL "delete parent and orphans" (JPA CascadeType.ALL does not delete orphans).
Also, defining the relationship as EAGER and not ignoring the JSON property can have problems. I would add #JsonIgnore to one of the parts of the relationship
I have three tables:
1) book: id (primary), name
2) shop: code (unique, not primary), name
3) book_shop: book_id, shop_id (code), price
I want to get shops in book like
book.getShop();
How to link this entities?
I tried:
#Data
#NoArgsConstructor
#Entity
#Table(name = "book", schema = "example")
#EntityListeners(AuditingEntityListener.class)
public class Book {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;
private String name;
#OneToMany(mappedBy = "book", cascade = CascadeType.ALL, orphanRemoval = true)
private Set<BookShop> bookShop;
}
.
#Data
#NoArgsConstructor
#Entity
#Table(name = "shop", schema = "example")
#EntityListeners(AuditingEntityListener.class)
public class Shop {
#Id
private int code;
private String name;
#OneToMany(mappedBy = "shop", cascade = CascadeType.ALL, orphanRemoval = true)
private Set<BookShop> bookShop;
}
.
#Data
#NoArgsConstructor
#Entity
#Table(name = "book_shop", schema = "example")
public class BookShop implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;
#Id
#ManyToOne
#JoinColumn(name = "book_id")
private Book book;
#Id
#ManyToOne
#JoinColumn(name = "shop_id")
private Shop shop;
#Column(name = "price")
private int fromDate;
}
This code return empty set: Book book = bookRepostiory.getById(1).get().getBookShop()
Try the many to many mapping implement like as below remove your book_shop table,
add this code to shop entity,
#ManyToMany(fetch = FetchType.EAGER, cascade = CascadeType.PERSIST)
#JoinTable(name = "book_shop",
joinColumns = {#JoinColumn(name = "book_id", nullable = false)},
inverseJoinColumns = {#JoinColumn(name = "shop_id", nullable = false)})
private Set<Book> bookList = null;
add this code to book entity,
#ManyToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL,
mappedBy ="bookList")
private Set<Shop> shopList=null;
if any issue inform!!
I would suggest, first - initialize the set in the entity
private Set<BookShop> bookShop = new HashSet<>();
Second, add fetch = FetchType.EAGER to your association, for e.g.
#OneToMany(fetch = FetchType.EAGER, mappedBy = "book", cascade = CascadeType.ALL)
I'm very new to this topic so i followed a tutorial. after following steps i got some build time errors.
I have imported javax persistence like this.
import javax.persistence.*;
Then the student model class
#Entity
#Table(name="STUDENT")
public class Student {
#Id
#GeneratedValue
private Integer studentId;
#ManyToOne(cascade = CascadeType.ALL)
#JoinTable(name="Enrollment", joinColumns = {#JoinColumns(name="student_id")},
inverseJoinColumns = {#JoinColumns(name="course_id")})
private List<Course> courses = new ArrayList<>();
}
The Course model class.
#Entity
#Table(name="COURSE")
public class Course {
#GeneratedValue
private Integer id;
#ManyToMany(mappedBy ="courses")
private List<Student> students = new ArrayList<>();
These are set of errors that i have got
incompatible types: javax.persistence.JoinColumns cannot be converted to javax.persistence.JoinColumn
cannot find symbol
symbol: method name()
location: #interface javax.persistence.JoinColumns
annotation #javax.persistence.JoinColumns is missing a default value for the element 'value'
Can anyone help me to get rid of this issues?
Thanks.
A #JoinTable annotation really has a joinColumns parameter, but the syntax you had used is not correct. If tables are joined by only column and inverse column you shouldn't use a #JoinColumns annotation. You have to change it in the following way:
#Entity
#Table(name="STUDENT")
public class Student {
#Id
#GeneratedValue
private Integer studentId;
#ManyToOne(cascade = CascadeType.ALL)
#JoinTable(
name="Enrollment",
joinColumns = #JoinColumn(name="student_id", referencedColumnName = "id"),
inverseJoinColumns = #JoinColumn(name="course_id", referencedColumnName = "id"))
private List<Course> courses = new ArrayList<>();
}
and only if joining goes by more then one column you have to do something like this:
#Entity
#Table(name="STUDENT")
public class Student {
#Id
#GeneratedValue
private Integer studentId;
#ManyToOne(cascade = CascadeType.ALL)
#JoinTable(
name="Enrollment",
joinColumns = #JoinColumns{
#JoinColumn(name="student_id", referencedColumnName = "id"),
#JoinColumn(name="another_id", referencedColumnName = "another_id")
},
inverseJoinColumns = #JoinColumn(name="course_id", referencedColumnName = "id"))
private List<Course> courses = new ArrayList<>();
}
Hope it will help