Issue
i am currently building an Application with Spring and i have a Question there:
I want to have an Entity Address which looks like this:
@Entity(name = "Address")
@Table(name = "address")
@EntityListeners(AuditingEntityListener.class)
public class Address {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "id")
private Long id;
@Column(name = "city")
private String city;
@Column(name = "country")
private String country;
@Column(name = "postalcode")
private String postalCode;
@Column(name = "state")
private String state;
@Column(name = "street")
private String street;
public Address() {
}
}
I want to use this Address Entity in multiple Entities, for example in the User or Order Entity. Later, i will like to have many Entities which need an Address. But i don't want to specify each Relation in the Address Entity, otherwise it will get to complex. Is it possible to have a Link from the User to the Address with only specifying this Link in the User Entity?
My User Entity looks something like this:
@Entity(name = "User")
@Table(name = "User")
@EntityListeners(AuditingEntityListener.class)
public class User {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "id")
private Long id;
@Column(name = "username")
private String userName;
@OneToOne(
mappedBy = "address",
orphanRemoval = true,
cascade = {
CascadeType.PERSIST,
CascadeType.REMOVE
}
)
private Address billingAddress;
public User() {
}
}
Solution
Yes, it is possible, but you don't actually need mappedBy property, otherwise you are telling JPA to search for a address property in the other side of the relationship (that you actually want to be unidirectional):
@Entity(name = "User")
@Table(name = "User")
@EntityListeners(AuditingEntityListener.class)
public class User {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "id")
private Long id;
@Column(name = "username")
private String userName;
@OneToOne(
orphanRemoval = true,
cascade = { CascadeType.PERSIST, CascadeType.REMOVE }
)
private Address billingAddress;
public User() {
}
}
You can read more about this in the following online resources:
- https://docs.oracle.com/javaee/6/api/javax/persistence/OneToOne.html
- https://www.baeldung.com/jpa-one-to-one
- https://javabydeveloper.com/one-one-unidirectional-association/
Answered By - João Dias
