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Adrian Matei for Codever

Posted on • Updated on • Originally published at codever.dev

How to find an entity in jpa with primary key

Use the find method of the EntityManager, where the primary key is provided as the second parameter:

@Stateless
public class PartnerRepository {

  @Inject private EntityManager em;

  public Optional<Partner> find(String partnerNumber) {
    return Optional.ofNullable(em.find(Partner.class, partnerNumber));
  }
}
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The entity looks something like the following, with partnerNumber as primary key:

@Entity
@Access(AccessType.FIELD)
@Table(name = "T_PARTNER")
public class Partner {

  @Id
  @NotNull
  @Column(name = "PARTNER_NUMBER", nullable = false)
  private Integer partnerNumer;

  //other fields ignored for readability
}
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