JPA bidirectional one-to-one correlation relationship

1.1. Relationship Maintenance Party

Person.java

Package com.morris.entity; Import Javax.persistence.cascadetype;import Javax.persistence.column;import Javax.persistence.entity;import Javax.persistence.fetchtype;import Javax.persistence.generatedvalue;import Javax.persistence.id;import Javax.persistence.joincolumn;import Javax.persistence.onetoone;import javax.persistence.Table; @Entity @table (name= "persons") public class Person {@Id @GeneratedValue private Integer personId; @Column (name= "Person_name", Length=50,nullable=false) private String personname; /** * One-to-one affinity configuration * No configuration Mappedby is configured for the relationship maintenance side * Optional Description foreign key cannot be empty, also cannot be empty on the other side, do not need to configure the */@OneToOne (CASCADE=CA Scadetype.all,fetch=fetchtype.eager,optional=false) @JoinColumn (name= "card_id") private Idcard Idcard; Public Integer Getpersonid () {return personId; } public void Setpersonid (Integer personId) {This.personid = PersonId; } public String Getpersonname () {return personname; } public void SETpersonname (String personname) {this.personname = PersonName; } public Idcard Getidcard () {return idcard; } public void Setidcard (Idcard idcard) {this.idcard = Idcard; } Public person (Integer personId, String personname, Idcard Idcard) {super (); This.personid = personId; This.personname = PersonName; This.idcard = Idcard; } public person () {super (); TODO auto-generated Constructor stub} @Override public String toString () {return ' person [personid= '] + PersonId + ", personname=" + PersonName + ", idcard=" + Idcard + "]"; } Public person (String PersonName) {super (); This.personname = PersonName; }}

1.2. Relationship maintained by the party

Idcard.java

Package com.morris.entity; Import Javax.persistence.cascadetype;import Javax.persistence.column;import Javax.persistence.entity;import Javax.persistence.fetchtype;import Javax.persistence.generatedvalue;import Javax.persistence.id;import Javax.persistence.onetoone;import javax.persistence.Table; @Entity @table (name= "Id_card") public class Idcard {@Id @GeneratedValue private Integer cardId; @Column (name= "Card_no", Length=18,nullable=false) private String Cardno; /** * Specifies that mappedby= "Idcard" is the relationship-maintained party/@OneToOne (Cascade={cascadetype.persist,cascadetype.merge},fetch=fetchtyp E.eager,mappedby= "Idcard") private person person; Public Idcard (String Cardno) {super (); This.cardno = Cardno; } public Idcard () {super (); TODO auto-generated Constructor stub} public Idcard (String Cardno, person person) {super (); This.cardno = Cardno; This.person = person; } @Override Public String TostriNg () {return "Idcard [cardid=" + CardId + ", cardno=" + Cardno + ", person=" + person + "]"; } public Integer Getcardid () {return cardId; } public void Setcardid (Integer cardId) {this.cardid = CardId; } public String Getcardno () {return cardno; } public void Setcardno (String cardno) {this.cardno = Cardno; Getperson () {return person; } public void Setperson (person person) {This.person = person; } }

1.3. Testing

One2onetest.java

Package com.morris.test; Import Javax.persistence.entitymanager;import Javax.persistence.entitymanagerfactory;import Javax.persistence.Persistence; Import Org.junit.afterclass;import Org.junit.beforeclass;import org.junit.Test; Import Com.morris.entity.IDCard; Import Com.morris.entity.Person; public class One2onetest {private static entitymanagerfactory factory; private static Entitymanager manager; @BeforeClass public static void Setupbeforeclass () throws Exception {factory = Persistence.createentityman Agerfactory ("Jpademo"); Manager = Factory.createentitymanager (); Manager.gettransaction (). Begin (); @Test public void Test () {Person person = new Person ("Morris"); Idcard card = new Idcard ("123456789"); Person.setidcard (card); Manager.persist (person); } @AfterClass public static void Setupafterclass () throws Exception {manager.gettransaction (). cOmmit (); Manager.close (); Factory.close (); } }

JPA bidirectional one-to-one correlation relationship