Jpa bidirectional one-to-one Association

Jpa bidirectional one-to-one Association
1.1. Relationship maintainer

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 association configuration * If mappedBy is not configured, optional is configured on the Link maintenance end *, the foreign key cannot be blank, the other side cannot be empty. You do not need to configure */@ OneToOne (cascade = CascadeType. 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. Link maintainer

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;/*** mappedBy = "idCard" is specified as the link maintainer */@ OneToOne (cascade = {CascadeType. PERSIST, CascadeType. MERGE}, fetch = FetchType. EAGER, mappedBy = "idCard") private Person 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;} public Person getPerson () {return person;} public void setPerson (Person person) {this. person = person ;}}

1.3. Test

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.createEntityManagerFactory("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(); } }