package learn.jpa.entity;

import javax.persistence.CascadeType;

import javax.persistence.Column;

import javax.persistence.Entity;

import javax.persistence.GeneratedValue;

import javax.persistence.Id;

import javax.persistence.JoinColumn;

import javax.persistence.OneToOne;

@Entity

public class Person {

    private int id;

    private String name;

    private IDCard idcard;

    public Person(){

    }

    public Person(String name){

        this.name = name;

    }

    @OneToOne(optional=false,cascade=CascadeType.ALL)

    @JoinColumn(name="idcard_id")

    public IDCard getIdcard() {

        return idcard;

    }

    public void setIdcard(IDCard idcard) {

        this.idcard = idcard;

    }

    @Id

    @GeneratedValue

    public int getId() {

        return id;

    }

    public void setId(int id) {

        this.id = id;

    }

    @Column(length=10,nullable=false)

    public String getName() {

        return name;

    }

    public void setName(String name) {

        this.name = name;

    }

}

package learn.jpa.entity;

import javax.persistence.CascadeType;

import javax.persistence.Column;

import javax.persistence.Entity;

import javax.persistence.GeneratedValue;

import javax.persistence.Id;

import javax.persistence.OneToOne;

@Entity

public class IDCard {

    private int id;

    private String cardno;

    private Person person;

    public IDCard(){

    }

    public IDCard(String cardno){

        this.cardno = cardno;

    }

    @OneToOne(mappedBy="idcard",cascade={CascadeType.PERSIST,CascadeType.MERGE,CascadeType.REFRESH},

            optional=false)

    public Person getPerson() {

        return person;

    }

    public void setPerson(Person person) {

        this.person = person;

    }

    @Id

    @GeneratedValue

    public int getId() {

        return id;

    }

    public void setId(int id) {

        this.id = id;

    }

    @Column(length=18, nullable=false)

    public String getCardno() {

        return cardno;

    }

    public void setCardno(String cardno) {

        this.cardno = cardno;

    }

}

package learn.jpa.test;

import static org.junit.Assert.*;

import javax.persistence.EntityManager;

import javax.persistence.EntityManagerFactory;

import javax.persistence.Persistence;

import learn.jpa.entity.IDCard;

import learn.jpa.entity.Person;

import org.junit.Test;

public class OneToOneTest {

    /**

     * 测试数据库是否可以生成表

     */

    @Test

    public void test() {

        EntityManagerFactory factory = Persistence.createEntityManagerFactory("learn_jpa");

        factory.close();

    }

    @Test

    public void save(){

        EntityManagerFactory factory = Persistence.createEntityManagerFactory("learn_jpa");

        EntityManager em = factory.createEntityManager();

        em.getTransaction().begin();   // 开启事务

        Person person = new Person("hwl");

        IDCard idcard = new IDCard("435034189809170123");

        idcard.setPerson(person);

        person.setIdcard(idcard);

        em.persist(person);

        em.getTransaction().commit();

        em.close();

        factory.close();

    }

}