JPA视频学习（四）双向一对一关联配置

1.persistence.xml配置：

<?xml version="1.0" encoding="UTF-8"?>
<persistence xmlns="http://java.sun.com/xml/ns/persistence"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/persistence
    http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd" version="1.0">
    
	<persistence-unit name="JPAOneToOnePU" transaction-type="RESOURCE_LOCAL">
		<provider>org.hibernate.ejb.HibernatePersistence</provider>
  		<properties>
  		    <property name="hibernate.dialect" value="org.hibernate.dialect.MySQL5Dialect"/>
			<property name = "hibernate.connection.driver_class" value = "com.mysql.jdbc.Driver"/>
			<property name = "hibernate.connection.url" value = "jdbc:mysql://localhost:3306/jpa?useUnicode=true&amp;characterEncoding=UTF-8"/>
			<property name = "hibernate.connection.username" value = "root"/>
			<property name="hibernate.max_fetch_depth" value="3"/>
            <property name="hibernate.hbm2ddl.auto" value="update"/>  
	  	</properties>
	</persistence-unit>
  
</persistence>

2.实体bean的配置:

people实体：

import javax.persistence.Basic;
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 People {
  private Integer id;
  private String name;
  private IDCard idcard;
  
  
  public People(){
	  
  }
  
  public People(String name){
	  this.name=name;
  }
    @Id
	@GeneratedValue
	public Integer getId() {
		return id;
	}

	public void setId(Integer id) {
		this.id = id;
	}

	@Column(length = 10, nullable = false)
	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	@OneToOne(optional=false,cascade=CascadeType.ALL)
	@JoinColumn(name="idcard_id")//指定外键名称
	public IDCard getIdcard() {
		return idcard;
	}

	public void setIdcard(IDCard idcard) {
		this.idcard = idcard;
	}
	
	
  
  
}

IDCard实体：

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 Integer id;
	private String cardno;
	private People people;
	
	
	public IDCard(){}
	
	public IDCard(String cardno){
		this.cardno=cardno;
	}
	@Id @GeneratedValue
	public Integer getId() {
		return id;
	}
	public void setId(Integer id) {
		this.id = id;
	}
	
	@Column(length=18,nullable=false)
	public String getCardno() {
		return cardno;
	}
	public void setCardno(String cardno) {
		this.cardno = cardno;
	}
	
	@OneToOne(mappedBy="idcard",cascade={CascadeType.PERSIST
			 ,CascadeType.MERGE,CascadeType.REFRESH}
	         ,optional=false)//指定为关系的被维护端,这里的optional可以去掉，因为外键不允许为空
	public People getPeople() {
		return people;
	}
	public void setPeople(People people) {
		this.people = people;
	}
	
	
	
	
}

3.Junit测试：

package junit.test;


import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;

import org.junit.BeforeClass;
import org.junit.Test;

import com.persia.bean.IDCard;
import com.persia.bean.People;

public class OneToOneTest {

	@BeforeClass
	public static void setUpBeforeClass() throws Exception {
	}

	//@Test
	public void save(){
		EntityManagerFactory factory=Persistence.createEntityManagerFactory("JPAOneToOnePU");
	    EntityManager eManager=factory.createEntityManager();
	    eManager.getTransaction().begin();
	      
	       People people=new People("一对一");
	       IDCard card=new IDCard("123466789");
	       people.setIdcard(card);
	       card.setPeople(people);
	       eManager.persist(people);
	       
	    eManager.getTransaction().commit();
	    eManager.close();
		factory.close();
	}
	
	//@Test
	public void getPeople(){
		EntityManagerFactory factory=Persistence.createEntityManagerFactory("JPAOneToOnePU");
	    EntityManager eManager=factory.createEntityManager();
	   	 People people=eManager.find(People.class, 1);
	   	 System.out.println(people.getName()+"idcard:"+people.getIdcard().getCardno());
	    
	    eManager.close();
		factory.close();
	}
	
	//@Test
	public void updatePeople(){
		EntityManagerFactory factory=Persistence.createEntityManagerFactory("JPAOneToOnePU");
	    EntityManager eManager=factory.createEntityManager();
	    eManager.getTransaction().begin();
	      
	       People people=eManager.find(People.class, 1);
	       people.setName("sky");
	       people.getIdcard().setCardno("987654321");
	       eManager.merge(people);
	   
	    eManager.getTransaction().commit();
	    eManager.close();
		factory.close();
	}
	
	@Test
	public void deletePeople(){
		EntityManagerFactory factory=Persistence.createEntityManagerFactory("JPAOneToOnePU");
	    EntityManager eManager=factory.createEntityManager();
	    eManager.getTransaction().begin();
	      
	       People people=eManager.find(People.class, 1);
	       eManager.remove(people);
	   
	    eManager.getTransaction().commit();
	    eManager.close();
		factory.close();
	}
}