8.1.2 Hibernate：一对一双向关联（bidirectional）

本文主要是介绍8.1.2 Hibernate：一对一双向关联（bidirectional），希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

1 定义映射类
1.1 表 phone 的映射类定义：

package hibernate;import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.OneToOne;
import javax.persistence.Table;@Entity
@Table(name = "phone")
public class Phone {@Id@GeneratedValue(strategy = GenerationType.IDENTITY)@Column(name = "id")private int id;@Column(name = "imei")private String imei;@Column(name = "number")private String number;@OneToOne(mappedBy = "phone", orphanRemoval = true, cascade = CascadeType.ALL, fetch = FetchType.EAGER)private PhoneDetail phoneDetail;public Phone() {}public Phone(String imei, String number) {this.imei = imei;this.number = number;}// 省略 Getters 和 Setters ...}

1.2 表 phone_detail 的映射类定义：

package hibernate;import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.OneToOne;
import javax.persistence.Table;@Entity
@Table(name = "phone_detail")
public class PhoneDetail {@Id@GeneratedValue(strategy = GenerationType.IDENTITY)@Column(name = "id")private int id;@Column(name = "manufacturer")private String manufacturer;@Column(name = "model")private String model;@OneToOne(cascade = CascadeType.ALL, fetch = FetchType.EAGER)@JoinColumn(name = "phone_id")private Phone phone;public PhoneDetail() {}public PhoneDetail(String manufacturer, String model) {this.manufacturer = manufacturer;this.model = model;}// 省略 Getters 和 Setters ...}

2 测试
2.1 新增

@Test
public void test() {Configuration configuration = new Configuration().configure("hibernate.cfg.xml");SessionFactory sessionFactory = configuration.buildSessionFactory();Session session = sessionFactory.openSession();Transaction transaction = session.beginTransaction();Phone phone = new Phone("812345678912345", "18012345678");PhoneDetail phoneDetail = new PhoneDetail("XXX", "XXX-2017");phone.setPhoneDetail(phoneDetail);phoneDetail.setPhone(phone);session.save(phone);transaction.commit();session.close();sessionFactory.close();
}

运行测试，数据库表 phone 和 phone_detail 中新插入了两条数据（日志省略）。

将单元测试中 session.save(phone); 替换成 session.save(phoneDetail);，测试结果相同。

由此可见，双向关联的任一方都维护级联关系。

2.2 删除
基于以上测试新增的数据进行删除测试。

@Test
public void test() {Configuration configuration = new Configuration().configure("hibernate.cfg.xml");SessionFactory sessionFactory = configuration.buildSessionFactory();Session session = sessionFactory.openSession();Transaction transaction = session.beginTransaction();Phone phone = (Phone) session.createQuery(" FROM Phone").list().get(0);session.delete(phone);transaction.commit();session.close();sessionFactory.close();
}

运行测试，数据库表 phone 和 phone_detail 中对应记录被删除（日志省略）。

将单元测试中

Phone phone = (Phone) session.createQuery(" FROM Phone").list().get(0);
session.delete(phone);

替换成

PhoneDetail phoneDetail = (PhoneDetail) session.createQuery(" FROM PhoneDetail").list().get(0);
session.delete(phoneDetail);

测试结果相同。

2.3 更新
基于新增测试的数据进行更新测试。
2.3.1 通过 Phone 查找关联的 PhoneDetail 并执行级联更新

@Test
public void test() {Configuration configuration = new Configuration().configure("hibernate.cfg.xml");SessionFactory sessionFactory = configuration.buildSessionFactory();Session session = sessionFactory.openSession();Transaction transaction = session.beginTransaction();Phone phone = (Phone) session.createQuery(" FROM Phone").list().get(0);phone.setImei("898765432198765");phone.setNumber("17712345678");PhoneDetail phoneDetail = phone.getPhoneDetail();phoneDetail.setManufacturer("YYY");phoneDetail.setModel("YYY-2017");session.save(phone);transaction.commit();session.close();sessionFactory.close();
}

运行测试，数据库表 phone 和 phone_detail 中对应记录级联更新成功（日志省略）。

将单元测试中 session.save(phone); 替换成 session.save(phoneDetail);，测试结果相同，同样级联更新成功。

2.3.1 通过 PhoneDetail 查找关联的 Phone 并执行级联更新

@Test
public void test() {Configuration configuration = new Configuration().configure("hibernate.cfg.xml");SessionFactory sessionFactory = configuration.buildSessionFactory();Session session = sessionFactory.openSession();Transaction transaction = session.beginTransaction();PhoneDetail phoneDetail = (PhoneDetail) session.createQuery(" FROM PhoneDetail").list().get(0);phoneDetail.setManufacturer("YYY");phoneDetail.setModel("YYY-2017");Phone phone = phoneDetail.getPhone();phone.setImei("898765432198765");phone.setNumber("17712345678");session.save(phoneDetail);transaction.commit();session.close();sessionFactory.close();
}

运行测试，数据库表 phone 和 phone_detail 中对应记录级联更新成功（日志省略）。

将单元测试中 session.save(phoneDetail); 替换成 session.save(phone);，测试结果相同，同样级联更新成功。

2.4 查询
基于新增测试的数据进行查询测试。

@Test
public void test() {Configuration configuration = new Configuration().configure("hibernate.cfg.xml");SessionFactory sessionFactory = configuration.buildSessionFactory();Session session = sessionFactory.openSession();Transaction transaction = session.beginTransaction();Phone phone = (Phone) session.createQuery(" FROM Phone").list().get(0);System.out.println("-------------------- From Phone --------------------");System.out.println("Phone ID : " + phone.getId());System.out.println("Phone IMEI : " + phone.getImei());System.out.println("Phone Number : " + phone.getNumber());System.out.println("Binded Phone Detail ID : " + phone.getPhoneDetail().getId());System.out.println("Binded Phone Detail Manufacture : " + phone.getPhoneDetail().getManufacturer());System.out.println("Binded Phone Detail Model : " + phone.getPhoneDetail().getModel());System.out.println("----------------------------------------------");PhoneDetail phoneDetail = (PhoneDetail) session.createQuery(" FROM PhoneDetail").list().get(0);System.out.println("-------------------- From Phone Detail --------------------");System.out.println("Phone Detail ID : " + phoneDetail.getId());System.out.println("Phone Detail Manufacture : " + phoneDetail.getManufacturer());System.out.println("Phone Detail Model : " + phoneDetail.getModel());System.out.println("Binded Phone ID : " + phoneDetail.getPhone().getId());System.out.println("Binded Phone IMEI : " + phoneDetail.getPhone().getImei());System.out.println("Binded Phone Number : " + phoneDetail.getPhone().getNumber());System.out.println("----------------------------------------------");transaction.commit();session.close();sessionFactory.close();
}

运行测试，打印结果：

......
-------------------- From Phone --------------------
Phone ID : 15
Phone IMEI : 898765432198765
Phone Number : 17712345678
Binded Phone Detail ID : 11
Binded Phone Detail Manufacture : YYY
Binded Phone Detail Model : YYY-2017
----------------------------------------------
......
-------------------- From Phone Detail --------------------
Phone Detail ID : 11
Phone Detail Manufacture : YYY
Phone Detail Model : YYY-2017
Binded Phone ID : 15
Binded Phone IMEI : 898765432198765
Binded Phone Number : 17712345678
----------------------------------------------
......

这篇关于8.1.2 Hibernate：一对一双向关联（bidirectional）的文章就介绍到这儿，希望我们推荐的文章对编程师们有所帮助！

---