Hibernate 菜鸟教程 10 组成关系

GitHub

组成关系

在一个员工模型里面需要存入
员工公司所在地址的城市，街道
员工籍贯所在的城市，街道，
此时可以抽取城市，街道变成一个模型即是组成关系

模型对象Employee

public class Employee {  private Long id;  private String name;  // 公司的地址  private Address comAddress;  // 籍贯所在地  private Address homeAddress;

映射文件Employee.hbm.xml

<class name="Employee" table="t_employee">        <id name="id">            <generator class="native" />        </id>        <property name="name" />        <!-- 组成关系:以对象的方式来解决重复的信息 -->        <!-- 公司所在的地址 -->        <!-- class必须配置为全类名 -->        <component name="comAddress" class="Address">            <!-- property:name必须配置成java的属性，column配置成数据库的字段，而且不能重复 -->            <property name="city" column="com_city" />            <property name="street" column="com_street" />        </component>        <!-- 籍贯所在的地址 -->        <component name="homeAddress" class="Address">            <property name="city" column="home_city" />            <property name="street" column="home_street" />        </component>    </class>

测试对象MainTest

public class MainTest {  Session session = null;  @Before  public void save() {    session = HibernateUtils.INSTANCE.getSession();    session.beginTransaction();    Address comAddress = new Address("bj", "st1");    Address homeAddress = new Address("sh", "st2");    Employee employee = new Employee("user");    employee.setComAddress(comAddress);    employee.setHomeAddress(homeAddress);    session.save(employee);  }  @Test  public void get() throws Exception {    Employee employee = (Employee) session.get(Employee.class, 1L);    System.out.println(employee);    System.out.println(employee.getComAddress());    System.out.println(employee.getHomeAddress());  }  @After  public void colse() {    session.getTransaction().commit();    session.close();  }}

源码地址

https://github.com/je-ge/hibernate

如果觉得我的文章或者代码对您有帮助,可以请我喝杯咖啡。
您的支持将鼓励我继续创作!谢谢！