Hibernate入门到精通-关系映射多对一

2.多对一 many-to-one

多个address对应一个user

1.address.java

public class Address {    private Long id;    private String name;    private User user;     //省略了getters/setters/constructs/toString}

address.hbm.xml

<!DOCTYPE hibernate-mapping PUBLIC        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"        "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">​<hibernate-mapping>    <!--        name:类名        table:表名     -->    <class name="com.qfedu.entity.Address" table="address">        <!-- 主键 -->        <id name="id" column="id">            <generator class="native"></generator>        </id>        <!-- 其他属性 -->        <property name="name" column="name"></property>        <!--定义多对一-->        <many-to-one name="user" class="com.qfedu.entity.User" column="user_id"></many-to-one>    </class></hibernate-mapping>

2.user.java

public class User {    private Long id;    private String name;    private int age;    //省略了getters/setters/constructs/toString}

user.hbm.xml

<!DOCTYPE hibernate-mapping PUBLIC        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"        "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">​<hibernate-mapping>​    <!--        name:类名        table:表名     -->    <class name="com.qfedu.entity.User" table="user">        <!-- 主键 -->        <id name="id" column="id">            <generator class="native"></generator>        </id>        <!-- 其他属性 -->        <property name="name" column="name"></property>        <property name="age" column="age"></property>​    </class></hibernate-mapping>

3.测试：

public static void main( String[] args ){    //1.创建sessionFactory对象    SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();​    //2.创建session对象    Session session= sessionFactory.openSession();​    //3.开启事务    Transaction tx = session.beginTransaction();​    //4.执行    User u = new User();    u.setName("zhangsan1");    u.setAge(18);​    Address ad1= new Address();    ad1.setName("beijing");    ad1.setUser(u);​    Address ad2= new Address();    ad2.setName("qingdao");    ad2.setUser(u);​    session.save(ad1);    session.save(ad2);    session.save(u);​    //5.提交事务    tx.commit();​    //6.关闭session    session.close();    sessionFactory.close();}