Hibernate 多对多单向关联

Hibernate 多对多单向关联
 
一、模型介绍
 
多个人（Person）对应多个地址（Address）。
一个人可对应多个地址，一个地址也可以对应多个人。 
二、实体（省略getter、setter方法）
 
public class Personnn {
    private int personid;
    private String name;
    private int age;
    private Set addresses=new HashSet();
 
public class Addressnn {
    private int addressid;
    private String addressdetail;
 
三、表模型
 
person_nn;
+----------+--------------+------+-----+---------+----------------+
| Field    | Type         | Null | Key | Default | Extra          |
+----------+--------------+------+-----+---------+----------------+
| personid | int(11)      | NO   | PRI | NULL    | auto_increment |
| name     | varchar(255) | YES  |     | NULL    |                |
| age      | int(11)      | YES  |     | NULL    |                |
+----------+--------------+------+-----+---------+----------------+
 
join_nn;
+-----------+---------+------+-----+---------+-------+
| Field     | Type    | Null | Key | Default | Extra |
+-----------+---------+------+-----+---------+-------+
| personid  | int(11) | NO   | PRI |         |       |
| addressid | int(11) | NO   | PRI |         |       |
+-----------+---------+------+-----+---------+-------+
 
person_nn;
+----------+--------------+------+-----+---------+----------------+
| Field    | Type         | Null | Key | Default | Extra          |
+----------+--------------+------+-----+---------+----------------+
| personid | int(11)      | NO   | PRI | NULL    | auto_increment |
| name     | varchar(255) | YES  |     | NULL    |                |
| age      | int(11)      | YES  |     | NULL    |                |
+----------+--------------+------+-----+---------+----------------+
 
 
四、映射方法
 
<hibernate-mapping>
    <class name="com.lavasoft.dx._n_n.Personnn" table="PERSON_nn">
        <id name="personid">
            <generator class="identity"/>
        </id>
        <property name="name"/>
        <property name="age"/>
        <!--映射集合属性，join_1ntab是连接表表名-->
        <set name="addresses"
             table="join_nn"
                >
            <!--“column="personid"”确定PERSON_1ntab表关联到连接表的外键列名-->
            <key column="personid"/>
            <!--“column="addressid"”关联PERSON_1ntab表的Address1ntab对象的id在连接表中的列名-->
            <many-to-many
                    column="addressid"
                    class="com.lavasoft.dx._n_n.Addressnn"/>
        </set>
    </class>
</hibernate-mapping>
 
<hibernate-mapping>
    <class name="com.lavasoft.dx._n_n.Addressnn" table="ADDRESS_nn">
        <id name="addressid">
            <generator class="identity"/>
        </id>
        <property name="addressdetail"/>
    </class>
</hibernate-mapping>
 
 
五、测试方法
 
public class Test_nn {
    public static void main(String[] args){
        Addressnn add1=new Addressnn();
        Addressnn add2=new Addressnn();
        Addressnn add3=new Addressnn();
        Personnn p1=new Personnn();
        Personnn p2=new Personnn();
 
        add1.setAddressdetail("。。。。。");
        add2.setAddressdetail("。。。。。");
        add3.setAddressdetail("。。。。。");
        p1.setName("。。。。。");
        p1.setAge(30);
        p2.setName("。。。。。");
        p2.setAge(50);
 
        p1.getAddresses().add(add1);
        p1.getAddresses().add(add2);
        p2.getAddresses().add(add2);
        p2.getAddresses().add(add3);
 
        Session session= HibernateUtil.getCurrentSession();
        Transaction tx=session.beginTransaction();
        session.save(add1);
        session.save(add2);
        session.save(add3);
        session.save(p1);
        session.save(p2);
        tx.commit();
        HibernateUtil.closeSession();
    }
}
 
六、测试结果
 
1) :正常保存.
        session.save(add1);
        session.save(add2);
        session.save(add3);
        session.save(p1);
        session.save(p2);
 
Hibernate: insert into ADDRESS_nn (addressdetail) values (?)
Hibernate: insert into ADDRESS_nn (addressdetail) values (?)
Hibernate: insert into ADDRESS_nn (addressdetail) values (?)
Hibernate: insert into PERSON_nn (name, age) values (?, ?)
Hibernate: insert into PERSON_nn (name, age) values (?, ?)
Hibernate: insert into join_nn (personid, addressid) values (?, ?)
Hibernate: insert into join_nn (personid, addressid) values (?, ?)
Hibernate: insert into join_nn (personid, addressid) values (?, ?)
Hibernate: insert into join_nn (personid, addressid) values (?, ?)