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

mysql> desc 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    |                |
+----------+--------------+------+-----+---------+----------------+

mysql> desc join_nn;
+-----------+---------+------+-----+---------+-------+
| Field     | Type    | Null | Key | Default | Extra |
+-----------+---------+------+-----+---------+-------+
| personid  | int(11) | NO   | PRI |         |       |
| addressid | int(11) | NO   | PRI |         |       |
+-----------+---------+------+-----+---------+-------+

mysql> desc 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、生成的SQL脚本

/* Formatted on 2007/08/21 11:13 (QP5 v5.50) */
CREATE TABLE `address_nn` (
  `addressid` int(11) NOT NULL auto_increment,
  `addressdetail` varchar(255) default NULL,
  PRIMARY KEY  (`addressid`)
) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=gbk;

/* Formatted on 2007/08/21 11:14 (QP5 v5.50) */
CREATE TABLE `join_nn` (
  `personid` int(11) NOT NULL,
  `addressid` int(11) NOT NULL,
  PRIMARY KEY  (`personid`,`addressid`),
  KEY `FKAAB98CF5E008E752` (`personid`),
  KEY `FKAAB98CF5239F6A16` (`addressid`),
  CONSTRAINT `FKAAB98CF5239F6A16` FOREIGN KEY (`addressid`) REFERENCES `address_nn` (`addressid`),
  CONSTRAINT `FKAAB98CF5E008E752` FOREIGN KEY (`personid`) REFERENCES `person_nn` (`personid`)
) ENGINE=InnoDB DEFAULT CHARSET=gbk;

/* Formatted on 2007/08/21 11:14 (QP5 v5.50) */
CREATE TABLE `person_nn` (
  `personid` int(11) NOT NULL auto_increment,
  `name` varchar(255) default NULL,
  `age` int(11) default NULL,
  PRIMARY KEY  (`personid`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=gbk;

五、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>


六、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("郑州市经三路");
        add2.setAddressdetail("合肥市宿州路");
        add3.setAddressdetail("北京市长安路");
        p1.setName("wang");
        p1.setAge(30);
        p2.setName("lee");
        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();
    }
}

七、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 (?, ?)




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