Hibernate 多对多双向关联

Hibernate 多对多双向关联

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_sx {

private int personid;

private String name;

private int age;

private Set addresses=new HashSet();

public class Addressnn_sx {

private int addressid;

private String addressdetail;

private Set persons = new HashSet();

三、表模型

mysql> desc person_nn_sx;

+----------+--------------+------+-----+---------+----------------+

| 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 address_nn_sx;

+---------------+--------------+------+-----+---------+----------------+

| Field         | Type         | Null | Key | Default | Extra          |

+---------------+--------------+------+-----+---------+----------------+

| addressid     | int(11)      | NO   | PRI | NULL    | auto_increment |

| addressdetail | varchar(255) | YES  |     | NULL    |                |

+---------------+--------------+------+-----+---------+----------------+

mysql> desc join_nn_sx;

+-----------+---------+------+-----+---------+-------+

| Field     | Type    | Null | Key | Default | Extra |

+-----------+---------+------+-----+---------+-------+

| addressid | int(11) | NO   | PRI |         |       |

| personid  | int(11) | NO   | PRI |         |       |

+-----------+---------+------+-----+---------+-------+

四、生成的SQL脚本

/* Formatted on 2007/08/22 17:59 (QP5 v5.50) */

CREATE TABLE `address_nn_sx` (

`addressid` int(11) NOT NULL auto_increment,

`addressdetail` varchar(255) default NULL,

PRIMARY KEY  (`addressid`)

) ENGINE=InnoDB DEFAULT CHARSET=gbk;

/* Formatted on 2007/08/22 17:59 (QP5 v5.50) */

CREATE TABLE `person_nn_sx` (

`personid` int(11) NOT NULL auto_increment,

`name` varchar(255) default NULL,

`age` int(11) default NULL,

PRIMARY KEY  (`personid`)

) ENGINE=InnoDB DEFAULT CHARSET=gbk;

/* Formatted on 2007/08/22 17:59 (QP5 v5.50) */

CREATE TABLE `join_nn_sx` (

`addressid` int(11) NOT NULL,

`personid` int(11) NOT NULL,

PRIMARY KEY  (`personid`,`addressid`),

KEY `FK6EBBC5EF6C600921` (`personid`),

KEY `FK6EBBC5EF2A92FF3D` (`addressid`),

CONSTRAINT `FK6EBBC5EF2A92FF3D` FOREIGN KEY (`addressid`) REFERENCES `address_nn_sx` (`addressid`),

CONSTRAINT `FK6EBBC5EF6C600921` FOREIGN KEY (`personid`) REFERENCES `person_nn_sx` (`personid`)

) ENGINE=InnoDB DEFAULT CHARSET=gbk;

五、映射方法

<hibernate-mapping>

<class name="com.lavasoft.sx._n_n.Personnn_sx" table="PERSON_nn_sx">

<id name="personid">

<generator class="identity"/>

</id>

<property name="name"/>

<property name="age"/>

<!--映射集合属性，关联到持久化类-->

<!--table="join_1ntab_sx"指定了连接表的名字-->

<set name="addresses"

table="join_nn_sx"

cascade="all">

<!--column="personid"指定连接表中关联当前实体类的列名-->

<key column="personid" not-null="true"/>

<!--column="addressid"是连接表中关联本实体的外键-->

<many-to-many column="addressid"

class="com.lavasoft.sx._n_n.Addressnn_sx"/>

</set>

</class>

</hibernate-mapping>

<hibernate-mapping>

<class name="com.lavasoft.sx._n_n.Addressnn_sx"

table="ADDRESS_nn_sx">

<id name="addressid">

<generator class="identity"/>

</id>

<property name="addressdetail"/>

<!--table="join_nn_sx"是双向多对多的连接表-->

<set name="persons"

inverse="true"

table="join_nn_sx">

<!--column="addressid"是连接表中关联本实体的外键-->

<key column="addressid"/>

<many-to-many column="personid"

class="com.lavasoft.sx._n_n.Personnn_sx"/>

</set>

</class>

</hibernate-mapping>

六、测试方法

public class Test_nn_sx {

public static void main(String[] args){

Addressnn_sx add1=new Addressnn_sx();

Addressnn_sx add2=new Addressnn_sx();

Personnn_sx p1=new Personnn_sx();

Personnn_sx p2=new Personnn_sx();

add1.setAddressdetail("郑州市经三路");

add2.setAddressdetail("合肥市宿州路");

p1.setName("wang");

p1.setAge(30);

p2.setName("zhang");

p2.setAge(22);

p1.getAddresses().add(add1);

p1.getAddresses().add(add2);

p2.getAddresses().add(add2);

add1.getPersons().add(p1);

add2.getPersons().add(p1);

add2.getPersons().add(p2);

Session session= HibernateUtil.getCurrentSession();

Transaction tx=session.beginTransaction();

session.save(p1);

session.save(p2);

//        session.saveOrUpdate(add1);

//        session.saveOrUpdate(add2);

tx.commit();

HibernateUtil.closeSession();

}

}

七、测试结果

1) :正常保存.

session.save(p1);

session.save(p2);

//        session.saveOrUpdate(add1);

//        session.saveOrUpdate(add2);

Hibernate: insert into PERSON_nn_sx (name, age) values (?, ?)

Hibernate: insert into ADDRESS_nn_sx (addressdetail) values (?)

Hibernate: insert into ADDRESS_nn_sx (addressdetail) values (?)

Hibernate: insert into PERSON_nn_sx (name, age) values (?, ?)

Hibernate: insert into join_nn_sx (personid, addressid) values (?, ?)

Hibernate: insert into join_nn_sx (personid, addressid) values (?, ?)

Hibernate: insert into join_nn_sx (personid, addressid) values (?, ?)