Hibernate 多对多双向关联

版权声明：原创作品，如需转载，请与作者联系。否则将追究法律责任。

原文地址：http://lavasoft.blog.51cto.com/62575/39344

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 (?, ?)

本文出自 “熔 岩” 博客，转载请与作者联系！

 

附件下载：
　　_n_n