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Hibernate
多对多双向关联
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一、模型介绍
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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。
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二、实体（省略getter、setter方法）
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public class Personnn_sx {
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private int personid;
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private String name;
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private int age;
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private Set addresses=new HashSet();
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public class Addressnn_sx {
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private int addressid;
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private String addressdetail;
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private Set persons = new HashSet();
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三、表模型
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mysql> desc person_nn_sx;
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+----------+--------------+------+-----+---------+----------------+
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| Field | Type | Null | Key | Default | Extra |
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+----------+--------------+------+-----+---------+----------------+
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| personid | int(11) | NO | PRI | NULL | auto_increment |
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| name | varchar(255) | YES | | NULL | |
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| age | int(11) | YES | | NULL | |
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+----------+--------------+------+-----+---------+----------------+
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mysql> desc address_nn_sx;
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+---------------+--------------+------+-----+---------+----------------+
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| Field | Type | Null | Key | Default | Extra |
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+---------------+--------------+------+-----+---------+----------------+
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| addressid | int(11) | NO | PRI | NULL | auto_increment |
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| addressdetail | varchar(255) | YES | | NULL | |
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+---------------+--------------+------+-----+---------+----------------+
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mysql> desc join_nn_sx;
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+-----------+---------+------+-----+---------+-------+
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| Field | Type | Null | Key | Default | Extra |
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+-----------+---------+------+-----+---------+-------+
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| addressid | int(11) | NO | PRI | | |
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| personid | int(11) | NO | PRI | | |
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+-----------+---------+------+-----+---------+-------+
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四、生成的SQL脚本
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/* Formatted on 2007/08/22 17:59 (QP5 v5.50) */
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CREATE TABLE `address_nn_sx` (
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`addressid` int(11) NOT NULL auto_increment,
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`addressdetail` varchar(255) default NULL,
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PRIMARY KEY (`addressid`)
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) ENGINE=InnoDB DEFAULT CHARSET=gbk;
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/* Formatted on 2007/08/22 17:59 (QP5 v5.50) */
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CREATE TABLE `person_nn_sx` (
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`personid` int(11) NOT NULL auto_increment,
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`name` varchar(255) default NULL,
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`age` int(11) default NULL,
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PRIMARY KEY (`personid`)
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) ENGINE=InnoDB DEFAULT CHARSET=gbk;
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/* Formatted on 2007/08/22 17:59 (QP5 v5.50) */
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CREATE TABLE `join_nn_sx` (
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`addressid` int(11) NOT NULL,
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`personid` int(11) NOT NULL,
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PRIMARY KEY (`personid`,`addressid`),
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KEY `FK6EBBC5EF6C600921` (`personid`),
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KEY `FK6EBBC5EF2A92FF3D` (`addressid`),
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CONSTRAINT `FK6EBBC5EF2A92FF3D` FOREIGN KEY (`addressid`) REFERENCES `address_nn_sx` (`addressid`),
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CONSTRAINT `FK6EBBC5EF6C600921` FOREIGN KEY (`personid`) REFERENCES `person_nn_sx` (`personid`)
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) ENGINE=InnoDB DEFAULT CHARSET=gbk;
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五、映射方法
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<hibernate-mapping>
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<class name="com.lavasoft.sx._n_n.Personnn_sx" table="PERSON_nn_sx">
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<id name="personid">
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<generator class="identity"/>
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</id>
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<property name="name"/>
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<property name="age"/>
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<!--
映射集合属性，关联到持久化类-->
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<!--table="join_1ntab_sx"
指定了连接表的名字-->
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<set name="addresses"
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table="join_nn_sx"
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cascade="all">
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<!--column="personid"
指定连接表中关联当前实体类的列名-->
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<key column="personid" not-null="true"/>
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<!--column="addressid"
是连接表中关联本实体的外键-->
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<many-to-many column="addressid"
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class="com.lavasoft.sx._n_n.Addressnn_sx"/>
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</set>
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</class>
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</hibernate-mapping>
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<hibernate-mapping>
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<class name="com.lavasoft.sx._n_n.Addressnn_sx"
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table="ADDRESS_nn_sx">
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<id name="addressid">
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<generator class="identity"/>
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</id>
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<property name="addressdetail"/>
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<!--table="join_nn_sx"
是双向多对多的连接表-->
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<set name="persons"
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inverse="true"
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table="join_nn_sx">
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<!--column="addressid"
是连接表中关联本实体的外键-->
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<key column="addressid"/>
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<many-to-many column="personid"
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class="com.lavasoft.sx._n_n.Personnn_sx"/>
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</set>
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</class>
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</hibernate-mapping>
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六、测试方法
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public class Test_nn_sx {
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public static void main(String[] args){
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Addressnn_sx add1=new Addressnn_sx();
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Addressnn_sx add2=new Addressnn_sx();
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Personnn_sx p1=new Personnn_sx();
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Personnn_sx p2=new Personnn_sx();
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add1.setAddressdetail("
郑州市经三路");
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add2.setAddressdetail("
合肥市宿州路");
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p1.setName("wang");
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p1.setAge(30);
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p2.setName("zhang");
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p2.setAge(22);
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p1.getAddresses().add(add1);
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p1.getAddresses().add(add2);
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p2.getAddresses().add(add2);
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add1.getPersons().add(p1);
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add2.getPersons().add(p1);
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add2.getPersons().add(p2);
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Session session= HibernateUtil.getCurrentSession();
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Transaction tx=session.beginTransaction();
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session.save(p1);
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session.save(p2);
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// session.saveOrUpdate(add1);
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// session.saveOrUpdate(add2);
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tx.commit();
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HibernateUtil.closeSession();
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}
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}
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七、测试结果
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1) :
正常保存.
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session.save(p1);
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session.save(p2);
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// session.saveOrUpdate(add1);
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// session.saveOrUpdate(add2);
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Hibernate: insert into PERSON_nn_sx (name, age) values (?, ?)
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Hibernate: insert into ADDRESS_nn_sx (addressdetail) values (?)
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Hibernate: insert into ADDRESS_nn_sx (addressdetail) values (?)
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Hibernate: insert into PERSON_nn_sx (name, age) values (?, ?)
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Hibernate: insert into join_nn_sx (personid, addressid) values (?, ?)
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Hibernate: insert into join_nn_sx (personid, addressid) values (?, ?)
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Hibernate: insert into join_nn_sx (personid, addressid) values (?, ?)
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本文转自 leizhimin 51CTO博客，原文链接：http://blog.51cto.com/lavasoft/39344，如需转载请自行联系原作者
