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Hibernate
多对多单向关联
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一、模型介绍
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多个人（Person）对应多个地址（Address）。
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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 {
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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 {
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private int addressid;
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private String addressdetail;
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三、表模型
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mysql> desc person_nn;
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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 join_nn;
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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 | | |
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| addressid | int(11) | NO | PRI | | |
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+-----------+---------+------+-----+---------+-------+
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mysql> desc person_nn;
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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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四、生成的SQL脚本
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/* Formatted on 2007/08/21 11:13 (QP5 v5.50) */
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CREATE TABLE `address_nn` (
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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 AUTO_INCREMENT=4 DEFAULT CHARSET=gbk;
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/* Formatted on 2007/08/21 11:14 (QP5 v5.50) */
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CREATE TABLE `join_nn` (
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`personid` int(11) NOT NULL,
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`addressid` int(11) NOT NULL,
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PRIMARY KEY (`personid`,`addressid`),
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KEY `FKAAB98CF5E008E752` (`personid`),
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KEY `FKAAB98CF5239F6A16` (`addressid`),
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CONSTRAINT `FKAAB98CF5239F6A16` FOREIGN KEY (`addressid`) REFERENCES `address_nn` (`addressid`),
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CONSTRAINT `FKAAB98CF5E008E752` FOREIGN KEY (`personid`) REFERENCES `person_nn` (`personid`)
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) ENGINE=InnoDB DEFAULT CHARSET=gbk;
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/* Formatted on 2007/08/21 11:14 (QP5 v5.50) */
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CREATE TABLE `person_nn` (
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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 AUTO_INCREMENT=3 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.dx._n_n.Personnn" table="PERSON_nn">
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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，join_1ntab是连接表表名-->
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<set name="addresses"
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table="join_nn"
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>
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<!--
“column="personid"”确定PERSON_1ntab表关联到连接表的外键列名-->
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<key column="personid"/>
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<!--
“column="addressid"”关联PERSON_1ntab表的Address1ntab对象的id在连接表中的列名-->
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<many-to-many
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column="addressid"
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class="com.lavasoft.dx._n_n.Addressnn"/>
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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.dx._n_n.Addressnn" table="ADDRESS_nn">
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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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</class>
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</hibernate-mapping>
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六、测试方法
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public class Test_nn {
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public static void main(String[] args){
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Addressnn add1=new Addressnn();
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Addressnn add2=new Addressnn();
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Addressnn add3=new Addressnn();
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Personnn p1=new Personnn();
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Personnn p2=new Personnn();
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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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add3.setAddressdetail("
北京市长安路");
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p1.setName("wang");
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p1.setAge(30);
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p2.setName("lee");
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p2.setAge(50);
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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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p2.getAddresses().add(add3);
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Session session= HibernateUtil.getCurrentSession();
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Transaction tx=session.beginTransaction();
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session.save(add1);
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session.save(add2);
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session.save(add3);
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session.save(p1);
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session.save(p2);
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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(add1);
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session.save(add2);
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session.save(add3);
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session.save(p1);
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session.save(p2);
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Hibernate: insert into ADDRESS_nn (addressdetail) values (?)
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Hibernate: insert into ADDRESS_nn (addressdetail) values (?)
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Hibernate: insert into ADDRESS_nn (addressdetail) values (?)
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Hibernate: insert into PERSON_nn (name, age) values (?, ?)
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Hibernate: insert into PERSON_nn (name, age) values (?, ?)
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Hibernate: insert into join_nn (personid, addressid) values (?, ?)
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Hibernate: insert into join_nn (personid, addressid) values (?, ?)
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Hibernate: insert into join_nn (personid, addressid) values (?, ?)
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Hibernate: insert into join_nn (personid, addressid) values (?, ?)
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本文转自 leizhimin 51CTO博客，原文链接：http://blog.51cto.com/lavasoft/39324，如需转载请自行联系原作者
