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 width="971">??????? </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"??????????????????? width="971">??????? </set>??? </class></hibernate-mapping>?<hibernate-mapping>??? <class name="com.lavasoft.dx._n_n.Addressnn" table="ADDRESS_nn">??????? <id name="addressid">??????????? <generator width="971">??????? </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 (?, ?)