Hibernate 一对多连接表单向关联
一、模型介绍?一个人（Person）对应多个地址（Address），比如家庭地址、公司地址。?二、实体（省略getter、setter方法）?public class Person1ntab {??? private int personid;??? private String name;??? private int age;??? private Set addresses=new HashSet();?public class Address1nfk implements Serializable {??? private int addressid;??? private String addressdetail;?三、表模型?mysql> desc join_1ntab;+-----------+---------+------+-----+---------+-------+| Field???? | Type??? | Null | Key | Default | Extra |+-----------+---------+------+-----+---------+-------+| personid? | int(11) | NO?? | PRI |???????? |?????? || addressid | int(11) | NO?? | PRI |???????? |?????? |+-----------+---------+------+-----+---------+-------+?mysql> desc person_1ntab;+----------+--------------+------+-----+---------+----------------+| 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_1ntab;+---------------+--------------+------+-----+---------+----------------+| Field???????? | Type???????? | Null | Key | Default | Extra????????? |+---------------+--------------+------+-----+---------+----------------+| addressid???? | int(11)????? | NO?? | PRI | NULL??? | auto_increment || addressdetail | varchar(255) | YES? |???? | NULL??? |??????????????? |+---------------+--------------+------+-----+---------+----------------+?四、生成的SQL脚本?/* Formatted on 2007/08/21 10:58 (QP5 v5.50) */CREATE TABLE `address_1ntab` (? `addressid` int(11) NOT NULL auto_increment,? `addressdetail` varchar(255) default NULL,? PRIMARY KEY? (`addressid`)) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=gbk;?/* Formatted on 2007/08/21 10:58 (QP5 v5.50) */CREATE TABLE `join_1ntab` (? `personid` int(11) NOT NULL,? `addressid` int(11) NOT NULL,? PRIMARY KEY? (`personid`,`addressid`),? UNIQUE KEY `addressid` (`addressid`),? KEY `FK6B6078C3C8DF5BFF` (`personid`),? KEY `FK6B6078C3C2B11347` (`addressid`),? CONSTRAINT `FK6B6078C3C2B11347` FOREIGN KEY (`addressid`) REFERENCES `address_1ntab` (`addressid`),? CONSTRAINT `FK6B6078C3C8DF5BFF` FOREIGN KEY (`personid`) REFERENCES `person_1ntab` (`personid`)) ENGINE=InnoDB DEFAULT CHARSET=gbk;?/* Formatted on 2007/08/21 10:58 (QP5 v5.50) */CREATE TABLE `person_1ntab` (? `personid` int(11) NOT NULL auto_increment,? `name` varchar(255) default NULL,? `age` int(11) default NULL,? PRIMARY KEY? (`personid`)) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=gbk;??五、映射方法?<hibernate-mapping>??? <class name="com.lavasoft.dx._1_n_tab.Person1ntab" table="PERSON_1ntab">??????? <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_1ntab"??????????????? >??????????? <!--“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--> ??????????? <!--“unique="true"表示1-N，Person1ntab是1，Address1ntab是多”--> ??????????? <many-to-many??????????????????? column="addressid"??????????????????? unique="true"???????????????? ???width="971">??????? </set>??? </class></hibernate-mapping>?<hibernate-mapping>??? <class name="com.lavasoft.dx._1_n_tab.Address1ntab" table="ADDRESS_1ntab">??????? <id name="addressid">?? ?????????<generator width="971">??????? </id>??????? <property name="addressdetail"/>??? </class></hibernate-mapping>??六、测试方法?public class Test_1ntab {??? public static void main(String[] args){??????? Address1ntab add1=new Address1ntab();??????? Address1ntab add2=new Address1ntab();??????? Address1ntab add3=new Address1ntab();??????? Person1ntab p1=new Person1ntab();??????? Person1ntab p2=new Person1ntab();???????? 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 PERSON_1nfk (name, age) values (?Hibernate: insert into ADDRESS_1nfk (addressdetail) values (?)Hibernate: insert into ADDRESS_1nfk (addressdetail) values (?)Hibernate: update ADDRESS_1nfk set personid=? Hibernate: update ADDRESS_1nfk set personid=? where addressid=?