Hibernate 一对一连接表单向关联
? 这种情况很少见，但Hibernate同样允许采用连接表关联1-1.有连接表的1-1同样只需要将N-1的many-to-one元素增加unique="true"属性即可。?一、模型介绍?一个人（Person）对应一个地址（Address）。?二、实体（省略getter、setter方法）?public class Person11tab {??? private int personid;??? private String name;??? private int age;??? private Address11tab address11tab;?public class Address11tab {??? private int addressid;??? private String addressdetail;?三、表模型?mysql> desc address_11tab;+---------------+--------------+------+-----+---------+----------------+| Field???????? | Type???????? | Null | Key | Default | Extra????????? |+---------------+--------------+------+-----+---------+----------------+| addressid???? | int(11)????? | NO?? | PRI | NULL??? | auto_increment || addressdetail | varchar(255) | YES? |???? | NULL??? |??????????????? |+---------------+--------------+------+-----+---------+----------------+?mysql> desc join_11tab;+--------------+---------+------+-----+---------+-------+| Field??????? | Type??? | Null | Key | Default | Extra |+--------------+---------+------+-----+---------+-------+| personid???? | int(11) | NO?? | PRI |???????? |?????? || address11tab | int(11) | YES? | UNI | NULL??? |?????? |+--------------+---------+------+-----+---------+-------+?mysql> desc person_11tab;+----------+--------------+------+-----+---------+----------------+| 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 2007/08/20 16:52 (QP5 v5.50) */CREATE TABLE `join_11tab` (? `personid` int(11) NOT NULL,? `address11tab` int(11) default NULL,? PRIMARY KEY? (`personid`),? UNIQUE KEY `address11tab` (`address11tab`),? KEY `FK6B44BE20C4CC3D33` (`address11tab`),? KEY `FK6B44BE209049BB1F` (`personid`),? CONSTRAINT `FK6B44BE209049BB1F` FOREIGN KEY (`personid`) REFERENCES `person_11tab` (`personid`),? CONSTRAINT `FK6B44BE20C4CC3D33` FOREIGN KEY (`address11tab`) REFERENCES `address_11tab` (`addressid`)) ENGINE=InnoDB DEFAULT CHARSET=gbk;?/* Formatted on 2007/08/20 16:53 (QP5 v5.50) */CREATE TABLE `address_11tab` (? `addressid` int(11) NOT NULL auto_increment,? `addressdetail` varchar(255) default NULL,? PRIMARY KEY? (`addressid`)) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=gbk;?/* Formatted on 2007/08/20 16:53 (QP5 v5.50) */CREATE TABLE `person_11tab` (? `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：在Person中添加Address属性，映射配置为：????? ??<!--使用join元素显式确定链接表-->??????? <join table="join_11tab">??????????? <key column="personid"/>??????????? <!--映射1-1关联属性，其中unique=“true”属性确定为“1-1”-->??????????? <many-to-one name="address11tab" unique="true"/>??????? </join>?<hibernate-mapping>??? <class name="com.lavasoft.dx._1_1_tab.Person11tab" table="PERSON_11tab">??????? <id name="personid">??????????? <generator style="padding-bottom: 0cm; padding-left: 5.4pt; width: 728pt; padding-right: 5.4pt; height: 14.25pt; padding-top: 0cm;">??????? </id>??????? <property name="name"/>??????? <property name="age"/>??????? <!--使用join元素显式确定链接表-->??????? <join table="join_11tab">??????????? <key column="personid"/>??????????? <!--映射1-1关联属性，其中unique=“true”属性确定为“1-1”-->??????????? <many-to-one name="address11tab" unique="true"/>??????? </join>??? </class></hibernate-mapping>?<hibernate-mapping>??? <class name="com.lavasoft.dx._1_1_tab.Address11tab" table="ADDRESS_11tab">??????? <id name="addressid">??????????? <generator style="padding-bottom: 0cm; padding-left: 5.4pt; width: 728pt; padding-right: 5.4pt; height: 14.25pt; padding-top: 0cm;">??????? </id>?? ?????<property name="addressdetail"/>??? </class></hibernate-mapping>??六、测试方法?public class Test_11tab {??? public static void main(String[] args){??????? Person11tab p1=new Person11tab();???????? p1.setAge(21);????? ??p1.setName("p1");???????? Address11tab add1=new Address11tab();??????? add1.setAddressdetail("郑州市经三路");???????? p1.setAddress11tab(add1);???????? Session session= HibernateUtil.getCurrentSession();??????? Transaction tx=session.beginTransaction();??????? session.save(add1);??????? session.save(p1);??????? tx.commit();??????? HibernateUtil.closeSession();??? }}?七、测试结果?1) :正常保存. 推荐这么干!??????? session.save(add1);??????? session.save(p1);?Hibernate: insert into ADDRESS_11tab (addressdetail) values (?)Hibernate: insert into PERSON_11tab (name, age) values (?Hibernate: insert into join_11tab (address11tab, personid) values (??2) :正常保存.??????? session.save(p1);??????? session.save(add1);?Hibernate: insert into PERSON_11tab (name, age) values (?Hibernate: insert into join_11tab (address11tab, personid) values (?Hibernate: insert into ADDRESS_11tab (addressdetail) values (?)Hibernate: update join_11tab set address11tab=? ?3) :正常保存.//??????? session.save(p1);??????? session.save(add1);?Hibernate: insert into ADDRESS_11tab (addressdetail) values (?)?4) : 发生异常,不能保存.??????? session.save(p1);//??????? session.save(add1);?Hibernate: insert into PERSON_11tab (name, age) values (?Hibernate: insert into join_11tab (address11tab, personid) values (?Exception in thread "main" org.hibernate.TransientObjectException: com.lavasoft.dx._1_1_tab.Address11t
