Hibernate 多对一外键单向关联

最新推荐文章于 2025-07-28 23:27:29 发布

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本文介绍了Hibernate中实现多对一单向关联的方法，包括实体类定义、表结构设计、映射配置及测试过程。

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原文地址： http://lavasoft.blog.51cto.com/62575/39321

Hibernate 多对一外键单向关联

一、模型介绍

多个人（Person）对应一个地址（Address）。

二、实体（省略getter、setter方法）

public class Personn1fk { private int personid; private String name; private int age; private Addressn1fk addressn1fk; public class Addressn1fk { private int addressid; private String addressdetail;

三、表模型

mysql> desc address_n1kf;

+---------------+--------------+------+-----+---------+----------------+

+---------------+--------------+------+-----+---------+----------------+

| addressid | int(11) | NO | PRI | NULL | auto_increment |

+---------------+--------------+------+-----+---------+----------------+

mysql> desc person_n1kf;

+-----------+--------------+------+-----+---------+----------------+

+-----------+--------------+------+-----+---------+----------------+

| personid | int(11) | NO | PRI | NULL | auto_increment |

| age | int(11) | YES | | NULL | |

| addressId | int(11) | YES | MUL | NULL | |

+-----------+--------------+------+-----+---------+----------------+

四、生成的SQL脚本

CREATE TABLE `address_n1kf` (

`addressid` int(11) NOT NULL auto_increment,

`addressdetail` varchar(255) default NULL,

PRIMARY KEY (`addressid`)

) ENGINE=InnoDB DEFAULT CHARSET=gbk;

DROP TABLE IF EXISTS `person_n1kf`;

CREATE TABLE `person_n1kf` (

`personid` int(11) NOT NULL auto_increment,

`name` varchar(255) default NULL,

`age` int(11) default NULL,

`addressId` int(11) default NULL,

PRIMARY KEY (`personid`),

KEY `FK4571AF54A2A3EE48` (`addressId`),

CONSTRAINT `FK4571AF54A2A3EE48` FOREIGN KEY (`addressId`) REFERENCES `address_n1kf` (`addressid`)

) ENGINE=InnoDB DEFAULT CHARSET=gbk;

五、映射方法

<hibernate-mapping> <class name="com.lavasoft.dx._n_1_fk.Personn1fk" table="PERSON_n1fk"> <id name="personid"> <generator class="identity"/> </id> <property name="name"/> <property name="age"/>  <many-to-one name="addressn1fk" column="addressId"/> </class> </hibernate-mapping> <hibernate-mapping> <class name="com.lavasoft.dx._n_1_fk.Addressn1fk" table="ADDRESS_n1fk"> <id name="addressid"> <generator class="identity"/> </id> <property name="addressdetail"/> </class> </hibernate-mapping>

六、测试方法

public class Test_n1fk { public static void main(String[] args){ Personn1fk p1=new Personn1fk(); Personn1fk p2=new Personn1fk(); p1.setAge(21); p1.setName("p1"); p2.setAge(23); p2.setName("p2"); Addressn1fk add=new Addressn1fk(); add.setAddressdetail("郑州市经三路"); p1.setAddressn1fk(add); p2.setAddressn1fk(add); Session session=HibernateUtil.getCurrentSession(); Transaction tx=session.beginTransaction(); session.save(add); session.save(p1); session.save(p2); tx.commit(); HibernateUtil.closeSession(); } }

七、测试结果

1) :正常保存. 推荐这么干! session.save(p1); session.save(p2); Hibernate: insert into ADDRESS_n1kf (addressdetail) values (?) Hibernate: insert into PERSON_n1kf (name, age, addressId) values (?, ?, ?) Hibernate: insert into PERSON_n1kf (name, age, addressId) values (?, ?, ?) 2) :正常保存. session.save(p1); session.save(p2); session.save(add); Hibernate: insert into PERSON_n1kf (name, age, addressId) values (?, ?, ?) Hibernate: insert into PERSON_n1kf (name, age, addressId) values (?, ?, ?) Hibernate: insert into ADDRESS_n1kf (addressdetail) values (?) Hibernate: update PERSON_n1kf set name=?, age=?, addressId=? where personid=? Hibernate: update PERSON_n1kf set name=?, age=?, addressId=? where personid=? 3) :正常保存. session.save(add); // session.save(p1); // session.save(p2); Hibernate: insert into ADDRESS_n1kf (addressdetail) values (?) 4) : 发生异常,不能保存. // session.save(add); session.save(p1); session.save(p2); Hibernate: insert into PERSON_n1kf (name, age, addressId) values (?, ?, ?) Hibernate: insert into PERSON_n1kf (name, age, addressId) values (?, ?, ?) Exception in thread "main" org.hibernate.TransientObjectException: com.lavasoft.dx._n_1_fk.Addressn1kf

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