hibernate一对一主键关联映射（二）－－

1.新建工程项目hibernate_one2one_pk_2,加入hibernate所需的Jar包和数据库mysql驱动Jar包。

2.编写工具类HibernateUtils.java和ExportDB.java,代码如下：

HibernateUtils.java

package com.i51pro.hibernate;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
public class HibernateUtils {
private static SessionFactory sessionFactory;
static {
try {
Configuration cfg = new Configuration().configure();
sessionFactory = cfg.buildSessionFactory();
} catch (Exception e) {
e.printStackTrace();
}
}
public static SessionFactory getSessionFactory() {
return sessionFactory;
}
public static Session getSession() {
return sessionFactory.openSession();
}
public static void closeSession(Session session) {
if (session != null) {
if (session.isOpen()) {
session.close();
}
}
}
}

ExportDB.java

package com.i51pro.hibernate;
import org.hibernate.cfg.Configuration;
import org.hibernate.tool.hbm2ddl.SchemaExport;
public class ExportDB {
/**
* @param args
*/
public static void main(String[] args) {
Configuration cfg = new Configuration().configure();
SchemaExport export = new SchemaExport(cfg);
export.create(true, true);
}
}

3.编写实体类和映射文件，代码如下：

IdCard.java

package com.i51pro.hibernate;
public class IdCard {
private int id;
private String cardNo;
private Person person;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getCardNo() {
return cardNo;
}
public void setCardNo(String cardNo) {
this.cardNo = cardNo;
}
public Person getPerson() {
return person;
}
public void setPerson(Person person) {
this.person = person;
}
}

Person.java

package com.i51pro.hibernate;
public class Person {
private int id;
private String name;
private IdCard idCard;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public IdCard getIdCard() {
return idCard;
}
public void setIdCard(IdCard idCard) {
this.idCard = idCard;
}
}

IdCard.hbm.xml

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="com.i51pro.hibernate.IdCard" table="t_idcard">
<id name="id">
<generator class="native"/>
</id>
<property name="cardNo"/>
<one-to-one name="person" />
</class>
</hibernate-mapping>

Person.hbm.xml

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="com.i51pro.hibernate.Person" table="t_person">
<id name="id">
<generator class="foreign">
<param name="property">idCard</param>
</generator>
</id>
<property name="name"/>
<one-to-one name="idCard" constrained="true" />
</class>
</hibernate-mapping>

4.编写hibernate映射文件，代码如下：

hibernate.cfg.xml

<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="hibernate.connection.url">jdbc:mysql://localhost/hibernate_one2one_pk_2</property>
<property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="hibernate.connection.username">root</property>
<property name="hibernate.connection.password">admin</property>
<property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
<property name="hibernate.show_sql">true</property>
<mapping resource="com/i51pro/hibernate/Person.hbm.xml"/>
<mapping resource="com/i51pro/hibernate/IdCard.hbm.xml"/>
</session-factory>
</hibernate-configuration>

5.在工程项目hibernate_one2one_pk_2下，新建一个SourceFolder,命名为test,在test包下编写单元测试类One2OneTest.java进行单元测试,代码如下：

package com.i51pro.hibernate;
import org.hibernate.Session;
import org.hibernate.Transaction;
import junit.framework.TestCase;
public class One2OneTest extends TestCase {
public void testSave1() {
Session session = null;
try {
session = HibernateUtils.getSession();
Transaction tx = session.beginTransaction();
IdCard idCard = new IdCard();
idCard.setCardNo("88888888");
Person person = new Person();
person.setName("李小晚");
person.setIdCard(idCard);
/**
* 不会发生TransientOabjectException异常
* 因为一对一主键关联映射中，默认了cascade属性
*/
session.save(person);
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
}
public void testLoad1() {
Session session = null;
try {
session = HibernateUtils.getSession();
Transaction tx = session.beginTransaction();
Person person = (Person)session.load(Person.class, 1);
System.out.println("person.name:" + person.getName() );
System.out.println("idCard.name:" + person.getIdCard().getCardNo());
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}
}
public void testLoad2() {
Session session = null;
try {
session = HibernateUtils.getSession();
Transaction tx = session.beginTransaction();
IdCard idCard = (IdCard)session.load(IdCard.class, 1);
System.out.println("person.name:" + idCard.getPerson().getName());
System.out.println("idCard.name:" + idCard.getCardNo());
tx.commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
}
}

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