Table per concrete class方式:
TItem有两个子类：TBook、TDVD。按照Table per concrete class方式，每个字类对应一张数据库表。对应于TBook和TDVD，我们有以下库表：
1.数据库库表
T_Book.sql
DROP
TABLE
T_Book;
CREATE
TABLE
T_Book (
id
INT
NOT
NULL
AUTO_INCREMENT
, name
VARCHAR
(
50
)
, manufacturer
VARCHAR
(
50
)
, pagecount
INT
,
PRIMARY
KEY
(id)
);
T_DVD.sql
DROP TABLE T_DVD;
CREATE TABLE T_DVD (
id INT NOT NULL AUTO_INCREMENT
, name VARCHAR(50)
, manufacturer VARCHAR(50)
, regioncode VARCHAR(30)
, PRIMARY KEY (id)
);
2.配置文件
配置文件和普通配置文件没有区别
TBook.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 package="cn.blogjava.start">
<class name="TBook" table="T_Book" catalog="sample">
<id name="id" column="id" type="java.lang.Integer">
<generator class="native" />
</id>
<property name="name" type="java.lang.String" column="name"/>
<property name="manufacturer" type="java.lang.String" column="manufacturer"/>
<property name="pageCount" type="java.lang.Integer" column="pagecount"/>
</class>
</hibernate-mapping>
TDVD.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 package="cn.blogjava.start">
<class name="TDVD" table="T_DVD" catalog="sample">
<id name="id" column="id" type="java.lang.Integer">
<generator class="native" />
</id>
<property name="name" type="java.lang.String" column="name"/>
<property name="manufacturer" type="java.lang.String" column="manufacturer"/>
<property name="regionCode" type="java.lang.String" column="regioncode"/>
</class>
</hibernate-mapping>
3.测试代码
HibernateTest.java
package cn.blogjava.start;
import java.util.Iterator;
import java.util.List;
import junit.framework.Assert;
import junit.framework.TestCase;
import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
public class HibernateTest extends TestCase {
Session session = null;
/**
* JUnit中的setUp方法在TestCase初始化的时候会自动调用
* 一般用于初始化公用资源
*/
protected void setUp() {
try {
/**
* 可以采用hibernate.properties或者hibernate.cfg.xml
* 配置文件的初始化代码
*
* 采用hibernate.properties
* Configuration config = new Configuration()；
* config.addClass(TUser.class);
*/
//采用hibernate.cfg.xml配置文件，与上面的方法对比，两个差异
//1.Configuration的初始化方式
//2.xml
Configuration config = new Configuration().configure();
SessionFactory sessionFactory = config.buildSessionFactory();
session = sessionFactory.openSession();
} catch (HibernateException e) {
// TODO: handle exception
e.printStackTrace();
}
}
/**
* JUnit中的tearDown方法在TestCase执行完毕的时候会自动调用
* 一般用于释放资源
*/
protected void tearDown() {
try {
session.close();
} catch (HibernateException e) {
// TODO: handle exception
e.printStackTrace();
}
}
/**
* 对象持久化测试(Insert方法)
*/
public void testInsert() {
Transaction tran = null;
try {
tran = session.beginTransaction();
TBook book1 = new TBook();
book1.setManufacturer("电子工业");
book1.setName("Java beginner");
book1.setPageCount(501);
TBook book2 = new TBook();
book2.setManufacturer("机械工业");
book2.setName("Thinking in java");
book2.setPageCount(1201);
TDVD dvd1 = new TDVD();
dvd1.setManufacturer("columnibia");
dvd1.setName("Lord king");
dvd1.setRegionCode("5 area");
TDVD dvd2 = new TDVD();
dvd2.setManufacturer("sony");
dvd2.setName("Forrest gump");
dvd2.setRegionCode("3 area");
session.save(book1);
session.save(book2);
session.save(dvd1);
session.save(dvd2);
session.flush();
tran.commit();
Assert.assertEquals(book1.getId().intValue()>0, true);
Assert.assertEquals(book2.getId().intValue()>0, true);
Assert.assertEquals(dvd1.getId().intValue()>0, true);
Assert.assertEquals(dvd2.getId().intValue()>0, true);
} catch (HibernateException e) {
// TODO: handle exception
e.printStackTrace();
Assert.fail(e.getMessage());
if(tran != null) {
try {
tran.rollback();
} catch (Exception e1) {
// TODO: handle exception
e1.printStackTrace();
}
}
}
}
/**
* 对象读取测试(Select方法)
*/
public void testSelect(){
//指定了具体父类，如果是from TItem，是会失败的。
List list = session.createQuery(" from cn.blogjava.start.TItem").list();
Iterator it = list.iterator();
while (it.hasNext()) {
TItem item = (TItem)it.next();
System.out.println(item.getName());
}
}
}