hibernate 继承映射(一)
每棵继承树映射成一张表
测试代码:
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public void testSave1() {
Session session = null ;
try {
session = HibernateUtils.getSession();
session.beginTransaction();
Pig pig = new Pig();
pig.setName( "猪" );
pig.setSex( true );
pig.setWeight( 100 );
session.save(pig);
Bird bird = new Bird();
bird.setName( "鸟" );
bird.setSex( false );
bird.setHeight( 50 );
session.save(bird);
session.getTransaction().commit();
} catch (Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
} finally {
HibernateUtils.closeSession(session);
}
}
/**
* 采用load,通过Pig查询
*/
public void testLoad1() {
Session session = null ;
try {
session = HibernateUtils.getSession();
session.beginTransaction();
Pig pig = (Pig)session.load(Pig. class , 1 );
System.out.println(pig.getName());
session.getTransaction().commit();
} catch (Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
} finally {
HibernateUtils.closeSession(session);
}
}
/**
* 采用load,通过Animal查询
*/
public void testLoad2() {
Session session = null ;
try {
session = HibernateUtils.getSession();
session.beginTransaction();
Animal animal = (Animal)session.load(Animal. class , 1 );
System.out.println(animal.getName());
session.getTransaction().commit();
} catch (Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
} finally {
HibernateUtils.closeSession(session);
}
}
/**
* 采用load,通过Animal查询
*/
public void testLoad3() {
Session session = null ;
try {
session = HibernateUtils.getSession();
session.beginTransaction();
Animal animal = (Animal)session.load(Animal. class , 1 );
//因为load默认只是lazy,因为我们看到的是Animal的代理对象
//所以通过instanceof是反应不出正真的对象类型的
//因此load在默认情况下是不支持多态查询的
if (animal instanceof Pig) {
System.out.println(animal.getName());
} else {
System.out.println( "不是猪" );
}
session.getTransaction().commit();
} catch (Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
} finally {
HibernateUtils.closeSession(session);
}
}
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本文转自 l363130002 51CTO博客,原文链接:http://blog.51cto.com/liuyj/1693485