4.每颗类继承树一张表:测试

package com.bjpowernode.hibernate;

import java.util.Iterator;
import java.util.List;

import org.hibernate.Session;

import junit.framework.TestCase;

public class ExtendsTest extends TestCase {

	public void testSave1() {
		Session session = null;
		try {
			session = HibernateUtils.getSession();
			session.beginTransaction();
			
			Pig pig = new Pig();
			pig.setName("小猪猪");
			pig.setSex(true);
			pig.setWeight(200);
			session.save(pig);
			
			Bird bird = new Bird();
			bird.setName("小鸟鸟");
			bird.setSex(false);
			bird.setHeight(100);
			session.save(bird);
			
			session.getTransaction().commit();
		}catch(Exception e) {
			e.printStackTrace();
			session.getTransaction().rollback();
		}finally {
			HibernateUtils.closeSession(session);
		}
	}	
	
	/**
	 * 采用load查询，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查询，通过Animal查询
	 */
	public void testLoad2() {
		Session session = null;
		try {
			session = HibernateUtils.getSession();
			session.beginTransaction();
			Animal a = (Animal)session.load(Animal.class, 1);
			System.out.println(a.getName());
			session.getTransaction().commit();
		}catch(Exception e) {
			e.printStackTrace();
			session.getTransaction().rollback();
		}finally {
			HibernateUtils.closeSession(session);
		}
	}	
	
	/**
	 * 采用load查询，通过Animal查询
	 */
	public void testLoad3() {
		Session session = null;
		try {
			session = HibernateUtils.getSession();
			session.beginTransaction();
			Animal a = (Animal)session.load(Animal.class, 1);
			//因为load默认支持lazy，所以我们看到的是Animal的代理
			//所以采用instanceof无法鉴别出真正的类型Pig
			//所load在此情况下是不支持多态查询的
			//多态查询：hibernate在加载数据的时候，能够采用instancof鉴别出其真正的类型
			if (a instanceof Pig) {
				System.out.println(a.getName());
			}else {
				System.out.println("不是猪！");
			}
			session.getTransaction().commit();
		}catch(Exception e) {
			e.printStackTrace();
			session.getTransaction().rollback();
		}finally {
			HibernateUtils.closeSession(session);
		}
	}		
	
	/**
	 * 采用load查询，通过Animal查询
	 * 将<class>标签中的lazy设置为false
	 */
	public void testLoad4() {
		Session session = null;
		try {
			session = HibernateUtils.getSession();
			session.beginTransaction();
			Animal a = (Animal)session.load(Animal.class, 1);
			//可以正确判断出其真正的类型
			//因为映射文件中lazy设置为false，返回的不再是代理类而是真正的类型
			//所以可以鉴别出来
			//此种情况下load是支持多态查询的
			if (a instanceof Pig) {
				System.out.println(a.getName());
			}else {
				System.out.println("不是猪！");
			}
			session.getTransaction().commit();
		}catch(Exception e) {
			e.printStackTrace();
			session.getTransaction().rollback();
		}finally {
			HibernateUtils.closeSession(session);
		}
	}		
	
	/**
	 * 采用get查询，通过Animal查询
	 */
	public void testLoad5() {
		Session session = null;
		try {
			session = HibernateUtils.getSession();
			session.beginTransaction();
			Animal a = (Animal)session.get(Animal.class, 1);
			//可以鉴别出其真正的类型，因为get返回的就是具体类
			//get是支持多态查询的
			if (a instanceof Pig) {
				System.out.println(a.getName());
			}else {
				System.out.println("不是猪！");
			}
			session.getTransaction().commit();
		}catch(Exception e) {
			e.printStackTrace();
			session.getTransaction().rollback();
		}finally {
			HibernateUtils.closeSession(session);
		}
	}	
	
	/**
	 * 采用hql查询Animal
	 */
	@SuppressWarnings("unchecked")
	public void testLoad6() {
		Session session = null;
		try {
			session = HibernateUtils.getSession();
			session.beginTransaction();
			List animalList = session.createQuery("from Animal").list();
			for (Iterator iter=animalList.iterator(); iter.hasNext();) {
				Animal a = (Animal)iter.next();
				//采用hql查询返回的是真正的类型，所以hql支持多态查询
				if (a instanceof Pig) {
					System.out.println(a.getName());
				}else if (a instanceof Bird) {
					System.out.println(a.getName());
				}
			}
			session.getTransaction().commit();
		}catch(Exception e) {
			e.printStackTrace();
			session.getTransaction().rollback();
		}finally {
			HibernateUtils.closeSession(session);
		}
	}	
	
	/**
	 * 采用hql查询Animal
	 */
	@SuppressWarnings("unchecked")
	public void testLoad7() {
		Session session = null;
		try {
			session = HibernateUtils.getSession();
			session.beginTransaction();
			List list = session.createQuery("from java.lang.Object").list();
			for (Iterator iter=list.iterator(); iter.hasNext();) {
				Object o = iter.next();
				if (o instanceof Pig) {
					System.out.println(o);
				}else if (o instanceof Bird) {
					System.out.println(o);
				}
			}
			session.getTransaction().commit();
		}catch(Exception e) {
			e.printStackTrace();
			session.getTransaction().rollback();
		}finally {
			HibernateUtils.closeSession(session);
		}
	}		
}