Hibernate二级缓存的使用

1.加入ehcase.xml文件；
2.在配置文件中加入如下代码：
<!-- 启用二级缓存，默认是启用的 -->
<property name="hibernate.cache.use_second_level_cache">true</property>
<!-- 指定缓存产品提供商 -->
<property name="hibernate.cache.provider_class">org.hibernate.cache.EhCacheProvider</property>

zh

package com.bjsxt.hibernate;

import org.hibernate.CacheMode;
import org.hibernate.Session;
import org.hibernate.SessionFactory;

import junit.framework.TestCase;

/**
 * 测试二级缓存
 * @author Administrator
 *
 */
public class CacheLevel2Test extends TestCase {

	/**
	 * 开启二级缓存，开启两个session，分别调用load方法 
	 */
	public void testCache1() {
		Session session = null;
		try {
			session = HibernateUtils.getSession();
			session.beginTransaction();
			
			Student student = (Student)session.load(Student.class, 1);
			System.out.println("student.name=" + student.getName());
			session.getTransaction().commit();
		}catch(Exception e) {
			e.printStackTrace();
			session.getTransaction().rollback();
		}finally {
			HibernateUtils.closeSession(session);
		}
		
		try {
			session = HibernateUtils.getSession();
			session.beginTransaction();
			
			//不会发出sql，因为开启了二级缓存，session是共享二级缓存的
			Student student = (Student)session.load(Student.class, 1);
			System.out.println("student.name=" + student.getName());
			session.getTransaction().commit();
		}catch(Exception e) {
			e.printStackTrace();
			session.getTransaction().rollback();
		}finally {
			HibernateUtils.closeSession(session);
		}
		
	}

	/**
	 * 开启二级缓存，开启两个session，分别调用get方法 
	 */
	public void testCache2() {
		Session session = null;
		try {
			session = HibernateUtils.getSession();
			session.beginTransaction();
			
			Student student = (Student)session.get(Student.class, 1);
			System.out.println("student.name=" + student.getName());
			session.getTransaction().commit();
		}catch(Exception e) {
			e.printStackTrace();
			session.getTransaction().rollback();
		}finally {
			HibernateUtils.closeSession(session);
		}
		
		try {
			session = HibernateUtils.getSession();
			session.beginTransaction();
			
			//不会发出sql，因为开启了二级缓存，session是共享二级缓存的
			Student student = (Student)session.get(Student.class, 1);
			System.out.println("student.name=" + student.getName());
			session.getTransaction().commit();
		}catch(Exception e) {
			e.printStackTrace();
			session.getTransaction().rollback();
		}finally {
			HibernateUtils.closeSession(session);
		}
	}
	
	
	/**
	 * 开启二级缓存，先调用load，再使用SessionFactory清除二级缓存 
	 */
	public void testCache3() {
		Session session = null;
		try {
			session = HibernateUtils.getSession();
			session.beginTransaction();
			
			Student student = (Student)session.load(Student.class, 1);
			System.out.println("student.name=" + student.getName());
			session.getTransaction().commit();
		}catch(Exception e) {
			e.printStackTrace();
			session.getTransaction().rollback();
		}finally {
			HibernateUtils.closeSession(session);
		}
		
		//管理二级缓存
		SessionFactory factory = HibernateUtils.getFactory();
		//factory.evict(Student.class);
		factory.evict(Student.class, 1);
		
		try {
			session = HibernateUtils.getSession();
			session.beginTransaction();
			
			//会发出sql，因为二级缓存中的数据被清除了
			Student student = (Student)session.load(Student.class, 1);
			System.out.println("student.name=" + student.getName());
			session.getTransaction().commit();
		}catch(Exception e) {
			e.printStackTrace();
			session.getTransaction().rollback();
		}finally {
			HibernateUtils.closeSession(session);
		}
		
	}
	
	/**
	 * 一级缓存和二级缓存的交互
	 */
	public void testCache4() {
		Session session = null;
		try {
			session = HibernateUtils.getSession();
			session.beginTransaction();
			
			//仅向二级缓存读数据，而不向二级缓存写数据
			session.setCacheMode(CacheMode.GET);
			
			Student student = (Student)session.load(Student.class, 1);
			System.out.println("student.name=" + student.getName());
			session.getTransaction().commit();
		}catch(Exception e) {
			e.printStackTrace();
			session.getTransaction().rollback();
		}finally {
			HibernateUtils.closeSession(session);
		}
		
		try {
			session = HibernateUtils.getSession();
			session.beginTransaction();
			
			Student student = (Student)session.load(Student.class, 1);
			System.out.println("student.name=" + student.getName());
			session.getTransaction().commit();
		}catch(Exception e) {
			e.printStackTrace();
			session.getTransaction().rollback();
		}finally {
			HibernateUtils.closeSession(session);
		}

		try {
			session = HibernateUtils.getSession();
			session.beginTransaction();
			
			//指向二级缓存放数据，而不从二级缓存读数据
			session.setCacheMode(CacheMode.PUT);
			
			//会发出sql，因为CacheMode设置为PUT，它不会读取二级缓存中的数据
			Student student = (Student)session.load(Student.class, 1);
			System.out.println("student.name=" + student.getName());
			session.getTransaction().commit();
		}catch(Exception e) {
			e.printStackTrace();
			session.getTransaction().rollback();
		}finally {
			HibernateUtils.closeSession(session);
		}
		
	}
	
}