Hibernate 二级缓存使用

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//javabeanpublic class User {private int id;private String username;private String password;//setter getter}

// 使用缓存

User 使用缓存

<hibernate-mapping package="tao.hib.bean"><class name="User" table="sys_user"><cache usage="read-write"/><id name="id" type="integer"><generator class="native"></generator></id><property name="username" type="string" length="20"/><property name="password" type="string" length="20"/></class></hibernate-mapping>

// hib.cfg.xml 缓存

启动查询缓存

<property name="hibernate.cache.provider_class">org.hibernate.cache.EhCacheProvider</property><property name="hibernate.cache.use_query_cache">true</property><mapping resource="tao/hib/bean/User.hbm.xml" />

// 缓存配置文件

ehcache.xml

<?xml version="1.0" encoding="UTF-8"?><ehcache xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:noNamespaceSchemaLocation="http://ehcache.org/ehcache.xsd"><diskStore path="java.io.tmpdir" /><defaultCache maxElementsInMemory="10000" eternal="false"timeToIdleSeconds="300" timeToLiveSeconds="600" overflowToDisk="true" /><cache name="org.hibernate.cache.StandardQueryCache"maxElementsInMemory="10000" eternal="false" timeToIdleSeconds="300"timeToLiveSeconds="4200" overflowToDisk="true" /><cache name="org.hibernate.cache.UpdateTimestampsCache"maxElementsInMemory="5000" eternal="true" timeToIdleSeconds="0"timeToLiveSeconds="0" overflowToDisk="false" /><cache name="tao.hib.bean.User" maxElementsInMemory="10000"eternal="false" timeToIdleSeconds="10000" timeToLiveSeconds="10000"overflowToDisk="true" /></ehcache>

@SuppressWarnings("unchecked")public static void main(String[] args) {Session s = HibernateSessionFactory.getSession();//s.getTransaction().begin();//for(int i=0;i<20;i++){//User user = new User();//user.setUsername(Math.random()+"");//user.setPassword(Math.random()+"");//s.save(user);//}Criteria c = s.createCriteria(User.class);c.add(Restrictions.eq("username", "NyiiMzA7O5mT"));c.setCacheable(true);List l = c.list();User User = (User)l.get(0);System.out.println("-1-"+User.getUsername());HibernateSessionFactory.closeSession();//try{//Thread.sleep(5000);//} catch (InterruptedException e){//e.printStackTrace();//}s = HibernateSessionFactory.getSession();c=s.createCriteria(User.class);c.add(Restrictions.eq("username", "NyiiMzA7O5mT"));c.setCacheable(true);l=c.list();User=(User)l.get(0);System.out.println("-2-"+User.getUsername());HibernateSessionFactory.closeSession();//s.getTransaction().commit();}

// 再查询时候，虽然第一次 Session 关闭了，但是开启了二级缓存： SessionFactory 级别的。

c.setCacheable(true);

再第二次执行

l=c.list();

的时候将不会执行hql

其执行结果如下

----------

Hibernate: select this_.id as id0_0_, this_.username as username0_0_, this_.password as password0_0_ from sys_user this_ where this_.username=?
-1-NyiiMzA7O5mT
-2-NyiiMzA7O5mT

=========================================

如果不开启二次缓存

c.setCacheable(false); // 默认

执行结果则如下：

--------------------------------------------

Hibernate: select this_.id as id0_0_, this_.username as username0_0_, this_.password as password0_0_ from sys_user this_ where this_.username=?
-1-NyiiMzA7O5mT

Hibernate: select this_.id as id0_0_, this_.username as username0_0_, this_.password as password0_0_ from sys_user this_ where this_.username=?
-2-NyiiMzA7O5mT

Hibernate 二级缓存 使用

Hibernate 二级缓存使用