吴裕雄--天生自然轻量级JAVA EE企业应用开发Struts2Sping4Hibernate整合开发学习笔记：Hibernate_QueryCache

<?xml version="1.0" encoding="GBK"?>
<project name="hibernate" basedir="." default="">
    <property name="src" value="src"/>
    <property name="dest" value="classes"/>

    <path id="classpath">
        <fileset dir="../../lib">
            <include name="**/*.jar"/>
        </fileset>
        <pathelement path="${dest}"/>
    </path>

    <target name="compile" description="Compile all source code">
        <delete dir="${dest}"/>
        <mkdir dir="${dest}"/>
        <copy todir="${dest}">
            <fileset dir="${src}">
                <exclude name="**/*.java"/>
            </fileset>        
        </copy>
        <javac destdir="${dest}" debug="true" includeantruntime="yes"
            deprecation="false" optimize="false" failonerror="true">
            <src path="${src}"/>
            <classpath refid="classpath"/>
            <compilerarg value="-Xlint:deprecation"/>
        </javac>
    </target>

    <target name="run" description="Run the main class" depends="compile">
        <java classname="lee.NewsManager" fork="yes" failonerror="true">
            <classpath refid="classpath"/>
        </java>
    </target>

</project>

<?xml version="1.0" encoding="GBK"?>
<ehcache>
    <diskStore path="java.io.tmpdir"/>
    <defaultCache
        maxElementsInMemory="10000"
        eternal="false"
        overflowToDisk="true"
        timeToIdleSeconds="120"
        timeToLiveSeconds="120"
        diskPersistent="false"/>
</ehcache>

<?xml version="1.0" encoding="GBK"?>
<!-- 指定Hibernate配置文件的DTD信息 -->
<!DOCTYPE hibernate-configuration PUBLIC
    "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
    "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<!-- hibernate-configuration是配置文件的根元素 -->
<hibernate-configuration>
    <session-factory>
        <!-- 指定连接数据库所用的驱动 -->
        <property name="connection.driver_class">com.mysql.jdbc.Driver</property>
        <!-- 指定连接数据库的url，其中hibernate是本应用连接的数据库名 -->
        <property name="connection.url">jdbc:mysql://localhost:3306/hibernate</property>
        <!-- 指定连接数据库的用户名 -->
        <property name="connection.username">root</property>
        <!-- 指定连接数据库的密码 -->
        <property name="connection.password">32147</property>
        <!-- 指定数据库方言 -->
        <property name="dialect">org.hibernate.dialect.MySQL5InnoDBDialect</property>
        <!-- 根据需要自动创建数据库 -->
        <property name="hbm2ddl.auto">update</property>

        <!-- 指定连接池里最大连接数 -->
        <property name="hibernate.c3p0.max_size">20</property>
        <!-- 指定连接池里最小连接数 -->
        <property name="hibernate.c3p0.min_size">1</property>
        <!-- 指定连接池里连接的超时时长 -->
        <property name="hibernate.c3p0.timeout">5000</property>
        <!-- 指定连接池里最大缓存多少个Statement对象 -->
        <property name="hibernate.c3p0.max_statements">100</property>
        <property name="hibernate.c3p0.idle_test_period">3000</property>
        <property name="hibernate.c3p0.acquire_increment">2</property>
        <property name="hibernate.c3p0.validate">true</property>
        <property name="hibernate.show_sql">true</property>
        <property name="hibernate.format_sql">true</property>
        <!-- 开启二级缓存 -->
        <property name="hibernate.cache.use_second_level_cache">true</property>
        <!-- 设置缓存提供者 -->
        <property         name="hibernate.cache.region.factory_class">org.hibernate.cache.ehcache.EhCacheRegionFactory</property>

        <!-- 开启二级缓存的统计功能 -->
        <property name="hibernate.generate_statistics">true</property>
        <!-- 设置使用结构化方式来维护缓存项 -->
        <property name="hibernate.cache.use_structured_entries">true</property>

        <!-- 启用查询缓存 -->
        <property name="hibernate.cache.use_query_cache">true</property>
    
        <!-- 指定根据当前线程来界定上下文相关Session -->
        <property name="hibernate.current_session_context_class">thread</property>

        <!-- 罗列所有持久化类的类名 -->
        <mapping class="org.crazyit.app.domain.News"/>
    </session-factory>
</hibernate-configuration>

package lee;

import org.hibernate.*;
import org.hibernate.cfg.*;
import org.hibernate.service.*;
import org.hibernate.boot.registry.*;

import java.util.*;

import org.crazyit.app.domain.*;

/**
 * Description:
 * <br/>网站: <a href="http://www.crazyit.org">疯狂Java联盟</a>
 * <br/>Copyright (C), 2001-2016, Yeeku.H.Lee
 * <br/>This program is protected by copyright laws.
 * <br/>Program Name:
 * <br/>Date:
 * @author  Yeeku.H.Lee kongyeeku@163.com
 * @version  1.0
 */
public class NewsManager
{
    static Configuration conf = new Configuration()
        .configure();
    // 以Configuration实例创建SessionFactory实例
    static ServiceRegistry serviceRegistry = new StandardServiceRegistryBuilder()
        .applySettings(conf.getProperties()).build();
    static SessionFactory sf = conf.buildSessionFactory(serviceRegistry);
    public static void main(String[] args) throws Exception
    {
        NewsManager mgr = new NewsManager();
        mgr.cacheQuery();
        mgr.stat();
    }

    private void noCacheQuery()
    {
        Session session = sf.getCurrentSession();
        session.beginTransaction();
        List titles  = session.createQuery("select news.title from News news")
            // 其实无需设置，默认就是关闭缓存的。
            .setCacheable(false)
            .list();
        for(Object title : titles)
        {
            System.out.println(title);
        }
        System.out.println("-------------------------");
        // 第二次查询，因为没有使用查询缓存，因此会重新发出SQL语句进行查询
        titles  = session.createQuery("select news.title from News news")
            // 其实无需设置，默认就是关闭缓存的。
            .setCacheable(false)
            .list();
        for(Object title : titles)
        {
            System.out.println(title);
        }
        session.getTransaction().commit();
    }

    private void cacheQuery()
    {
        Session session = sf.getCurrentSession();
        session.beginTransaction();
        List titles  = session.createQuery("select news.title from News news")
            // 开启查询缓存
            .setCacheable(true)
            .list();
        for(Object title : titles)
        {
            System.out.println(title);
        }
        session.getTransaction().commit();
        System.out.println("-------------------------");
        Session sess2 = sf.getCurrentSession();
        sess2.beginTransaction();
        // 第二次查询，使用查询缓存，因此不会重新发出SQL语句进行查询
        titles  = sess2.createQuery("select news.title from News news")
            // 开启查询缓存
            .setCacheable(true)
            .list();
        for(Object title : titles)
        {
            System.out.println(title);
        }
        sess2.getTransaction().commit();
    }

    // 开启查询缓存，但使用iterate()方法查询，因此也不能缓存
    public static void cacheQueryIterator()
    {
        Session session = sf.getCurrentSession();
        session.beginTransaction();
        Iterator it  = session.createQuery("select news.title from News news")
            // 开启查询缓存
            .setCacheable(true)
            .iterate();
        while(it.hasNext())
        {
            System.out.println(it.next());
        }
        session.getTransaction().commit();
        System.out.println("-------------------------");
        Session sess2 = sf.getCurrentSession();
        sess2.beginTransaction();
        // 第二次查询，虽然使用了查询缓存，但由于使用iterate()获取查询结果，
        // 因此无法利用查询缓存。
        it  = sess2.createQuery("select news.title from News news")
            // 开启查询缓存
            .setCacheable(true)
            .iterate();
        while(it.hasNext())
        {
            System.out.println(it.next());
        }
        sess2.getTransaction().commit();
    }
    private void stat()
    {
        //----------统计查询缓存----------
        long hitCount = sf.getStatistics()
            //查询缓存的名字与HQL语句或SQL语句相同
            .getQueryStatistics("select news.title from News news")
            .getCacheHitCount();
        System.out.println("查询缓存命中的次数：" + hitCount);
    }
}

package org.crazyit.app.domain;

import javax.persistence.*;
import org.hibernate.annotations.Cache;
import org.hibernate.annotations.CacheConcurrencyStrategy;
/**
 * Description:
 * <br/>网站: <a href="http://www.crazyit.org">疯狂Java联盟</a>
 * <br/>Copyright (C), 2001-2016, Yeeku.H.Lee
 * <br/>This program is protected by copyright laws.
 * <br/>Program Name:
 * <br/>Date:
 * @author Yeeku.H.Lee kongyeeku@163.com
 * @version 1.0
 */
@Entity
@Table(name="news_inf")
@Cache(usage=CacheConcurrencyStrategy.READ_ONLY)
public class News
{
    // 消息类的标识属性
    @Id @Column(name="news_id")
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    private Integer id;
    private String title;
    private String content;

    // 无参数的构造器
    public News()
    {
    }
    // 初始化全部成员变量的构造器
    public News(Integer id , String title , String content)
    {
        this.id = id;
        this.title = title;
        this.content = content;
    }

    // id的setter和getter方法
    public void setId(Integer id)
    {
        this.id = id;
    }
    public Integer getId()
    {
        return this.id;
    }

    // title的setter和getter方法
    public void setTitle(String title)
    {
        this.title = title;
    }
    public String getTitle()
    {
        return this.title;
    }

    // content的setter和getter方法
    public void setContent(String content)
    {
        this.content = content;
    }
    public String getContent()
    {
        return this.content;
    }
}