hibernate3学习笔记(二十二)｜Query缓存机制 - 编程入门网

hibernate3学习笔记(二十二)｜Query缓存机制

接前面的例子：http://blog.csdn.net/kunshan_shenbin/archive/2008/09/03/2874375.aspx

测试代码如下：

1.package com.hb3.pack_22;2.3.import java.io.IOException;4.import java.sql.SQLException;5.import java.util.List;6.
7.import org.hibernate.Query;8.import org.hibernate.Session;9.import org.hibernate.SessionFactory;10.import org.hibernate.cfg.Configuration;11.
12.import com.hb3.pack_22.model.User;13.
14.public class BusinessService {15.
16.    public static void main(String[] args) throws IOException, SQLException {17.18.        Configuration config = new Configuration().configure();19.        SessionFactory sessionFactory = config.buildSessionFactory();      20.        Session session = sessionFactory.openSession();21.
22.23.        String hql = "from com.hb3.pack_22.model.User";24.25.        Query query = session.createQuery(hql);26.        List<?> users = query.list();27.28.        for(int i = 0; i < users.size(); i++) {29.            User user = (User) users.get(i);30.            System.out.println(user.getName());31.        }32.33.        query = session.createQuery(hql);34.        users = query.list();35.36.        for(int i = 0; i < users.size(); i++) {37.            User user = (User) users.get(i);38.            System.out.println(user.getName());39.        }40.
41.
42.        session.close();43.        sessionFactory.close();44.    }45.}

hibernate3学习笔记(二十二)｜Query缓存机制(2)

执行的结果为：

Hibernate: select user0_.id as id0_, user0_.name as name0_, user0_.room_id as room3_0_ from user user0_ chenyan shenbin Hibernate: select user0_.id as id0_, user0_.name as name0_, user0_.room_id as room3_0_ from user user0_ chenyan shenbin

可见，没有启用Query的快取功能。

如果打算打开Query的快取功能，首先在hibernate.cfg.xml中设定hibernate.cache.use_query_cache属性：

1.<?xml version="1.0" encoding="utf-8"?> 2.<!DOCTYPE hibernate-configuration PUBLIC3.    "-//Hibernate/Hibernate Configuration DTD 3.0//EN"4.    "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">5.6.<hibernate-configuration> 7.
8.    <session-factory> 9.        ....10.
11.        <property name="hibernate.cache.use_query_cache">true</property> 12.        ....13.14.    </session-factory> 15.
16.</hibernate-configuration>

然后在每次简历Query时，执行setCacheable(true)：

1.package com.hb3.pack_22;2.3.import java.io.IOException;4.import java.sql.SQLException;5.import java.util.List;6.
7.import org.hibernate.Query;8.import org.hibernate.Session;9.import org.hibernate.SessionFactory;10.import org.hibernate.cfg.Configuration;11.
12.import com.hb3.pack_22.model.User;13.
14.public class BusinessService {15.
16.    public static void main(String[] args) throws IOException, SQLException {17.18.        Configuration config = new Configuration().configure();19.   

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