15.开启二级缓存

一、导入依赖

1 <!-- https://mvnrepository.com/artifact/org.hibernate/hibernate-ehcache -->
2         <dependency>
3             <groupId>org.hibernate</groupId>
4             <artifactId>hibernate-ehcache</artifactId>
5             <version>5.6.7.Final</version>
6         </dependency>

二、ehcache.xml

 1 <?xml version="1.0" encoding="utf-8" ?>
 2 <ehcache>
 3 
 4     <diskStore path="d:/hibernate_cache"></diskStore>
 5     <!-- 默认缓存配置 -->
 6     <defaultCache maxElementsInMemory="10000"
 7                   maxElementsOnDisk="0"
 8                   eternal="false"
 9                   timeToIdleSeconds="120"
10                   timeToLiveSeconds="120"
11                   diskPersistent="false"
12                   diskSpoolBufferSizeMB="30"
13                   overflowToDisk="true"
14                   memoryStoreEvictionPolicy="LRU"
15     />
16 
17     <!-- user缓存配置 -->
18     <cache name = "UserTest"
19            maxElementsInMemory="10000"
20            eternal="false"
21            timeToIdleSeconds="120"
22            timeToLiveSeconds="120"
23            overflowToDisk="true"/>
24     <!--maxElementsInMemory 在内存中缓存的最大对象数量（正整数）-->
25     <!--maxElementsOnDisk 在磁盘中缓存的最大对象数量（正整数）默认为0 表示不限制 -->
26     <!--eternal 设置缓存对象是否永久保存-->
27     <!--timeToIdleSeconds 设置对象在多长时间没有被访问就会失效 单位为秒 -->
28     <!--timeToLiveSeconds 设置对象的存活时间 单位为秒 -->
29     <!--overflowToDisk 如果内存中数据超出内存限制 是否要缓存到磁盘上-->
30     <!--diskPersistent 设置是否在磁盘上持久化-->
31     <!--diskSpoolBufferSizeMB 设置使用的磁盘大小 每个cache使用各自的spool 默认值为30 -->
32     <!--memoryStoreEvictionPolicy 设置向磁盘缓存的策略 默认为LRU 可选FIFO、LFU-->
33     <!--FIFO: 先进先出 / LFU： 最少被使用 / LRU： 最近最少使用（默认）-->
34 
35 </ehcache>

使用user级别ehcache示例（一般就用默认的）

<collection-cache region="UserTest" collection="com.sdkj.hibernate.domain.HTeacherEntity.studentEntities" usage="read-write"/>

三、hibernate.cfg.xml（全粘进来注意配置所在位置）

 1 package com.sdkj.hibernate.controller;
 2 
 3 import com.sdkj.hibernate.domain.HTeacherEntity;
 4 import com.sdkj.hibernate.util.CommonUtil;
 5 import org.hibernate.Session;
 6 import org.hibernate.SessionFactory;
 7 import org.hibernate.Transaction;
 8 import org.junit.jupiter.api.Test;
 9 
10 /**
11  * @Author wangshuo
12  * @Date 2022/4/10, 16:55
13  * Please add a comment
14  */
15 public class TestCache extends CommonUtil {
16 
17     //开启类级别的二级缓存就会只查一次
18     @Test
19     public void testLei(){
20 
21         SessionFactory sessionFactory = getSessionFactory();
22         Session session = sessionFactory.openSession();
23         Transaction transaction = session.beginTransaction();
24 
25         System.out.println(session.get(HTeacherEntity.class, 6).getTname());
26 
27         transaction.commit();
28         session.close();
29 
30         session = sessionFactory.openSession();
31         transaction = session.beginTransaction();
32 
33         //一级缓存时session级别的缓存，我关闭了session再开启一级缓存就会失效
34         System.out.println(session.get(HTeacherEntity.class, 6).getTname());
35     }
36 
37     //开启类级别的二级缓存 并且 开启集合级别的二级缓存就会只查一次
38     @Test
39     public void testJiHe(){
40 
41         SessionFactory sessionFactory = getSessionFactory();
42         Session session = sessionFactory.openSession();
43         Transaction transaction = session.beginTransaction();
44 
45         HTeacherEntity load = session.load(HTeacherEntity.class, 2);
46         System.out.println(load.getStudentEntities());
47 
48         session = sessionFactory.openSession();
49         transaction = session.beginTransaction();
50 
51         HTeacherEntity load1 = session.load(HTeacherEntity.class, 2);
52         System.out.println(load1.getStudentEntities());
53     }
54 }

1.类级别的二级缓存

 1 <?xml version='1.0' encoding='utf-8'?>
 2 <!DOCTYPE hibernate-configuration PUBLIC
 3         "-//Hibernate/Hibernate Configuration DTD//EN"
 4         "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
 5 <hibernate-configuration>
 6   <session-factory>
 7     <property name="connection.url">jdbc:mysql://localhost:3306/678</property>
 8     <property name="connection.driver_class">com.mysql.cj.jdbc.Driver</property>
 9     <property name="connection.username">root</property>
10     <property name="connection.password">678678</property>
11     <!-- <property name="connection.username"/> -->
12     <!-- <property name="connection.password"/> -->
13 
14     <!-- DB schema will be updated if needed -->
15     <!-- <property name="hibernate.hbm2ddl.auto">update</property> -->
16     <!--  hibernate配置  -->
17     <property name="hibernate.dialect">org.hibernate.dialect.MySQL8Dialect</property>
18     <property name="hibernate.show_sql">true</property>
19     <property name="hibernate.format_sql">true</property>
20     <!-- 表结构变化时执行修改表命令 不删表重建 -->
21     <property name="hibernate.hbm2ddl.auto">update</property>
22     <!-- 设置每次查询从数据库中读取的条数 MySQL数据库不支持（所以企业级涉及大数据量数据的存储基本采用Oracle数据库） -->
23     <property name="hibernate.jdbc.fetch_size">100</property>
24     <!-- 设置批量删除和批量更新 -->
25     <property name="hibernate.jdbc.batch_size">30</property>
26 
27     <!-- c3p0属性配置 -->
28     <!-- 配置启用c3p0连接池 -->
29     <property name="hibernate.connection.provider_class">org.hibernate.c3p0.internal.C3P0ConnectionProvider</property>
30     <property name="hibernate.c3p0.max_size">500</property>
31     <property name="hibernate.c3p0.min_size">1</property>
32     <!-- 设置缓存里最多有多少个statement对象 -->
33     <property name="hibernate.c3p0.max_statements">100</property>
34     <!-- 超时时间 -->
35     <property name="hibernate.c3p0.timeout">5000</property>
36     <!-- 配置每隔多少秒 扫描连接池所有连接，清理超时连接 -->
37     <property name="hibernate.c3p0.idle_test_period">2000</property>
38     <!-- 配置当连接池连接数耗尽时，每次向MySQL申请多少条连接 -->
39     <property name="hibernate.c3p0.acquire_increment">100</property>
40 
41     <!--缓存配置-->
42     <property name="hibernate.cache.use_second_level_cache">true</property>
43     <property name="hibernate.cache.region.factory_class">org.hibernate.cache.ehcache.internal.EhcacheRegionFactory</property>
44 
45     <mapping resource="T2UserEntity.hbm.xml"/>
46     <mapping class="com.sdkj.hibernate.domain.T2UserEntity"/>
47     <mapping resource="HStudentEntity.hbm.xml"/>
48     <mapping class="com.sdkj.hibernate.domain.HStudentEntity"/>
49     <mapping resource="HTeacherEntity.hbm.xml"/>
50     <mapping class="com.sdkj.hibernate.domain.HTeacherEntity"/>
51     <mapping class="com.sdkj.hibernate.domain.HCardEntity"/>
52     <mapping resource="CardEntity.hbm.xml"/>
53     <mapping class="com.sdkj.hibernate.domain.HPersonEntity"/>
54     <mapping resource="PersonEntity.hbm.xml"/>
55     <!--<mapping class="com.sdkj.hibernate.domain.TeacherEntity_Many_To_Many"/>-->
56     <mapping class="com.sdkj.hibernate.domain.CourseEntity"/>
57     <mapping resource="CourseEntity.hbm.xml"/>
58     <mapping class="com.sdkj.hibernate.domain.CourseEntity_Many_To_Many"/>
59     <mapping resource="CourseEntityMTM.hbm.xml"/>
60     <mapping class="com.sdkj.hibernate.domain.SXTeacherEntity_Many_To_Many"/>
61     <mapping resource="SXTeacherEntityMTM.hbm.xml"/>
62     <mapping class="com.sdkj.hibernate.domain.Test_Student"/>
63     <mapping resource="TestStudent.hbm.xml"/>
64     <mapping class="com.sdkj.hibernate.domain.TYhOrder1Entity"/>
65     <mapping resource="TYhOrder1Entity.hbm.xml"/>
66 
67     <!-- 配置开启二级缓存的类 -->
68     <class-cache class="com.sdkj.hibernate.domain.HTeacherEntity" usage="read-write"></class-cache>
69   </session-factory>
70 </hibernate-configuration>

2.集合级别的二级缓存

1 <class-cache class="com.sdkj.hibernate.domain.HStudentEntity" usage="read-write"/>
2     <collection-cache collection="com.sdkj.hibernate.domain.HTeacherEntity.studentEntities" usage="read-write"/>

四、查询级别的二级缓存

 1 //带条件的查询
 2     //开启类级别的二级缓存 并且 开启集合级别的二级缓存 并且 开启查询级别的二级缓存 就会只查一次
 3     @Test
 4     public void testChaXun(){
 5 
 6         SessionFactory sessionFactory = getSessionFactory();
 7         Session session = sessionFactory.openSession();
 8         Transaction transaction = session.beginTransaction();
 9 
10         String hql = " select new TYhOrder1Entity(e.id,e.price,e.date) from TYhOrder1Entity e where 1 = 1 and e.id < 50";
11         Query<TYhOrder1Entity> query = session.createQuery(hql);
12 
13         //query.setCacheable(true);开启查询二级缓存（依赖于二级缓存）
14         query.setCacheable(true);
15         for (TYhOrder1Entity tYhOrder1Entity : query.list()) {
16 
17             System.out.println("id:"+tYhOrder1Entity.getId()+"  price:"+tYhOrder1Entity.getPrice()
18                     +"  date:"+tYhOrder1Entity.getDate()
19             );
20         }
21 
22         //再调用一次
23         for (TYhOrder1Entity tYhOrder1Entity : query.list()) {
24 
25             System.out.println("id:"+tYhOrder1Entity.getId()+"  price:"+tYhOrder1Entity.getPrice()
26                     +"  date:"+tYhOrder1Entity.getDate()
27             );
28         }
29     }

1 <!-- 查询缓存 -->
2     <property name="hibernate.cache.use_query_cache">true</property>

 1 @Test
 2     public void testShiJianChuo(){
 3 
 4         SessionFactory sessionFactory = getSessionFactory();
 5         Session session = sessionFactory.openSession();
 6         Transaction transaction = session.beginTransaction();
 7 
 8         String hql = " select new TYhOrder1Entity(e.id,e.price,e.date) from TYhOrder1Entity e where 1 = 1 and e.id < 10";
 9         Query<TYhOrder1Entity> query = session.createQuery(hql);
10 
11         //query.setCacheable(true);开启查询二级缓存（依赖于二级缓存）
12         query.setCacheable(true);
13         for (TYhOrder1Entity tYhOrder1Entity : query.list()) {
14 
15             System.out.println("id:"+tYhOrder1Entity.getId()+"  price:"+tYhOrder1Entity.getPrice()
16                     +"  date:"+tYhOrder1Entity.getDate()
17             );
18         }
19 
20         //两次查询中间改一下结果之一 数据的值
21         TYhOrder1Entity load = session.load(TYhOrder1Entity.class, 6);
22         load.setDate(new Date());
23 
24         //再调用一次
25         //此时hibernate发现了，小伙想搞事情？？  hibernate就会再查一次
26         for (TYhOrder1Entity tYhOrder1Entity : query.list()) {
27 
28             System.out.println("id:"+tYhOrder1Entity.getId()+"  price:"+tYhOrder1Entity.getPrice()
29                     +"  date:"+tYhOrder1Entity.getDate()
30             );
31         }
32     }

发表于 2022-04-10 21:48 荣慕平阅读(63) 评论(0) 编辑收藏举报

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15.开启二级缓存

一、导入依赖

二、ehcache.xml

使用user级别ehcache示例（一般就用默认的）

三、hibernate.cfg.xml（全粘进来 注意配置所在位置）

1.类级别的二级缓存

2.集合级别的二级缓存

四、查询级别的二级缓存

公告

三、hibernate.cfg.xml（全粘进来注意配置所在位置）