mybatis 整合redis作为二级缓存

核心关键在于定义一个RedisCache实现mytis实现的Cache接口

**
 * @author tele
 * @Description RedisCache由于需要传入id, 由mybatis进行创建，所以如果需要为RedisCache注入RedisTemplateUtil，直接使用@Autowired无效
 * @create 2019-09-07
 */
public class RedisCache implements Cache {

    private static RedisTemplateUtil templateUtil;

    public static void setTemplateUtil(RedisTemplateUtil templateUtil) {
        RedisCache.templateUtil = templateUtil;
    }

    //这个id实际是传入的mapper全限定名
    private final String id;

    public RedisCache(final String id) {
        if (id == null) {
            throw new IllegalArgumentException("Cache instances require an ID");
        }
        this.id = id;
    }

    public String getId() {
        return id;
    }

    public void putObject(Object key, Object value) {
        templateUtil.set(key, value);
    }

    public Object getObject(Object key) {
        return templateUtil.get(key);
    }

    public Object removeObject(Object key) {
        return null;
    }

    public void clear() {
        templateUtil.clear();
    }

    public int getSize() {
        return templateUtil.getSize();
    }

    public ReadWriteLock getReadWriteLock() {
        return null;
    }
}

定义中间类，注入工具类

@Component
public class RedisCacheTransfer {
    @Autowired
    private RedisTemplateUtil redisTemplateUtil;

    @Autowired
    public void setRedisTemplateUtil(){
        RedisCache.setTemplateUtil(redisTemplateUtil);
    }
}

工具类

/**
 * @author tele
 * @Description
 * @create 2019-09-09
 */
@Component
public class RedisTemplateUtil {
    @Autowired
    private RedisTemplate template;


    public Object get(Object key) {
        return template.opsForValue().get(key);
    }

    public void set(Object key,Object value){
        template.opsForValue().set(key, value);
    }

    public int getSize() {
      int size = (int) template.execute((RedisCallback<Integer>) connection -> {
            return connection.dbSize().intValue();
      });
      return size;
    }

    public void clear() {
        template.execute((RedisCallback)  connection -> {
            connection.flushDb();
            return null;
        });
    }
}

在对应的mapper.xml中添加cache标签

测试的时候还是先加载ClassPathXmlContext，然后获得sqlSession，注意mybatis的增删改，flushCache=true，可如果你没有调用commit并不会清空缓存

applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:p="http://www.springframework.org/schema/p"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/cache http://www.springframework.org/schema/cache/spring-cache.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd">

    <context:component-scan base-package="cn.tele"/>

    <context:property-placeholder location="classpath:redis.properties,db.properties"/>


    <!--数据源-->
    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="jdbcUrl" value="${db.url}"/>
        <property name="driverClass" value="${db.driver}"/>
        <property name="user" value="${db.username}"/>
        <property name="password" value="${db.password}"/>
        <property name="initialPoolSize" value="${db.initialPoolSize}"/>
        <property name="maxPoolSize" value="${db.maxPoolSize}"/>
        <property name="maxIdleTime" value="${db.maxIdleTime}"/>
        <property name="idleConnectionTestPeriod" value="${db.idleConnectionTestPeriod}"/>
        <property name="testConnectionOnCheckout" value="true"/>
      </bean>


    <!--mybatis-->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="mapperLocations" value="classpath*:cn/tele/bean/**/*.xml"/>
        <property name="dataSource" ref="dataSource"/>
        <property name="configurationProperties">
            <props>
                <prop key="cacheEnabled">true</prop>
                <prop key="jdbcTypeForNull">NULL</prop>
                <prop key="lazyLoadingEnabled">true</prop>
                <prop key="aggressiveLazyLoading">false</prop>
            </props>
        </property>
    </bean>

    <!--扫描mapper-->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
        <property name="basePackage" value="cn.tele"/>
    </bean>


    <!--redis连接池属性设置-->
    <bean id="poolConfig" class="redis.clients.jedis.JedisPoolConfig">
        <property name="maxIdle" value="${redis.maxIdle}"/>
        <property name="maxTotal" value="${redis.maxTotal}"/>
    </bean>

    <bean id="jedisConnFactory"
          class="org.springframework.data.redis.connection.jedis.JedisConnectionFactory"
          p:poolConfig-ref="poolConfig"  p:port="${redis.port}" p:hostName="${redis.host}"/>

    <bean id="redisTemplate"
          class="org.springframework.data.redis.core.StringRedisTemplate"
          p:connection-factory-ref="jedisConnFactory">
        <!--序列化策略-->
        <property name="keySerializer">
            <bean class="org.springframework.data.redis.serializer.Jackson2JsonRedisSerializer">
                <constructor-arg type="java.lang.Class" value="java.lang.String"/>
            </bean>
        </property>

        <property name="valueSerializer">
            <bean class="org.springframework.data.redis.serializer.JdkSerializationRedisSerializer">

            </bean>
        </property>

        <property name="hashKeySerializer">
            <bean class="org.springframework.data.redis.serializer.JdkSerializationRedisSerializer"/>
        </property>

        <property name="hashValueSerializer">
            <bean class="org.springframework.data.redis.serializer.JdkSerializationRedisSerializer"/>
        </property>
    </bean>
</beans>