Mybatis使用Redis做二级缓存

由于redis是非关系型数据库，数据是储存到内存中的，而从内存中读取数据要比从硬盘中读取数据的速度要快很多，并且redis可以持久性化数据，所以可以用redis做数据的缓存。

首先导入jar包：Spring-data-redis.jar

配置文件：

redis.host=192.168.81.128
redis.port=6379
redis.pass=redis
redis.maxIdle=300
redis.timeout=5000
redis.maxActive=600
redis.maxWait=1000
redis.testOnBorrow=true

配置Spring.xml:

    
    <bean id="config" class="redis.clients.jedis.JedisPoolConfig">
        <property name="maxIdle" value="${redis.maxIdle}"/>
        <property name="maxTotal" value="${redis.maxActive}"/>
        <property name="maxWaitMillis" value="${redis.maxWait}"/>
        <property name="testOnBorrow" value="${redis.testOnBorrow}"/>
    bean>

      
      <bean id="connectionFactory" class="org.springframework.data.redis.connection.jedis.JedisConnectionFactory">
        <property name="hostName" value="${redis.host}"/>
        <property name="port" value="${redis.port}"/>
        <property name="password" value="${redis.pass}"/>
        <property name="timeout" value="${redis.timeout}"/>
        <property name="poolConfig" ref="config"/>
      bean>

    

     <bean id="redisUtil" class="com.chinaedu.back.util.RedisUtil">
        <property name="jedisConnectionFactory" ref="connectionFactory"/>
     bean>

     <bean id="redisCacheTransfer" class="com.chinaedu.back.util.RedisCacheTransfer">
        <property name="connectionFactory" ref="connectionFactory"/>
     bean>

配置完之后你可以测试一下是否能够连接上redis：
测试代码：

    @RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations="classpath:spring.xml")
public class TestRedis {

    @Autowired
    private JedisConnectionFactory connectionFactory;

    @Test
    public void testSetValue(){
        RedisConnection connection = connectionFactory.getConnection();
        Jedis jedis= connectionFactory.getShardInfo().createResource();
        jedis.set("name","小明");
    }
    @Test
    public void testGetValue(){
        RedisConnection connection = connectionFactory.getConnection();
        Jedis jedis= connectionFactory.getShardInfo().createResource();
        String name = jedis.get("name");
        System.out.println(name);
    }
}

如果测试成功则进行下面的步骤:
mybatis.xml:

  

<configuration>
    
    <settings>

        
        <setting name="cacheEnabled" value="true"/>

        
        <setting name="lazyLoadingEnabled" value="false"/>

        
        <setting name="multipleResultSetsEnabled" value="true"/>

        
        <setting name="useColumnLabel" value="true"/>

        
        <setting name="useGeneratedKeys" value="false"/>

        
        <setting name="autoMappingBehavior" value="PARTIAL"/>

        
        

        
        

        
        <setting name="safeRowBoundsEnabled" value="false"/>

        
        <setting name="mapUnderscoreToCamelCase" value="true"/>

        
        <setting name="localCacheScope" value="SESSION"/>

        
        <setting name="jdbcTypeForNull" value="OTHER"/>

        
        <setting name="lazyLoadTriggerMethods" value="equals,clone,hashCode,toString"/>

        
        <setting name="aggressiveLazyLoading" value="true"/>

    settings>

configuration>

mapper.xml:

<mapper namespace="com.chinaedu.back.dao.UserDao">

//自定义的cache
<cache  type="com.chinaedu.back.cache.RedisCache" />

    

    <sql id="usersql">
        select f_user_id userId, f_real_name realName,f_role_id
        roleId,f_name name,f_pwd pwd,f_eamil email,f_phone phone,f_state state
        from t_user
    sql>

    <select id="queryByCase" resultType="User">
        <include refid="usersql">include>
        <where>
            <if test="userId != null">
                f_user_id = #{userId}
            if>
            <if test="name != null">
                and f_name = #{name}
            if>
        where>
    select>
mapper>   

实现cache接口:

package com.chinaedu.back.cache;

import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;

import org.apache.ibatis.cache.Cache;
import org.springframework.data.redis.connection.RedisConnection;
import org.springframework.data.redis.connection.jedis.JedisConnection;
import org.springframework.data.redis.connection.jedis.JedisConnectionFactory;
import org.springframework.data.redis.serializer.JdkSerializationRedisSerializer;
import org.springframework.data.redis.serializer.RedisSerializer;

import redis.clients.jedis.exceptions.JedisConnectionException;

/**
 * 自定义cache
 * 
 * @author Administrator
 *
 */
public class RedisCache implements Cache {

    private static JedisConnectionFactory connectionFactory;

    private final String id;

    /**
     * The {@code ReadWriteLock}.
     */
    private final ReadWriteLock readWriteLock = new ReentrantReadWriteLock();

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

    @Override
    public String getId() {
        // TODO Auto-generated method stub
        return this.id;
    }

    @Override
    public void putObject(Object key, Object value) {
        // TODO Auto-generated method stub
        RedisConnection connection = null;
        try {
            connection = connectionFactory.getConnection();
            RedisSerializer