最近闲来无事开始学习缓存技术，首当其冲的就是接触到redis，多的不说，直接借着现有ssm框架整合redis进去，spring和mybatis对于redis的支撑做得很好，几乎只是几个对象注入和简单配置就完成了，简单了测试一下，感觉用着还不错，比mybatis自带的缓存好用，关于两者的对比后续会再发一篇说明。下面是我的整合步骤：
下载redis软件
我是直接在Windows上使用的，就下载了Windows版的，实际项目肯定都是Linux内核，换成Linux版的也就可以了。
Window 下安装
下载地址：https://github.com/MSOpenTech/redis/releases
Linux 下安装
Windows版的运行相当简单，直接点击运行即可。
Windows-redis启动.png
引依赖
整合redis需要的maven依赖如下：(网上有多种说法，本文引入亲测可用)
<!-- spring-redis实现 -->
<dependency>
<groupId>org.springframework.data</groupId>
<artifactId>spring-data-redis</artifactId>
<version>1.6.2.RELEASE</version>
</dependency>
<!-- redis客户端jar -->
<dependency>
<groupId>redis.clients</groupId>
<artifactId>jedis</artifactId>
<version>2.8.0</version>
</dependency>
当然必要的spring和mybatis的依赖也是必要的。
spring整合redis
spring整合redis也就是使用IOC容器生成redis所需的依赖注入，配置如下：
<!-- redis数据源 -->
<bean id="poolConfig" 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>
<!-- Spring-redis连接池管理工厂 -->
<bean id="jedisConnectionFactory"
class="org.springframework.data.redis.connection.jedis.JedisConnectionFactory"
p:host-name="${redis.host}" p:port="${redis.port}" p:password="${redis.pass}"
p:pool-config-ref="poolConfig" />
<!-- 使用中间类解决RedisCache.jedisConnectionFactory的静态注入，从而使MyBatis实现第三方缓存 -->
<bean id="redisCacheTransfer" class="com.trace.app.framework.annotation.RedisCacheTransfer">
<property name="jedisConnectionFactory" ref="jedisConnectionFactory" />
</bean>
<!-- 连接池基本参数配置，类似数据库连接池 -->
<context:property-placeholder location="classpath*:redis.properties" />
<bean name="genericObjectPoolConfig" class="org.apache.commons.pool2.impl.GenericObjectPoolConfig" >
<property name="maxWaitMillis" value="-1" />
<property name="maxTotal" value="1000" />
<property name="minIdle" value="8" />
<property name="maxIdle" value="100" />
</bean>
redis的连接properties文件如下：
# Redis settings
redis.host=127.0.0.1
redis.port=6379
redis.pass=
redis.maxIdle=300
redis.maxActive=600
redis.maxWait=1000
redis.testOnBorrow=true
spring读取properties文件配置如下：
<bean id="propertyConfigurer" class="com.trace.app.framework.toolsmodel.ConvertPwdPropertyConfigurer">
<property name="locations">
<list>
<value>classpath:jdbc.properties</value>
<value>classpath:redis.properties</value>
</list>
</property>
<property name="fileEncoding" value="utf-8"></property>
</bean>
添加缓存接口实现类
通过重写Cache类中的方法，将mybatis中默认的缓存空间映射到redis空间中。
public class RedisCache implements Cache {
private static final Logger logger = LoggerFactory.getLogger(RedisCache.class);
private static JedisConnectionFactory jedisConnectionFactory;
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");
}
logger.debug("MybatisRedisCache:id=" + id);
this.id = id;
}
@Override
public void clear() {
JedisConnection connection = null;
try {
connection = jedisConnectionFactory.getConnection();
connection.flushDb();
connection.flushAll();
} catch (JedisConnectionException e) {
e.printStackTrace();
} finally {
if (connection != null) {
connection.close();
}
}
}
@Override
public String getId() {
return this.id;
}
@Override
public Object getObject(Object key) {
Object result = null;
JedisConnection connection = null;
try {
connection = jedisConnectionFactory.getConnection();
RedisSerializer<Object> serializer = new JdkSerializationRedisSerializer();
result = serializer.deserialize(connection.get(serializer.serialize(key)));
} catch (JedisConnectionException e) {
e.printStackTrace();
} finally {
if (connection != null) {
connection.close();
}
}
return result;
}
@Override
public ReadWriteLock getReadWriteLock() {
// TODO Auto-generated method stub
return this.readWriteLock;
}
@Override
public int getSize() {
int result = 0;
JedisConnection connection = null;
try {
connection = jedisConnectionFactory.getConnection();
result = Integer.valueOf(connection.dbSize().toString());
} catch (JedisConnectionException e) {
e.printStackTrace();
} finally {
if (connection != null) {
connection.close();
}
}
return result;
}
@Override
public void putObject(Object key, Object value) {
JedisConnection connection = null;
try {
connection = jedisConnectionFactory.getConnection();
RedisSerializer<Object> serializer = new JdkSerializationRedisSerializer();
connection.set(serializer.serialize(key), serializer.serialize(value));
} catch (JedisConnectionException e) {
e.printStackTrace();
} finally {
if (connection != null) {
connection.close();
}
}
}
@Override
public Object removeObject(Object key) {
JedisConnection connection = null;
Object result = null;
try {
connection = jedisConnectionFactory.getConnection();
RedisSerializer<Object> serializer = new JdkSerializationRedisSerializer();
result = connection.expire(serializer.serialize(key), 0);
} catch (JedisConnectionException e) {
e.printStackTrace();
} finally {
if (connection != null) {
connection.close();
}
}
return result;
}
public static void setJedisConnectionFactory(JedisConnectionFactory jedisConnectionFactory) {
RedisCache.jedisConnectionFactory = jedisConnectionFactory;
}
}
静态注入类参考如下：
/**
*
* @描述: 静态注入中间类
*/
public class RedisCacheTransfer
{
@Autowired
public void setJedisConnectionFactory(JedisConnectionFactory jedisConnectionFactory) {
RedisCache.setJedisConnectionFactory(jedisConnectionFactory);
}
}
mybatis二级缓存调用第三方redis
mybatis配置如下，
<settings>
<!-- 全局映射器启用缓存 -->
<setting name="cacheEnabled" value="true"/>
<!-- 允许JDBC支持生成的键 -->
<setting name="useGeneratedKeys" value="true"/>
<!-- 配置默认执行器 -->
<setting name="defaultExecutorType" value="REUSE"/>
<!-- 全局启用延迟加载 -->
<setting name="lazyLoadingEnabled" value="true"/>
<!-- 设置超时时间 -->
<setting name="defaultStatementTimeout" value="25000"/>
<!--<setting name="autoMapperBehavior" value="Full"/>-->
<!--打印sql日志-->
<setting name="logImpl" value="STDOUT_LOGGING"/>
</settings>
打开cache二级缓存。
在Mapper中添加二级缓存配置：
<cache eviction="LRU" type="com.trace.app.framework.annotation.RedisCache" />
对于增删改等更新数据库操作，需要加上 flushCache="true" ,示例如下：
<update id="activateCompany" parameterType="int" flushCache="true">
update sql ......
</update>
该字段会让更新语句执行后，刷新缓存，也就是清空缓存，避免查询信息显示不及时的问题。
测试
之后就可以直接用ssm的接口编程方式了，查询接口和更新接口执行后， redis控制台显示如下：
redis控制台显示.png
自此redis和ssm框架的整合就初步结束，小弟菜鸟一枚，欢迎批评指正。
