spring cache redis

一、使用开源包（spring-data-redis）

1、引入jar包

<dependency>
     <groupId>org.springframework.data</groupId>
     <artifactId>spring-data-redis</artifactId>
     <version>1.8.11.RELEASE</version>
 </dependency>

2、配置Spring xml文件

<!--  结合现在配置 -->

<bean name="redisTemplate"
class=" RedisTemplate">
       <property name="redisPool"
ref="redisPool"/>
        <property name="keySerializer"
ref="org.springframework.data.redis.serializer.StringRedisSerializer"></property>
       <property name="hashKeySerializer" ref="org.springframework.data.redis.serializer.StringRedisSerializer"></property>
</bean>

<bean name="cacheManager" class="com.config.ExtendedRedisCacheManager">
    <constructor-arg name="redisOperations" ref="redisTemplate"/>
    <constructor-arg name="cacheNames">
        <set>
            <value>default</value>
            <value>test1</value>
        </set>
    </constructor-arg>
    <!-- 默认缓存名字 -->
 <property name="defaultCacheName" value="default"/>
    <!-- 是否在容器启动时初始化 -->
 <property name="loadRemoteCachesOnStartup" value="true"/>
    <!-- 是否使用前缀 -->
 <property name="usePrefix" value="true"/>
    <!-- 前缀命名，仅当usePrefix为true时才生效
-->
 <property name="cachePrefix">
        <bean class="org.springframework.data.redis.cache.DefaultRedisCachePrefix">
            <constructor-arg name="delimiter" value=":"/>
        </bean>
    </property>
    <!-- 缓存名字和有效期的分隔符 -->
 <property name="separator" value="#"/>
    <!-- 默认有效期60 -->
 <property name="defaultExpiration" value="60"/>
</bean>

ps：redis配置继续用现有的

3、配置redis挂掉，直接访问数据库（redis挂掉，最好配置预警）

@Configuration
@EnableCaching
public class AppCacheConfigurer extends CachingConfigurerSupport {
    private Logger logger =
LoggerFactory.getLogger(AppCacheConfigurer.class);

public class AppCacheErrorHandler implements CacheErrorHandler {
        @Override
 public void handleCacheGetError(RuntimeException e,
Cache cache, Object o) {
            if (e instanceof JedisConnectionException || e instanceof RedisConnectionFailureException) {
                logger.warn("redis has lose connection:", e);
                return;
            }
            throw e;
        }

@Override
 public void handleCachePutError(RuntimeException e,
Cache cache, Object o, Object o1) {
            if (e instanceof JedisConnectionException || e instanceof RedisConnectionFailureException) {
                logger.warn("redis has lose connection:", e);
                return;
            }
            throw e;
        }

@Override
 public void handleCacheEvictError(RuntimeException
e, Cache cache, Object o) {
            throw e;
        }

@Override
 public void handleCacheClearError(RuntimeException
e, Cache cache) {
            throw e;
        }
    }

@Override
 public CacheErrorHandler errorHandler() {
        return new AppCacheErrorHandler();
    }
}

5、配置独立设置过期时间，重写RedisCacheManager

public class ExtendedRedisCacheManager extends RedisCacheManager {

private static final Logger logger =
Logger.getLogger(ExtendedRedisCacheManager.class);

private static final ScriptEngine scriptEngine = new
ScriptEngineManager().getEngineByName("JavaScript");

private static final Pattern pattern = Pattern.compile("[+\\-*/%]");

private String defaultCacheName;

private char separator = '#';

public ExtendedRedisCacheManager(RedisOperations
redisOperations) {
        this(redisOperations, Collections.<String>emptyList());
    }

public ExtendedRedisCacheManager(RedisOperations
redisOperations, Collection<String> cacheNames) {
        super(redisOperations, cacheNames);
    }

@Override
 public Cache getCache(String name) {
        // try to get cache by name
 RedisCache cache
= (RedisCache) super.getCache(name);
        if (cache != null) {
            return cache;
        }

// there's no cache which has given name
 // find separator in cache name
 int index =
name.lastIndexOf(getSeparator());
        if (index < 0) {
            return null;
        }

// split name by the separator
 String cacheName
= name.substring(0, index);
        if(StringUtils.isBlank(cacheName)){
            cacheName = defaultCacheName;
        }
        cache = (RedisCache) super.getCache(cacheName);
        if (cache == null) {
            return null;
        }

// get expiration from name
 Long expiration
= getExpiration(name, index);
        if (expiration == null || expiration < 0) {
            logger.warn("Default expiration time will be used
for cache '{}' because cannot parse '{}', cacheName : " + cacheName + ", name : " + name);
            return cache;
        }

return new RedisCache(cacheName, (isUsePrefix() ?
getCachePrefix().prefix(cacheName) : null), getRedisOperations(), expiration);
    }

public char getSeparator() {
        return separator;
    }

/**
 * Char that separates cache name and
expiration time, default: #.
 *
 * @param separator
 */
 public void setSeparator(char separator) {
        this.separator = separator;
    }

private Long getExpiration(final String name, final int separatorIndex) {
        Long expiration = null;
        String expirationAsString =
name.substring(separatorIndex + 1);
        try {
            // calculate expiration, support arithmetic
expressions.
 if(pattern.matcher(expirationAsString).find()){
                expiration = (long) Double.parseDouble(scriptEngine.eval(expirationAsString).toString());
            }else{
                expiration =
Long.parseLong(expirationAsString);
            }
        } catch (NumberFormatException ex) {
            logger.error(String.format("Cannnot separate expiration time
from cache: '%s'",
name), ex);
        } catch (ScriptException e) {
            logger.error(String.format("Cannnot separate expiration time
from cache: '%s'",
name), e);
        }

return expiration;
    }

@Override
 public void setUsePrefix(boolean usePrefix) {
        super.setUsePrefix(usePrefix);
    }

@Override
 public void setCachePrefix(RedisCachePrefix
cachePrefix) {
        super.setCachePrefix(cachePrefix);
    }

public void setDefaultCacheName(String
defaultCacheName) {
        this.defaultCacheName
= defaultCacheName;
    }
}

6、通过注解设置缓存

@Cacheable(value = "test1#60",key = "#p0")//Cacheable会判断key是否存在，增加redis缓存，设置为60秒，key为test1:xxx

@CachePut(cacheNames="test1#60",key
= "#p0")//CachePut不会判断key是否存在，直接覆盖，增加redis缓存，设置为60秒，key为test1:xxx，它每次都会触发真实方法的调用

@CacheEvict(value = "test1",key = "#p1")//删除缓存

其他缓存注解，参考spring cache注解相关定义

二、解决现有系统版本不兼容问题

1、线上spring版本为：3.2.9.RELEASE

解决兼容redis挂掉的spring版本为4.1以上

适用于现在系统的配置如下

2、引入jar包

<dependency>
     <groupId>org.springframework.data</groupId>
     <artifactId>spring-data-redis</artifactId>
     <version>1.3.4.RELEASE</version>
 </dependency>

PS：低版本主要为了兼容现在的spring版本和jedis版本

3、实现自己的Spring cache，主要是为了兼容现有redis配置（现有系统redis的实现是自己实现的）

public class ExtendRedisCache implements Cache {

private static final Logger LOG = LoggerFactory.getLogger(ExtendRedisCache.class);

/**
 * Redis
 */
 private RedisTemplate redisTemplate;

/**
 * 缓存名称
 */
 private
String name;

/**
 * 默认超时时间
 */
 private
int timeout;

@Override
 public String getName() {
        return this.name;
    }

@Override
 public Object getNativeCache() {
        return this.redisTemplate;
    }

@Override
 public ValueWrapper get(Object key) {

if (StringUtils.isEmpty(key)) {
            return null;
        }
        Jedis jedis = null;
        try{
            jedis = redisTemplate.getRedisPool().getResource();
            //键
 final String finalKey = getKey(key);

if(StringUtils.isEmpty(finalKey)){
                return null;
            }

byte[] value = jedis.get(finalKey.getBytes());
            if (value == null) {
                return null;
            }

Object object = SerializableUtil.unserialize(value);
            return (object != null ? new SimpleValueWrapper(object) : null);

}catch (Exception e){
            LOG.error("redis has lose connection:",e);
            return null;
        }finally {
            if (null != jedis) {
                jedis.close();
            }
        }

}

/**
 * 获取redis缓存键
 *
 * @param key
 * @return
 */
 private String getKey(Object key) {
        //键
 final String finalKey;

if (key instanceof String) {
            finalKey = this.name + ":" + (String) key;
        } else {
            finalKey = this.name + ":" + key.toString();
        }

return finalKey;
    }

@Override
 public void put(Object key, Object value) {

if (StringUtils.isEmpty(key) || StringUtils.isEmpty(value)) {
            return;
        }

Jedis jedis = null;
        try{
            //键
 final String finalKey = getKey(key);

if(!StringUtils.isEmpty(finalKey)){
                jedis = redisTemplate.getRedisPool().getResource();
                redisTemplate.set(finalKey.getBytes(),
SerializableUtil.serialize(value));
               
jedis.expire(finalKey.getBytes(),timeout);
            }
        }catch (Exception e){
            LOG.error("redis has lose connection:",e);
        }finally {
            if (null != jedis) {
                jedis.close();
            }
        }

}

/*
 * 根据Key 删除缓存
 */
 @Override
 public void evict(Object key) {
        if (null != key) {
            try{
                final String finalKey = getKey(key);

if (!StringUtils.isEmpty(finalKey)) {
                    redisTemplate.del(finalKey.getBytes());
                }
            }catch (Exception e){
                LOG.error("redis has lose connection:",e);
            }
        }
    }

/*
 * 清除系统缓存
 */
 @Override
 public void clear() {
        //线上不允许删除所有缓存
 }

public RedisTemplate getRedisTemplate() {
        return redisTemplate;
    }

public void setRedisTemplate(RedisTemplate
redisTemplate) {
        this.redisTemplate = redisTemplate;
    }

public void setName(String name) {
        this.name = name;
    }

public int getTimeout() {
        return timeout;
    }

public void setTimeout(int timeout) {
        this.timeout = timeout;
    }
}

4、添加spring xml配置

<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:cache="http://www.springframework.org/schema/cache"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
http://www.springframework.org/schema/cache
http://www.springframework.org/schema/cache/spring-cache.xsd
http://www.springframework.org/schema/context 
http://www.springframework.org/schema/context/spring-context-3.2.xsd ">

PS:添加红色标注地方

<!-- 启用Spring对基于注解的Cache的支持 -->
<cache:annotation-driven/>

<!-- 缓存管理器 -->
<bean id="cacheManager" class="org.springframework.cache.support.SimpleCacheManager">
    <property name="caches">
        <set>
            <bean class="ExtendRedisCache">

<property name="redisTemplate" ref="redisTemplate" /> //现有系统的redisTemplate

<property name="name" value="test1" /> //缓存名（结合key）
                <property name="timeout" value="60" /> //过期时间
            </bean>
        </set>
    </property>
</bean>

5、通过注解设置缓存

@Cacheable(value = "test1",key = "#p0")//Cacheable会判断key是否存在，增加redis缓存，key为test1:xxx，这里过期时间在xml里配置

@CachePut(cacheNames="test1",key
= "#p0")//CachePut不会判断key是否存在，直接覆盖，它每次都会触发真实方法的调用，增加redis缓存，key为test1:xxx，，这里过期时间在xml里配置

@CacheEvict(value = "test1",key = "#p1")//删除缓存

其他缓存注解，参考spring cache注解相关定义