@Bean
public CacheManager cacheManager(RedisTemplate redisTemplate) {
    RedisCacheManager cacheManager= new RedisCacheManager(redisTemplate);
    cacheManager.setDefaultExpiration(60);
    Map<String,Long> expiresMap=new HashMap<>();
    expiresMap.put("Product",5L);
    cacheManager.setExpires(expiresMap);
    return cacheManager;
}

@Cacheable(value = "people#120#90", key = "#person.id")
public Person findOne(Person person) {
    Person p = personRepository.findOne(person.getId());
    System.out.println("為id、key為:" + p.getId() + "數(shù)據(jù)做了緩存");
    return p;
}

 
@Cacheable(value = "people#${select.cache.timeout:1800}#${select.cache.refresh:600}", key = "#person.id", sync = true)//3
public Person findOne(Person person) {
    Person p = personRepository.findOne(person.getId());
    System.out.println("為id、key為:" + p.getId() + "數(shù)據(jù)做了緩存");
    return p;
}

 
public interface CacheManager {
    /**
     * 根據(jù)名稱獲取一個(gè)Cache（在實(shí)現(xiàn)類里面是如果有這個(gè)Cache就返回，沒(méi)有就新建一個(gè)Cache放到Map容器中）
     * @param name the cache identifier (must not be {@code null})
     * @return the associated cache, or {@code null} if none found
     */
    Cache getCache(String name);
    /**
     * 返回一個(gè)緩存名稱的集合
     * @return the names of all caches known by the cache manager
     */
    Collection<String> getCacheNames();
}

 
public interface Cache {
    ValueWrapper get(Object key);
    void put(Object key, Object value);
    void evict(Object key);
    ...
}

// 設(shè)置默認(rèn)的時(shí)間
public void setDefaultExpiration(long defaultExpireTime) {
    this.defaultExpiration = defaultExpireTime;
}
// 根據(jù)特定名稱設(shè)置有效時(shí)間
public void setExpires(Map<String, Long> expires) {
    this.expires = (expires != null ? new ConcurrentHashMap<String, Long>(expires) : null);
}
// 獲取一個(gè)key的有效時(shí)間
protected long computeExpiration(String name) {
    Long expiration = null;
    if (expires != null) {
        expiration = expires.get(name);
    }
    return (expiration != null ? expiration.longValue() : defaultExpiration);
}
@SuppressWarnings("unchecked")
protected RedisCache createCache(String cacheName) {
    // 調(diào)用了上面的方法獲取緩存名稱的有效時(shí)間
    long expiration = computeExpiration(cacheName);
    // 創(chuàng)建了Cache對(duì)象，并使用了這個(gè)有效時(shí)間
    return new RedisCache(cacheName, (usePrefix ? cachePrefix.prefix(cacheName) : null), redisOperations, expiration,
            cacheNullValues);
}
// 重寫父類的getMissingCache。去創(chuàng)建Cache
@Override
protected Cache getMissingCache(String name) {
    return this.dynamic ? createCache(name) : null;
}

 
// 根據(jù)名稱獲取Cache如果沒(méi)有調(diào)用getMissingCache方法，生成新的Cache，并將其放到Map容器中去。
@Override
public Cache getCache(String name) {
    Cache cache = this.cacheMap.get(name);
    if (cache != null) {
        return cache;
    }
    else {
        // Fully synchronize now for missing cache creation...
        synchronized (this.cacheMap) {
            cache = this.cacheMap.get(name);
            if (cache == null) {
                // 如果沒(méi)找到Cache調(diào)用該方法，這個(gè)方法默認(rèn)返回值NULL由子類自己實(shí)現(xiàn)。上面的就是子類自己實(shí)現(xiàn)的方法
                cache = getMissingCache(name);
                if (cache != null) {
                    cache = decorateCache(cache);
                    this.cacheMap.put(name, cache);
                    updateCacheNames(name);
                }
            }
            return cache;
        }
    }
}

 
package com.xiaolyuh.redis.cache;
import com.xiaolyuh.redis.cache.helper.SpringContextHolder;
import com.xiaolyuh.redis.utils.ReflectionUtils;
import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.support.DefaultListableBeanFactory;
import org.springframework.cache.Cache;
import org.springframework.data.redis.cache.RedisCacheManager;
import org.springframework.data.redis.core.RedisOperations;
import java.util.Collection;
import java.util.concurrent.ConcurrentHashMap;
/**
 * 自定義的redis緩存管理器
 * 支持方法上配置過(guò)期時(shí)間
 * 支持熱加載緩存：緩存即將過(guò)期時(shí)主動(dòng)刷新緩存
 *
 * @author yuhao.wang
 */
public class CustomizedRedisCacheManager extends RedisCacheManager {
    private static final Logger logger = LoggerFactory.getLogger(CustomizedRedisCacheManager.class);
    /**
     * 父類cacheMap字段
     */
    private static final String SUPER_FIELD_CACHEMAP = "cacheMap";
    /**
     * 父類dynamic字段
     */
    private static final String SUPER_FIELD_DYNAMIC = "dynamic";
    /**
     * 父類cacheNullValues字段
     */
    private static final String SUPER_FIELD_CACHENULLVALUES = "cacheNullValues";
    /**
     * 父類updateCacheNames方法
     */
    private static final String SUPER_METHOD_UPDATECACHENAMES = "updateCacheNames";
    /**
     * 緩存參數(shù)的分隔符
     * 數(shù)組元素0=緩存的名稱
     * 數(shù)組元素1=緩存過(guò)期時(shí)間TTL
     * 數(shù)組元素2=緩存在多少秒開(kāi)始主動(dòng)失效來(lái)強(qiáng)制刷新
     */
    private static final String SEPARATOR = "#";
    /**
     * SpEL標(biāo)示符
     */
    private static final String MARK = "$";
    RedisCacheManager redisCacheManager = null;
    @Autowired
    DefaultListableBeanFactory beanFactory;
    public CustomizedRedisCacheManager(RedisOperations redisOperations) {
        super(redisOperations);
    }
    public CustomizedRedisCacheManager(RedisOperations redisOperations, Collection<String> cacheNames) {
        super(redisOperations, cacheNames);
    }
    public RedisCacheManager getInstance() {
        if (redisCacheManager == null) {
            redisCacheManager = SpringContextHolder.getBean(RedisCacheManager.class);
        }
        return redisCacheManager;
    }
    @Override
    public Cache getCache(String name) {
        String[] cacheParams = name.split(SEPARATOR);
        String cacheName = cacheParams[0];
        if (StringUtils.isBlank(cacheName)) {
            return null;
        }
        // 有效時(shí)間，初始化獲取默認(rèn)的有效時(shí)間
        Long expirationSecondTime = getExpirationSecondTime(cacheName, cacheParams);
        // 自動(dòng)刷新時(shí)間，默認(rèn)是0
        Long preloadSecondTime = getExpirationSecondTime(cacheParams);
        // 通過(guò)反射獲取父類存放緩存的容器對(duì)象
        Object object = ReflectionUtils.getFieldValue(getInstance(), SUPER_FIELD_CACHEMAP);
        if (object != null && object instanceof ConcurrentHashMap) {
            ConcurrentHashMap<String, Cache> cacheMap = (ConcurrentHashMap<String, Cache>) object;
            // 生成Cache對(duì)象，并將其保存到父類的Cache容器中
            return getCache(cacheName, expirationSecondTime, preloadSecondTime, cacheMap);
        } else {
            return super.getCache(cacheName);
        }
    }
    /**
     * 獲取過(guò)期時(shí)間
     *
     * @return
     */
    private long getExpirationSecondTime(String cacheName, String[] cacheParams) {
        // 有效時(shí)間，初始化獲取默認(rèn)的有效時(shí)間
        Long expirationSecondTime = this.computeExpiration(cacheName);
        // 設(shè)置key有效時(shí)間
        if (cacheParams.length > 1) {
            String expirationStr = cacheParams[1];
            if (!StringUtils.isEmpty(expirationStr)) {
                // 支持配置過(guò)期時(shí)間使用EL表達(dá)式讀取配置文件時(shí)間
                if (expirationStr.contains(MARK)) {
                    expirationStr = beanFactory.resolveEmbeddedValue(expirationStr);
                }
                expirationSecondTime = Long.parseLong(expirationStr);
            }
        }
        return expirationSecondTime;
    }
    /**
     * 獲取自動(dòng)刷新時(shí)間
     *
     * @return
     */
    private long getExpirationSecondTime(String[] cacheParams) {
        // 自動(dòng)刷新時(shí)間，默認(rèn)是0
        Long preloadSecondTime = 0L;
        // 設(shè)置自動(dòng)刷新時(shí)間
        if (cacheParams.length > 2) {
            String preloadStr = cacheParams[2];
            if (!StringUtils.isEmpty(preloadStr)) {
                // 支持配置刷新時(shí)間使用EL表達(dá)式讀取配置文件時(shí)間
                if (preloadStr.contains(MARK)) {
                    preloadStr = beanFactory.resolveEmbeddedValue(preloadStr);
                }
                preloadSecondTime = Long.parseLong(preloadStr);
            }
        }
        return preloadSecondTime;
    }
    /**
     * 重寫父類的getCache方法，真假了三個(gè)參數(shù)
     *
     * @param cacheName            緩存名稱
     * @param expirationSecondTime 過(guò)期時(shí)間
     * @param preloadSecondTime    自動(dòng)刷新時(shí)間
     * @param cacheMap             通過(guò)反射獲取的父類的cacheMap對(duì)象
     * @return Cache
     */
    public Cache getCache(String cacheName, long expirationSecondTime, long preloadSecondTime, ConcurrentHashMap<String, Cache> cacheMap) {
        Cache cache = cacheMap.get(cacheName);
        if (cache != null) {
            return cache;
        } else {
            // Fully synchronize now for missing cache creation...
            synchronized (cacheMap) {
                cache = cacheMap.get(cacheName);
                if (cache == null) {
                    // 調(diào)用我們自己的getMissingCache方法創(chuàng)建自己的cache
                    cache = getMissingCache(cacheName, expirationSecondTime, preloadSecondTime);
                    if (cache != null) {
                        cache = decorateCache(cache);
                        cacheMap.put(cacheName, cache);
                        // 反射去執(zhí)行父類的updateCacheNames(cacheName)方法
                        Class<?>[] parameterTypes = {String.class};
                        Object[] parameters = {cacheName};
                        ReflectionUtils.invokeMethod(getInstance(), SUPER_METHOD_UPDATECACHENAMES, parameterTypes, parameters);
                    }
                }
                return cache;
            }
        }
    }
    /**
     * 創(chuàng)建緩存
     *
     * @param cacheName            緩存名稱
     * @param expirationSecondTime 過(guò)期時(shí)間
     * @param preloadSecondTime    制動(dòng)刷新時(shí)間
     * @return
     */
    public CustomizedRedisCache getMissingCache(String cacheName, long expirationSecondTime, long preloadSecondTime) {
        logger.info("緩存 cacheName：{}，過(guò)期時(shí)間:{}, 自動(dòng)刷新時(shí)間:{}", cacheName, expirationSecondTime, preloadSecondTime);
        Boolean dynamic = (Boolean) ReflectionUtils.getFieldValue(getInstance(), SUPER_FIELD_DYNAMIC);
        Boolean cacheNullValues = (Boolean) ReflectionUtils.getFieldValue(getInstance(), SUPER_FIELD_CACHENULLVALUES);
        return dynamic ? new CustomizedRedisCache(cacheName, (this.isUsePrefix() ? this.getCachePrefix().prefix(cacheName) : null),
                this.getRedisOperations(), expirationSecondTime, preloadSecondTime, cacheNullValues) : null;
    }
}

 
/**
 * 緩存主動(dòng)在失效前強(qiáng)制刷新緩存的時(shí)間
 * 單位：秒
 */
private long preloadSecondTime = 0;
// 重寫后的構(gòu)造方法
public CustomizedRedisCache(String name, byte[] prefix, RedisOperations<? extends Object, ? extends Object> redisOperations, long expiration, long preloadSecondTime) {
    super(name, prefix, redisOperations, expiration);
    this.redisOperations = redisOperations;
    // 指定自動(dòng)刷新時(shí)間
    this.preloadSecondTime = preloadSecondTime;
    this.prefix = prefix;
}
// 重寫后的構(gòu)造方法
public CustomizedRedisCache(String name, byte[] prefix, RedisOperations<? extends Object, ? extends Object> redisOperations, long expiration, long preloadSecondTime, boolean allowNullValues) {
    super(name, prefix, redisOperations, expiration, allowNullValues);
    this.redisOperations = redisOperations;
    // 指定自動(dòng)刷新時(shí)間
    this.preloadSecondTime = preloadSecondTime;
    this.prefix = prefix;
}

 
/**
 * 重寫get方法，獲取到緩存后再次取緩存剩余的時(shí)間，如果時(shí)間小余我們配置的刷新時(shí)間就手動(dòng)刷新緩存。
 * 為了不影響get的性能，啟用后臺(tái)線程去完成緩存的刷。
 * 并且只放一個(gè)線程去刷新數(shù)據(jù)。
 *
 * @param key
 * @return
 */
@Override
public ValueWrapper get(final Object key) {
    RedisCacheKey cacheKey = getRedisCacheKey(key);
    String cacheKeyStr = new String(cacheKey.getKeyBytes());
    // 調(diào)用重寫后的get方法
    ValueWrapper valueWrapper = this.get(cacheKey);
    if (null != valueWrapper) {
        // 刷新緩存數(shù)據(jù)
        refreshCache(key, cacheKeyStr);
    }
    return valueWrapper;
}
/**
 * 重寫父類的get函數(shù)。
 * 父類的get方法，是先使用exists判斷key是否存在，不存在返回null，存在再到redis緩存中去取值。這樣會(huì)導(dǎo)致并發(fā)問(wèn)題，
 * 假如有一個(gè)請(qǐng)求調(diào)用了exists函數(shù)判斷key存在，但是在下一時(shí)刻這個(gè)緩存過(guò)期了，或者被刪掉了。
 * 這時(shí)候再去緩存中獲取值的時(shí)候返回的就是null了。
 * 可以先獲取緩存的值，再去判斷key是否存在。
 *
 * @param cacheKey
 * @return
 */
@Override
public RedisCacheElement get(final RedisCacheKey cacheKey) {
    Assert.notNull(cacheKey, "CacheKey must not be null!");
    // 根據(jù)key獲取緩存值
    RedisCacheElement redisCacheElement = new RedisCacheElement(cacheKey, fromStoreValue(lookup(cacheKey)));
    // 判斷key是否存在
    Boolean exists = (Boolean) redisOperations.execute(new RedisCallback<Boolean>() {
        @Override
        public Boolean doInRedis(RedisConnection connection) throws DataAccessException {
            return connection.exists(cacheKey.getKeyBytes());
        }
    });
    if (!exists.booleanValue()) {
        return null;
    }
    return redisCacheElement;
}
/**
 * 刷新緩存數(shù)據(jù)
 */
private void refreshCache(Object key, String cacheKeyStr) {
    Long ttl = this.redisOperations.getExpire(cacheKeyStr);
    if (null != ttl && ttl <= CustomizedRedisCache.this.preloadSecondTime) {
        // 盡量少的去開(kāi)啟線程，因?yàn)榫€程池是有限的
        ThreadTaskHelper.run(new Runnable() {
            @Override
            public void run() {
                // 加一個(gè)分布式鎖，只放一個(gè)請(qǐng)求去刷新緩存
                RedisLock redisLock = new RedisLock((RedisTemplate) redisOperations, cacheKeyStr + "_lock");
                try {
                    if (redisLock.lock()) {
                        // 獲取鎖之后再判斷一下過(guò)期時(shí)間，看是否需要加載數(shù)據(jù)
                        Long ttl = CustomizedRedisCache.this.redisOperations.getExpire(cacheKeyStr);
                        if (null != ttl && ttl <= CustomizedRedisCache.this.preloadSecondTime) {
                            // 通過(guò)獲取代理方法信息重新加載緩存數(shù)據(jù)
                            CustomizedRedisCache.this.getCacheSupport().refreshCacheByKey(CustomizedRedisCache.super.getName(), key.toString());
                        }
                    }
                } catch (Exception e) {
                    logger.info(e.getMessage(), e);
                } finally {
                    redisLock.unlock();
                }
            }
        });
    }
}

 
public final class CachedInvocation {
    private Object key;
    private final Object targetBean;
    private final Method targetMethod;
    private Object[] arguments;
    public CachedInvocation(Object key, Object targetBean, Method targetMethod, Object[] arguments) {
        this.key = key;
        this.targetBean = targetBean;
        this.targetMethod = targetMethod;
        if (arguments != null && arguments.length != 0) {
            this.arguments = Arrays.copyOf(arguments, arguments.length);
        }
    }
    public Object[] getArguments() {
        return arguments;
    }
    public Object getTargetBean() {
        return targetBean;
    }
    public Method getTargetMethod() {
        return targetMethod;
    }
    public Object getKey() {
        return key;
    }
    /**
     * 必須重寫equals和hashCode方法，否則放到set集合里沒(méi)法去重
     * @param o
     * @return
     */
    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }
        CachedInvocation that = (CachedInvocation) o;
        return key.equals(that.key);
    }
    @Override
    public int hashCode() {
        return key.hashCode();
    }
}

 
private final String SEPARATOR = "#";
/**
 * 記錄緩存執(zhí)行方法信息的容器。
 * 如果有很多無(wú)用的緩存數(shù)據(jù)的話，有可能會(huì)照成內(nèi)存溢出。
 */
private Map<String, Set<CachedInvocation>> cacheToInvocationsMap = new ConcurrentHashMap<>();
@Autowired
private CacheManager cacheManager;
// 刷新緩存
private void refreshCache(CachedInvocation invocation, String cacheName) {
    boolean invocationSuccess;
    Object computed = null;
    try {
        // 通過(guò)代理調(diào)用方法，并記錄返回值
        computed = invoke(invocation);
        invocationSuccess = true;
    } catch (Exception ex) {
        invocationSuccess = false;
    }
    if (invocationSuccess) {
        if (!CollectionUtils.isEmpty(cacheToInvocationsMap.get(cacheName))) {
            // 通過(guò)cacheManager獲取操作緩存的cache對(duì)象
            Cache cache = cacheManager.getCache(cacheName);
            // 通過(guò)Cache對(duì)象更新緩存
            cache.put(invocation.getKey(), computed);
        }
    }
}
private Object invoke(CachedInvocation invocation)
        throws ClassNotFoundException, NoSuchMethodException, InvocationTargetException, IllegalAccessException {
    final MethodInvoker invoker = new MethodInvoker();
    invoker.setTargetObject(invocation.getTargetBean());
    invoker.setArguments(invocation.getArguments());
    invoker.setTargetMethod(invocation.getTargetMethod().getName());
    invoker.prepare();
    return invoker.invoke();
}
// 注冊(cè)緩存方法的執(zhí)行類信息
@Override
public void registerInvocation(Object targetBean, Method targetMethod, Object[] arguments,
        Set<String> annotatedCacheNames, String cacheKey) {
    // 獲取注解上真實(shí)的value值
    Collection<String> cacheNames = generateValue(annotatedCacheNames);
    // 獲取注解上的key屬性值
    Class<?> targetClass = getTargetClass(targetBean);
    Collection<? extends Cache> caches = getCache(cacheNames);
    Object key = generateKey(caches, cacheKey, targetMethod, arguments, targetBean, targetClass,
            CacheOperationExpressionEvaluator.NO_RESULT);
    // 新建一個(gè)代理對(duì)象（記錄了緩存注解的方法類信息）
    final CachedInvocation invocation = new CachedInvocation(key, targetBean, targetMethod, arguments);
    for (final String cacheName : cacheNames) {
        if (!cacheToInvocationsMap.containsKey(cacheName)) {
            cacheToInvocationsMap.put(cacheName, new CopyOnWriteArraySet<>());
        }
        cacheToInvocationsMap.get(cacheName).add(invocation);
    }
}
@Override
public void refreshCache(String cacheName) {
    this.refreshCacheByKey(cacheName, null);
}
// 刷新特定key緩存
@Override
public void refreshCacheByKey(String cacheName, String cacheKey) {
    // 如果根據(jù)緩存名稱沒(méi)有找到代理信息類的set集合就不執(zhí)行刷新操作。
    // 只有等緩存有效時(shí)間過(guò)了，再走到切面哪里然后把代理方法信息注冊(cè)到這里來(lái)。
    if (!CollectionUtils.isEmpty(cacheToInvocationsMap.get(cacheName))) {
        for (final CachedInvocation invocation : cacheToInvocationsMap.get(cacheName)) {
            if (!StringUtils.isBlank(cacheKey) && invocation.getKey().toString().equals(cacheKey)) {
                logger.info("緩存：{}-{}，重新加載數(shù)據(jù)", cacheName, cacheKey.getBytes());
                refreshCache(invocation, cacheName);
            }
        }
    }
}

 
/**
 * 緩存攔截，用于注冊(cè)方法信息
 * @author yuhao.wang
 */
@Aspect
@Component
public class CachingAnnotationsAspect {
    private static final Logger logger = LoggerFactory.getLogger(CachingAnnotationsAspect.class);
    @Autowired
    private InvocationRegistry cacheRefreshSupport;
    private <T extends Annotation> List<T> getMethodAnnotations(AnnotatedElement ae, Class<T> annotationType) {
        List<T> anns = new ArrayList<T>(2);
        // look for raw annotation
        T ann = ae.getAnnotation(annotationType);
        if (ann != null) {
            anns.add(ann);
        }
        // look for meta-annotations
        for (Annotation metaAnn : ae.getAnnotations()) {
            ann = metaAnn.annotationType().getAnnotation(annotationType);
            if (ann != null) {
                anns.add(ann);
            }
        }
        return (anns.isEmpty() ? null : anns);
    }
    private Method getSpecificmethod(ProceedingJoinPoint pjp) {
        MethodSignature methodSignature = (MethodSignature) pjp.getSignature();
        Method method = methodSignature.getMethod();
        // The method may be on an interface, but we need attributes from the
        // target class. If the target class is null, the method will be
        // unchanged.
        Class<?> targetClass = AopProxyUtils.ultimateTargetClass(pjp.getTarget());
        if (targetClass == null && pjp.getTarget() != null) {
            targetClass = pjp.getTarget().getClass();
        }
        Method specificMethod = ClassUtils.getMostSpecificMethod(method, targetClass);
        // If we are dealing with method with generic parameters, find the
        // original method.
        specificMethod = BridgeMethodResolver.findBridgedMethod(specificMethod);
        return specificMethod;
    }
    @Pointcut("@annotation(org.springframework.cache.annotation.Cacheable)")
    public void pointcut() {
    }
    @Around("pointcut()")
    public Object registerInvocation(ProceedingJoinPoint joinPoint) throws Throwable {
        Method method = this.getSpecificmethod(joinPoint);
        List<Cacheable> annotations = this.getMethodAnnotations(method, Cacheable.class);
        Set<String> cacheSet = new HashSet<String>();
        String cacheKey = null;
        for (Cacheable cacheables : annotations) {
            cacheSet.addAll(Arrays.asList(cacheables.value()));
            cacheKey = cacheables.key();
        }
        cacheRefreshSupport.registerInvocation(joinPoint.getTarget(), method, joinPoint.getArgs(), cacheSet, cacheKey);
        return joinPoint.proceed();
    }
}