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CacheManager个性化设置

• 可以根据需要，让某些key，默认TTL与基础设置不同，直接看代码
  这不是重点，只是可以提前DIY一些东西

@Bean    public CacheManager cacheManager(RedisConnectionFactory redisConnectionFactory) {
           // 配置序列化        // 统一默认配置，TTL为60秒        RedisCacheConfiguration config = RedisCacheConfiguration.defaultCacheConfig()                .entryTtl(Duration.ofSeconds(60));        // 针对不同key可以个性化设置        Set
   
     cacheNames = new HashSet<>();        cacheNames.add("account");        cacheNames.add("post");        // 对每个缓存空间应用不同的配置        Map
    
      configMap = new HashMap<>();        configMap.put("account", config.entryTtl(Duration.ofSeconds(30)));        configMap.put("post", config);        return RedisCacheManager.builder(redisConnectionFactory)                .cacheDefaults(config)                .initialCacheNames(cacheNames)                .withInitialCacheConfigurations(configMap)                .build();    }
    
   

自定义每个缓存的TTL和自动刷新

上面的设置虽然可以提前设定每个cacheName的ttl，但是不够细，虽然Cacheable的sync可以防止缓存击穿，但是无法防止缓存雪崩。

我们可以使用AOP来完成自动刷新和自定义TTL。

代码写的比较糙，只是个例子，可以自己修改。

自己写TTL注解

import org.springframework.core.annotation.AliasFor;import java.lang.annotation.*;@Retention(RetentionPolicy.RUNTIME)@Target(ElementType.METHOD)@Inheritedpublic @interface CacheTTL {
       @AliasFor("ttl")    long value() default 60;    @AliasFor("value")    long ttl() default 60;    long preExpireRefresh() default 10;}

AOP实现

import org.aspectj.lang.JoinPoint;import org.aspectj.lang.annotation.After;import org.aspectj.lang.annotation.Aspect;import org.aspectj.lang.reflect.MethodSignature;import org.springframework.cache.annotation.Cacheable;import org.springframework.cache.interceptor.SimpleKeyGenerator;import org.springframework.core.annotation.AnnotationUtils;import org.springframework.core.annotation.Order;import org.springframework.data.redis.core.RedisTemplate;import org.springframework.stereotype.Component;import java.lang.reflect.Method;import java.util.Arrays;import java.util.concurrent.TimeUnit;import java.util.concurrent.atomic.AtomicInteger;//这里必须要比Cacheable的Aspect优先级要高@Order(value=1)@Aspect@Componentpublic class CustomCacheAspect {
       private final RedisTemplate
   
     redisTemplate;    private final SimpleKeyGenerator keyGenerator =  new SimpleKeyGenerator();    private final AtomicInteger asyncLock = new AtomicInteger(0);    public CustomCacheAspect(RedisTemplate
    
      redisTemplate) {
           this.redisTemplate = redisTemplate;    }    @After(value="execution(* *..*.*(..))")    public void after(JoinPoint point)    {
           Object target = point.getTarget();        MethodSignature signature = (MethodSignature) point.getSignature();        Method method = signature.getMethod();        try {
               if (method.isAnnotationPresent(CacheTTL.class) && method.isAnnotationPresent(Cacheable.class)) {
                   CacheTTL ttlData = AnnotationUtils.getAnnotation(method, CacheTTL.class);                Cacheable cacheAbleData = AnnotationUtils.getAnnotation(method, Cacheable.class);                long ttl = ttlData.ttl();                long preExpireRefresh = ttlData.preExpireRefresh();                String[] cacheNames = cacheAbleData.cacheNames();                //默认的keyGenerator生成，如果自定义了自己改一下                Object key = keyGenerator.generate(target, method, point.getArgs());                                updateExpire(cacheNames,key,preExpireRefresh,ttl);            }        } catch (Exception e) {
               e.printStackTrace();        }    }    public void updateExpire(String[] cacheNames,Object key,long preExpireRefresh,long ttl){
           if (asyncLock.compareAndSet(0,1)){
               Arrays.stream(cacheNames).parallel().forEach(cacheName->{
                   cacheName = cacheName + "::" + key;                long expire = redisTemplate.getExpire(cacheName,TimeUnit.SECONDS);                if (expire>0 && expire<=preExpireRefresh || expire > ttl || expire == -1){
                       redisTemplate.expire(cacheName, ttl, TimeUnit.SECONDS);                }            });            asyncLock.set(0);        }    }}
    
   

使用

@Cacheable(cacheNames = "account",key="#id",sync = true)    @CacheTTL(ttl = 60,preExpireRefresh = 10)    public Account findAccountByID(int id) {
           return accountDao.findAccountByID(id);    }

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