SpringCache

目录

SpringCache

引入

自动配置

自定义配置

注解 

@Cacheable

@CacheEvict​​

sync = true

---

SpringCache

集成与管理缓存，它通过声明式注解和统一的 API，将缓存逻辑与业务逻辑解耦，支持多种缓存实现（如 Redis、Ehcache、Caffeine 等），并提供了灵活的配置选项。

引入

        <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-cache</artifactId></dependency>

@EnableCaching开启缓存

自动配置

CacheAutoConfiguration 依据缓存类型，自动配置缓存。

CacheConfigurations 映射 相应的缓存配置

    static {Map<CacheType, Class<?>> mappings = new EnumMap(CacheType.class);mappings.put(CacheType.GENERIC, GenericCacheConfiguration.class);mappings.put(CacheType.EHCACHE, EhCacheCacheConfiguration.class);mappings.put(CacheType.HAZELCAST, HazelcastCacheConfiguration.class);mappings.put(CacheType.INFINISPAN, InfinispanCacheConfiguration.class);mappings.put(CacheType.JCACHE, JCacheCacheConfiguration.class);mappings.put(CacheType.COUCHBASE, CouchbaseCacheConfiguration.class);mappings.put(CacheType.REDIS, RedisCacheConfiguration.class);mappings.put(CacheType.CAFFEINE, CaffeineCacheConfiguration.class);mappings.put(CacheType.SIMPLE, SimpleCacheConfiguration.class);mappings.put(CacheType.NONE, NoOpCacheConfiguration.class);MAPPINGS = Collections.unmodifiableMap(mappings);}

RedisCacheConfiguration 为每一个缓存"分区" 提供初始化，并返回Manager

    @Beanpublic RedisCacheManager cacheManager(RedisConnectionFactory redisConnectionFactory, ResourceLoader resourceLoader) {RedisCacheManager.RedisCacheManagerBuilder builder = RedisCacheManager.builder(redisConnectionFactory).cacheDefaults(this.determineConfiguration(resourceLoader.getClassLoader()));List<String> cacheNames = this.cacheProperties.getCacheNames();if (!cacheNames.isEmpty()) {builder.initialCacheNames(new LinkedHashSet(cacheNames));}return (RedisCacheManager)this.customizerInvoker.customize(builder.build());}

Manager为每一个分区进行默认配置defaultCacheConfiguration

        public RedisCacheManagerBuilder initialCacheNames(Set<String> cacheNames) {Assert.notNull(cacheNames, "CacheNames must not be null!");Map<String, RedisCacheConfiguration> cacheConfigMap = new LinkedHashMap(cacheNames.size());cacheNames.forEach((it) -> {RedisCacheConfiguration var10000 = (RedisCacheConfiguration)cacheConfigMap.put(it, this.defaultCacheConfiguration);});return this.withInitialCacheConfigurations(cacheConfigMap);}

redisCacheConfiguration 若为空，这采用默认配置

    private org.springframework.data.redis.cache.RedisCacheConfiguration determineConfiguration(ClassLoader classLoader) {if (this.redisCacheConfiguration != null) {return this.redisCacheConfiguration;} else {CacheProperties.Redis redisProperties = this.cacheProperties.getRedis();org.springframework.data.redis.cache.RedisCacheConfiguration config = org.springframework.data.redis.cache.RedisCacheConfiguration.defaultCacheConfig();config = config.serializeValuesWith(SerializationPair.fromSerializer(new JdkSerializationRedisSerializer(classLoader)));if (redisProperties.getTimeToLive() != null) {config = config.entryTtl(redisProperties.getTimeToLive());}if (redisProperties.getKeyPrefix() != null) {config = config.prefixKeysWith(redisProperties.getKeyPrefix());}if (!redisProperties.isCacheNullValues()) {config = config.disableCachingNullValues();}if (!redisProperties.isUseKeyPrefix()) {config = config.disableKeyPrefix();}return config;}}

自定义配置

容器中注入一个 RedisCacheConfiguration

@EnableCaching
@Configuration
public class MyCacheConfig {@Autowiredprivate CacheProperties cacheProperties;@BeanRedisCacheConfiguration redisCacheConfiguration(){RedisCacheConfiguration config = RedisCacheConfiguration.defaultCacheConfig();config = config.serializeKeysWith(RedisSerializationContext.SerializationPair.fromSerializer(new StringRedisSerializer()));//Json序列化config = config.serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer(new GenericFastJsonRedisSerializer()));//使配置文件生效CacheProperties.Redis redisProperties = this.cacheProperties.getRedis();if (redisProperties.getTimeToLive() != null) {config = config.entryTtl(redisProperties.getTimeToLive());}if (redisProperties.getKeyPrefix() != null) {config = config.prefixKeysWith(redisProperties.getKeyPrefix());}if (!redisProperties.isCacheNullValues()) {config = config.disableCachingNullValues();}if (!redisProperties.isUseKeyPrefix()) {config = config.disableKeyPrefix();}return config;}
}

spring.cache.type=redis#缓存空值，防止缓存穿透
spring.cache.redis.cache-null-values=true
#spring.cache.redis.time-to-live=3600000
#spring.cache.redis.key-prefix=CACHE_
spring.cache.redis.use-key-prefix=true

---

注解 

@Cacheable

缓存方法返回值，若缓存命中则直接返回结果，否则执行方法并缓存结果。

键名 默认格式 缓存名::SimpleKey[param1, param2,...]，支持 SpEL 表达式

@Cacheable(key = "#id")                 // 使用参数 id 作为键
@Cacheable(key = "#user.id")           // 使用对象属性作为键
@Cacheable(key = "#root.methodName")   // 使用方法名作为键[1,3](@ref)

默认使用jdk序列化机制，可在自定义配置中使用Json序列化器

@CacheEvict​​

清除缓存数据

sync = true

 同步锁，本地锁，仅@Cacheable支持

@Cacheable(cacheNames = "category",key = "#root.methodName",sync = true)