SpringBoot 缓存工作原理

1. 自动配置类：CacheAutoConfiguration

2. 缓存的配置类：

org.springframework.boot.autoconfigure.cache.GenericCacheConfiguration
org.springframework.boot.autoconfigure.cache.JCacheCacheConfiguration
org.springframework.boot.autoconfigure.cache.EhCacheCacheConfiguration
org.springframework.boot.autoconfigure.cache.HazelcastCacheConfiguration
org.springframework.boot.autoconfigure.cache.InfinispanCacheConfiguration
org.springframework.boot.autoconfigure.cache.CouchbaseCacheConfiguration
org.springframework.boot.autoconfigure.cache.RedisCacheConfiguration
org.springframework.boot.autoconfigure.cache.CaffeineCacheConfiguration
org.springframework.boot.autoconfigure.cache.SimpleCacheConfiguration
org.springframework.boot.autoconfigure.cache.NoOpCacheConfiguration

3. 默认生效的是SimpleCacheConfiguration

@Configuration(proxyBeanMethods = false)
@ConditionalOnMissingBean(CacheManager.class)
@Conditional(CacheCondition.class)
class SimpleCacheConfiguration {

    @Bean
    ConcurrentMapCacheManager cacheManager(CacheProperties cacheProperties,
            CacheManagerCustomizers cacheManagerCustomizers) {
        ConcurrentMapCacheManager cacheManager = new ConcurrentMapCacheManager();
        List<String> cacheNames = cacheProperties.getCacheNames();
        if (!cacheNames.isEmpty()) {
            cacheManager.setCacheNames(cacheNames);
        }
        return cacheManagerCustomizers.customize(cacheManager);
    }

}

4. 给容器中注册了一个CacheManager：ConcurrentMapCacheManager 

5. 可以获取和创建ConcurrentMapCache类型的缓存组件：将数据保存在ConcurrentMap中