006-spring cache-缓存原理-SimpleCacheConfiguration、RedisCacheConfiguration原理实现

一、实现说明

事务回滚：除了GuavaCacheManager之外，其他Cache都支持Spring事务，即如果事务回滚了，缓存的数据也会移除掉。

Spring不进行cache的定义，也不进行Cache的缓存策略的维护。这些都是由底层cache自己实现，然后外部创建一个cache注入进来的。Spring只是提供了一个Wrapper，提供一套对外一致的API。

CacheManger	描述
SimpleCacheManager	使用简单的Collection来存储缓存，主要用于测试
ConcurrentMapCacheManager	使用ConcurrentMap作为缓存技术（默认）
NoOpCacheManager	测试用
EhCacheCacheManager	使用EhCache作为缓存技术，以前在hibernate的时候经常用
GuavaCacheManager	使用google guava的GuavaCache作为缓存技术
HazelcastCacheManager	使用Hazelcast作为缓存技术
JCacheCacheManager	使用JCache标准的实现作为缓存技术，如Apache Commons JCS
RedisCacheManager	使用Redis作为缓存技术

springboot cache

    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);
    }

　　Spring boot默认使用的是SimpleCacheConfiguration，即使用ConcurrentMapCacheManager来实现缓存。

二、CacheManager说明

2.1、SimpleCacheConfiguration 说明

核心UML图

　　

查看ConcurrentMapCache实现 核心是ValueWrapper

　　

2.1.1、SimpleCacheConfiguration说明实现

代码地址：https://github.com/bjlhx15/common.git spring-cache/springboot2-cache-default

2.1.2、基础配置

参看：001-spring cache 简介、基础使用

2.2、RedisCacheConfiguration说明 

　　  

1、RedisCacheConfiguration

　　配置类配置缓存管理器

/*
 * Copyright 2012-2018 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.boot.autoconfigure.cache;

import java.util.LinkedHashSet;
import java.util.List;

import org.springframework.beans.factory.ObjectProvider;
import org.springframework.boot.autoconfigure.AutoConfigureAfter;
import org.springframework.boot.autoconfigure.cache.CacheProperties.Redis;
import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.boot.autoconfigure.data.redis.RedisAutoConfiguration;
import org.springframework.cache.CacheManager;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Conditional;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.ResourceLoader;
import org.springframework.data.redis.cache.RedisCacheManager;
import org.springframework.data.redis.cache.RedisCacheManager.RedisCacheManagerBuilder;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.serializer.JdkSerializationRedisSerializer;
import org.springframework.data.redis.serializer.RedisSerializationContext.SerializationPair;

/**
 * Redis cache configuration.
 *
 * @author Stephane Nicoll
 * @author Mark Paluch
 * @author Ryon Day
 * @since 1.3.0
 */
@Configuration
@ConditionalOnClass(RedisConnectionFactory.class)
@AutoConfigureAfter(RedisAutoConfiguration.class)
@ConditionalOnBean(RedisConnectionFactory.class)
@ConditionalOnMissingBean(CacheManager.class)
@Conditional(CacheCondition.class)
class RedisCacheConfiguration {

    private final CacheProperties cacheProperties;

    private final CacheManagerCustomizers customizerInvoker;

    private final org.springframework.data.redis.cache.RedisCacheConfiguration redisCacheConfiguration;

    RedisCacheConfiguration(CacheProperties cacheProperties,
            CacheManagerCustomizers customizerInvoker,
            ObjectProvider<org.springframework.data.redis.cache.RedisCacheConfiguration> redisCacheConfiguration) {
        this.cacheProperties = cacheProperties;
        this.customizerInvoker = customizerInvoker;
        this.redisCacheConfiguration = redisCacheConfiguration.getIfAvailable();
    }

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

    private org.springframework.data.redis.cache.RedisCacheConfiguration determineConfiguration(
            ClassLoader classLoader) {
        if (this.redisCacheConfiguration != null) {
            return this.redisCacheConfiguration;
        }
        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;
    }

}

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