搭建Caffeine+Redis多级缓存机制

<!-- Caffeine 本地缓存 -->
<dependency>
	<groupId>com.github.ben-manes.caffeine</groupId>
	<artifactId>caffeine</artifactId>
</dependency>

<!-- 缓存抽象层 -->
<dependency>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-starter-cache</artifactId>
</dependency>

<!-- redis 缓存操作 -->
<dependency>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-starter-data-redis</artifactId>
	   <exclusions>
		 <exclusion>
			 <groupId>io.lettuce</groupId>
			 <artifactId>lettuce-core</artifactId>
		 </exclusion>
		</exclusions>
</dependency>

<dependency>
 <groupId>redis.clients</groupId>
 <artifactId>jedis</artifactId>
</dependency>

spring: 
 cache:
    caffeine:
      spec: maximumSize=1000,expireAfterWrite=10m  # 本地缓存
    redis:
      time-to-live: 1h  # Redis缓存过期时间
  # redis 配置
  redis:
    # 地址
    host: 127.0.0.1
    # 端口，默认为6379
    port: 6379
    # 数据库索引
    database: 0
    # 密码
    password: abc123
    # 连接超时时间
    timeout: 6000ms  # 连接超时时长（毫秒）
    jedis:
      pool:
        max-active: 1000  # 连接池最大连接数（使用负值表示没有限制）
        max-wait: -1ms      # 连接池最大阻塞等待时间（使用负值表示没有限制）
        max-idle: 10      # 连接池中的最大空闲连接
        min-idle: 5       # 连接池中的最小空闲连接

import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.autoconfigure.cache.CacheProperties;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.cache.CacheManager;
import org.springframework.cache.annotation.EnableCaching;
import org.springframework.cache.caffeine.CaffeineCacheManager;
import org.springframework.cache.support.CompositeCacheManager;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.data.redis.cache.RedisCacheConfiguration;
import org.springframework.data.redis.cache.RedisCacheManager;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.serializer.GenericJackson2JsonRedisSerializer;
import org.springframework.data.redis.serializer.RedisSerializationContext;
import org.springframework.data.redis.serializer.StringRedisSerializer;
import com.github.benmanes.caffeine.cache.Caffeine;

import java.util.concurrent.TimeUnit;


@Configuration
@EnableCaching
@EnableConfigurationProperties(CacheProperties.class)
public class MyCacheConfig {

    @Bean
    public RedisCacheConfiguration cacheConfiguration(CacheProperties cacheProperties) {
        RedisCacheConfiguration config = RedisCacheConfiguration.defaultCacheConfig();
        config = config.serializeKeysWith(RedisSerializationContext.SerializationPair.fromSerializer(new StringRedisSerializer()));
        config = config.serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer(new GenericJackson2JsonRedisSerializer()));

        CacheProperties.Redis redisProperties = 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;
    }

    @Bean
    public Caffeine<Object, Object> caffeineConfig() {
        return Caffeine.newBuilder()
                .maximumSize(1000)
                .expireAfterWrite(10, TimeUnit.MINUTES);
    }

    @Bean
    @Primary  // 添加 @Primary 注解指定 CaffeineCacheManager 作为默认的缓存管理器
    public CacheManager caffeineCacheManager(Caffeine<Object, Object> caffeine) {
        CaffeineCacheManager manager = new CaffeineCacheManager();
        manager.setCaffeine(caffeine);
        return manager;
    }

    @Bean
    public RedisCacheManager redisCacheManager(
            RedisConnectionFactory redisConnectionFactory,
            RedisCacheConfiguration cacheConfiguration) {

        return RedisCacheManager.builder(redisConnectionFactory)
                .cacheDefaults(cacheConfiguration)
                .build();
    }

    @Bean
    public CacheManager compositeCacheManager(
            @Qualifier("caffeineCacheManager") CacheManager caffeineCacheManager,
            @Qualifier("redisCacheManager") CacheManager redisCacheManager) {

        return new CompositeCacheManager(
                caffeineCacheManager,
                redisCacheManager
        );
    }
}
        

@Service
public class ProductService {

    @Autowired
    private ProductRepository repository;

    // 优先读本地缓存，其次Redis，最后数据库
    @Cacheable(cacheNames = "product", key = "#id")
    public Product getProductById(Long id) {
        return repository.findById(id).orElseThrow();
    }

    // 更新数据时清除两级缓存
    @CacheEvict(cacheNames = "product", key = "#product.id")
    public Product updateProduct(Product product) {
        return repository.save(product);
    }
}

@Service
public class CacheService {

    @Autowired
    private CacheManager cacheManager;

    @Autowired
    private RedisTemplate<String, Object> redisTemplate;

    public Product getProductWithManualControl(Long id) {
        // 1. 先查本地缓存
        Cache caffeineCache = cacheManager.getCache("product");
        Product product = caffeineCache.get(id, Product.class);
        if (product != null) {
            return product;
        }

        // 2. 查Redis缓存
        product = (Product) redisTemplate.opsForValue().get("product:" + id);
        if (product != null) {
            // 回填本地缓存
            caffeineCache.put(id, product);
            return product;
        }

        // 3. 查数据库
        product = repository.findById(id).orElseThrow();
        
        // 回填两级缓存
        redisTemplate.opsForValue().set("product:" + id, product, Duration.ofHours(1));
        caffeineCache.put(id, product);
        
        return product;
    }
}

Caffeine.newBuilder()
    .refreshAfterWrite(5, TimeUnit.MINUTES)
    .build(key -> loadFromRedisOrDb(key));