起步依赖

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

SpringCacheConfig

同时配置带过期时间的CacheManager

自定义Json序列化方式存储

import cn.hutool.core.util.RandomUtil;
import com.fasterxml.jackson.annotation.JsonAutoDetect;
import com.fasterxml.jackson.annotation.JsonTypeInfo;
import com.fasterxml.jackson.annotation.PropertyAccessor;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.databind.jsontype.impl.LaissezFaireSubTypeValidator;
import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
import org.springframework.context.annotation.Bean;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.cache.RedisCacheConfiguration;
import org.springframework.cache.CacheManager;
import org.springframework.cache.support.NoOpCacheManager;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.serializer.Jackson2JsonRedisSerializer;
import org.springframework.data.redis.serializer.RedisSerializationContext;
import org.springframework.data.redis.serializer.StringRedisSerializer;

import java.time.Duration;

/**
 * spring cache配置
 */
@Configuration
public class SpringCacheConfig {

    @Value("${cache.enabled}")
    private Boolean cacheEnabled;

    /**
     * 随机数上界-1天时间内随机数
     */
    private static final long CACHE_RANDOM_LIMIT = 24 * 60 * 60 * 1000L;

    /**
     * 获取缓存时间
     * 缓存时间=sourceCacheTtl+random limit
     *
     * @param sourceCacheTtl sourceCacheTtl
     * @param limit          limit
     * @return long
     */
    private long cacheTtlWithRandom(long sourceCacheTtl, long limit) {
        long random = RandomUtil.randomLong(limit);
        return sourceCacheTtl + random;
    }

    /**
     * 同时随机过期时间解决缓存雪崩问题
     *
     * @return CacheManager
     */
    @Bean("testCache")
    public CacheManager cacheManager1Day(RedisConnectionFactory connectionFactory) {
        if (!cacheEnabled) {
            // 禁用缓存，不会存储
            return new NoOpCacheManager();
        }
        // 3天过期时间，转换成毫秒
        long threeDaysInMillis = 3 * 24 * 60 * 60 * 1000L;
        // 过期时间和最大空闲时间都设为3天+随机时间
        long trueTtl = cacheTtlWithRandom(threeDaysInMillis, CACHE_RANDOM_LIMIT);
        RedisCacheConfiguration config = instanceConfig(trueTtl);
        return RedisCacheManager.builder(connectionFactory)
                .cacheDefaults(config)
                .transactionAware()
                .build();
    }

    /**
     * 初始化config
     *
     * @param ttl 超时时间
     * @return RedisCacheConfiguration
     */
    private RedisCacheConfiguration instanceConfig(Long ttl) {
        // value存储为JSON格式
        // 使用Jackson2JsonRedisSerialize 替换默认序列化
        Jackson2JsonRedisSerializer<Object> jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer<>(Object.class);
        // 指定objectMapper带输入类型的序列化，如果不指定redis中则存储纯json，序列化返回后解析默认为LinkedHashMap
        // 需要自己转换类型，指定序列化类型后无需再进行转化
        ObjectMapper objectMapper = new ObjectMapper();
        objectMapper.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
        objectMapper.enableDefaultTyping(LaissezFaireSubTypeValidator.instance,
                ObjectMapper.DefaultTyping.NON_FINAL, JsonTypeInfo.As.WRAPPER_ARRAY);
        // 处理LocalDateTime
        objectMapper.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);
        objectMapper.registerModule(new JavaTimeModule());
        jackson2JsonRedisSerializer.setObjectMapper(objectMapper);
        return RedisCacheConfiguration.defaultCacheConfig()
                .entryTtl(Duration.ofSeconds(ttl))
                .serializeKeysWith(RedisSerializationContext.SerializationPair.fromSerializer(new StringRedisSerializer()))
                .serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer(jackson2JsonRedisSerializer));

    }
}

带过期时间的CacheManager使用方法如下

@Cacheable(cacheNames = "TestName",
            key = "'123456'",
            cacheManager = "testCache",
            sync = true)

其中存储到Redis中的key的规则为

• 当没有配置key时：key=cacheNames+::+SimpleKey []，如TestName::SimpleKey []
• 当配置了key时：key=cacheNames+::+key，如TestName::123456