SpringBoot的cache缓存，是针对返回值的一种操作
springboot使用redis做缓存时，默认只需要导入redis依赖，即可实现使用redis做缓存

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

不需要导入cache依赖
在启动类上加上@EnableCaching 即可开启缓存功能
关于各个注解的使用，这里不再细说，网上详细的教程很多，这里主要讲一下如何指定过期时间

默认是永不过期，如果需要指定过期时间，则需要增加配置类

@Configuration
public class MyRedisCacheManager {


    /**
     * redis模板配置以及序列化配置
     *
     * @param factory 工厂
     * @return {@link RedisTemplate}<{@link String}, {@link Object}>
     */
    @Bean
    public RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory factory) {
        RedisTemplate<String, Object> template = new RedisTemplate<>();
        template.setConnectionFactory(factory);
        Jackson2JsonRedisSerializer jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer(Object.class);
        ObjectMapper om = new ObjectMapper();
        om.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
        om.activateDefaultTyping(LaissezFaireSubTypeValidator.instance, ObjectMapper.DefaultTyping.NON_FINAL);
        jackson2JsonRedisSerializer.setObjectMapper(om);
        StringRedisSerializer stringRedisSerializer = new StringRedisSerializer();

        //key 采用的String 的序列化方式
        template.setKeySerializer(stringRedisSerializer);
        //hashde key 也采用String的序列化方式
        template.setHashKeySerializer(stringRedisSerializer);
        //value 序列化方式采用jackson
        template.setValueSerializer(jackson2JsonRedisSerializer);
        //hash 的 value序列化方式采用jackson
        template.setHashKeySerializer(jackson2JsonRedisSerializer);
        template.afterPropertiesSet();
        template.afterPropertiesSet();
        return template;
    }


    @Bean
    RedisCacheWriter writer(RedisTemplate<String, Object> redisTemplate) {
        return RedisCacheWriter.nonLockingRedisCacheWriter(Objects.requireNonNull(redisTemplate.getConnectionFactory()));
    }

    @Bean
    CacheManager cacheManager(RedisCacheWriter writer) {
        RedisSerializer<String> redisSerializer = new StringRedisSerializer();
        Jackson2JsonRedisSerializer jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer(Object.class);

        Map<String, RedisCacheConfiguration> configurationMap = new HashMap<>();

        // 配置序列化（解决乱码的问题）
        RedisCacheConfiguration config = RedisCacheConfiguration.defaultCacheConfig()
                .entryTtl(Duration.ofHours(1))//time
                .serializeKeysWith(RedisSerializationContext.SerializationPair.fromSerializer(redisSerializer))
                .serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer(jackson2JsonRedisSerializer))
                .disableCachingNullValues();

        //配置list缓存的过期时间为100S
        configurationMap.put("list", config.entryTtl(Duration.ofSeconds(100)));

        //解决查询缓存转换异常的问题
        ObjectMapper om = new ObjectMapper();
        om.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
        om.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL);
        jackson2JsonRedisSerializer.setObjectMapper(om);

        return RedisCacheManager.builder(writer)
                .initialCacheNames(configurationMap.keySet())
                .withInitialCacheConfigurations(configurationMap)
                //其他缓存过期时间为500S
                .cacheDefaults(config.entryTtl(Duration.ofSeconds(500)))
                .build();
    }
}