记录使用Redis缓存数据库数据

• 使用Redis缓存数据的时候，如果使用默认的RedisTemplates时，缓存的数据在取的时候经常会出现乱码的问题，就查阅网上的代码，需要自己实现RedisTemplates

/**
 * redis配置类
 */
@Configuration
public class RedisConfig {
    private static final Duration timeToLive = Duration.ZERO;

    /**
     * 自定义序列化方法的redisTemplate
     *
     * @param redisConnectionFactory Thread-safe factory of Redis connections.
     * @return redisTemplate
     */
    @Bean
    public RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory redisConnectionFactory) {
        RedisTemplate<String, Object> redisTemplate = new RedisTemplate<>();
        redisTemplate.setConnectionFactory(redisConnectionFactory);
        // 用Jackson2JsonRedisSerializer来序列化和反序列化redis的value值
        redisTemplate.setValueSerializer(serializer());

        StringRedisSerializer stringRedisSerializer = new StringRedisSerializer();
        // 使用StringRedisSerializer来序列化和反序列化redis的key值
        redisTemplate.setKeySerializer(stringRedisSerializer);

        // hash的key也采用String的序列化方式
        redisTemplate.setHashKeySerializer(stringRedisSerializer);
        // hash的value序列化方式采用jackson
        redisTemplate.setHashValueSerializer(serializer());
        redisTemplate.afterPropertiesSet();
        return redisTemplate;
    }

    @Bean
    public CacheManager cacheManager(RedisConnectionFactory factory) {
        RedisSerializer<String> redisSerializer = new StringRedisSerializer();
        // 配置序列化（解决乱码的问题）
        RedisCacheConfiguration config = RedisCacheConfiguration.defaultCacheConfig()
                // 缓存有效期
                .entryTtl(timeToLive)
                // 使用StringRedisSerializer来序列化和反序列化redis的key值
                .serializeKeysWith(RedisSerializationContext.SerializationPair.fromSerializer(redisSerializer))
                // 使用Jackson2JsonRedisSerializer来序列化和反序列化redis的value值
                .serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer(serializer()))
                // 禁用空值
                .disableCachingNullValues();

        return RedisCacheManager.builder(factory)
                .cacheDefaults(config)
                .build();
    }

    /**
     * 生成 Jackson2JsonRedisSerializer，用于序列化和反序列化redis的value值
     *
     * @return Jackson2JsonRedisSerializer
     */
    private Jackson2JsonRedisSerializer<Object> serializer() {
        // 使用Jackson2JsonRedisSerializer来序列化和反序列化redis的value值
        Jackson2JsonRedisSerializer<Object> jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer<>(Object.class);
        ObjectMapper objectMapper = new ObjectMapper();

        // 指定要序列化的域，field,get和set,以及修饰符范围，ANY是都有包括private和public
        objectMapper.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);

        // 指定序列化输入的类型，类必须是非final修饰的，final修饰的类，比如String,Integer等会跑出异常
        objectMapper.activateDefaultTyping(LaissezFaireSubTypeValidator.instance, ObjectMapper.DefaultTyping.NON_FINAL);

        jackson2JsonRedisSerializer.setObjectMapper(objectMapper);
        return jackson2JsonRedisSerializer;
    }
}