https://docs.spring.io/spring-data/redis/reference/redis/hash-mappers.html ```java @Autowired HashOperations<String, byte[], byte[]> hashOperations; ``` this won't work. There are some discussion about it. * https://github.com/spring-projects/spring-data-redis/issues/586 * https://stackoverflow.com/questions/44709092/redis-hashoperations-dependency-not-found it turns out this works. ```java @Resource(name = "redisTemplate") HashOperations<String, byte[], byte[]> hashOperations; ``` In the mean time, `@Autowired @Qualifier("redisTemplate")` fails. I don't konw why.