Redis caching Map<Integer, String>

Question

I an using redis cache and faced the problem: map with integer key is serialized as String like this:

 "1":"AAAA","2":"BBB","3":"CCC"

This is how my config looks like:

@Bean
    public RedisCacheConfiguration myCacheConfiguration()
    {
        return RedisCacheConfiguration.defaultCacheConfig()
                .entryTtl(Duration.ZERO)
                .disableCachingNullValues()
                .serializeValuesWith(RedisSerializationContext.SerializationPair
                        .fromSerializer(new Jackson2JsonRedisSerializer<>(Map.class)));
    }

  @Bean
    public CacheManager myCacheManager(RedisConnectionFactory redisConnectionFactory)
    {
        return RedisCacheManager.builder(redisConnectionFactory)
                .cacheDefaults(myCacheConfiguration())
                .transactionAware()
                .build();
    }

I tried to pass GenericJackson2JsonRedisSerializer to serializeValuesWith(), but is doesn't work. Is there any way to serialize\deserialize Integer keys of map as number?

Answer 1

The issue is easily solved by adding overriding of method JavaType getJavaType(Class clazz) in Jackson2JsonRedisSerializer. Documentation says:

/**
     * Returns the Jackson {@link JavaType} for the specific class.
     * <p>
     * Default implementation returns {@link TypeFactory#constructType(java.lang.reflect.Type)}, but this can be
     * overridden in subclasses, to allow for custom generic collection handling. For instance:
     *
     * <pre class="code">
     * protected JavaType getJavaType(Class&lt;?&gt; clazz) {
     *  if (List.class.isAssignableFrom(clazz)) {
     *      return TypeFactory.defaultInstance().constructCollectionType(ArrayList.class, MyBean.class);
     *  } else {
     *      return super.getJavaType(clazz);
     *  }
     * }
     * </pre>
     *
     * @param clazz the class to return the java type for
     * @return the java type
     */
    protected JavaType getJavaType(Class<?> clazz) {
        return TypeFactory.defaultInstance().constructType(clazz);
    }

So, I just overriding this method like this:

public class CustomSerializer extends Jackson2JsonRedisSerializer
{
    public JurisdictionsSerializer(Class type)
    {
        super(type);
    }


    @Override
    protected JavaType getJavaType(Class clazz)
    {
        return TypeFactory.defaultInstance()
                .constructMapType(Map.class, Integer.class, String.class);
    }
}

And then add this serializer to redis configuration like this:

@Bean
    public RedisCacheConfiguration myCacheConfiguration()
    {
        return RedisCacheConfiguration.defaultCacheConfig()
                .entryTtl(Duration.ZERO)
                .disableCachingNullValues()
                .serializeValuesWith(RedisSerializationContext.SerializationPair
                        .fromSerializer(new CustomSerializer(Map.class)));
    }