`MappingRedisConverter` does not support generic properties

[renjiancheng]

Sorry, the problem on StackOverflow didn't answer, so I moved it over here, in spring-data-redis, I added a piece of data with generics using stream and Jackson2HashMapper, but when a consumer consumes it, it can only read the entity's type. All other attributes are lost. How can I consume it correctly?
producer code:

    @Bean
    RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory rf) {
        RedisTemplate<String, Object> rt = new RedisTemplate<>();
        rt.setConnectionFactory(rf);
        rt.setKeySerializer(RedisSerializer.string());
        rt.setValueSerializer(RedisSerializer.json());
        rt.setHashKeySerializer(RedisSerializer.string());
        rt.setHashValueSerializer(RedisSerializer.json());
        return rt;
    }

    @Bean
    ApplicationRunner runner(RedisTemplate<String, Object> rt) {
        return arg -> {
            MyMessage<User> userMyMessage = new MyMessage<User>().setReceiver(1)
                                                                 .setClientType("app")
                                                                 .setPayload(new User().setName("testName")
                                                                                       .setAge(10)
                                                                                       .setId(1));
            Jackson2HashMapper hashMapper = new Jackson2HashMapper(false);
            rt.opsForStream()
              .add(StreamRecords.newRecord()
                                .in("my-stream")
                                .ofMap(hashMapper.toHash(userMyMessage)));
        };
    }

sequence in Redis:

consumer code:

 @Bean
    public RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory rcf) {
        RedisTemplate<String, Object> rt = new RedisTemplate<>();
        rt.setConnectionFactory(rcf);
        rt.setKeySerializer(RedisSerializer.string());
        rt.setValueSerializer(RedisSerializer.json());
        rt.setHashKeySerializer(RedisSerializer.string());
        rt.setHashValueSerializer(RedisSerializer.json());
        return rt;
    }

    @Bean
    StreamMessageListenerContainer.StreamMessageListenerContainerOptions<String, ObjectRecord<String, Object>> hashContainerOptions() {
        return StreamMessageListenerContainer.StreamMessageListenerContainerOptions.builder()
                                                                                   .pollTimeout(Duration.ofSeconds(1))
                                                                                   .objectMapper(new Jackson2HashMapper(false))
                                                                                   .build();
    }

    @Bean
    StreamMessageListenerContainer<String, ObjectRecord<String, Object>> hashContainer(
            StreamMessageListenerContainer.StreamMessageListenerContainerOptions<String, ObjectRecord<String, Object>> options,
            RedisConnectionFactory redisConnectionFactory,
            RedisTemplate<String, Object> redisTemplate) {

        var container = StreamMessageListenerContainer.create(redisConnectionFactory, options);
        container.start();
        String group = "default-group";
        String key = "my-stream";
        try {
            redisTemplate.opsForStream().createGroup(key, group);
        } catch (Exception ignore) {
        }
        container.receiveAutoAck(
                Consumer.from(group, "default-consumer"),
                StreamOffset.create(key, ReadOffset.lastConsumed()),
                message -> {
                    log.info("receive message stream:{}, id:{} value:{}", message.getStream(), message.getId(), message.getValue());
                }
        );
        return container;
    }

consumer log:

receive message stream:my-stream, id:1655890663894-0 value:"com.commons.MyMessage"

thanks

[mp911de]

Objects in a stream are serialized to a hash and can use plain String serialization, JSON isn't required as we already have a hash structure. The problem though is that MappingRedisConverter does not support generic properties and therefore any generic property values aren't serialized/deserialized properly.

We need to fix that.

One more thing: The StreamMessageListenerContainer must know the returned target type in advance to identify which StreamObjectMapper to use. Since object types can hold simple (e.g. numbers) or complex types (entities), please configure the target type via StreamMessageListenerContainerOptions.builder().targetType(…).