serialization of float value adds many decimal places

[charybr]

Serialization of float value using Katharsis api adds many decimal places. When we use spring controller, issue is not seen.

For example: Actual value of temperature is 2.1, but it is serialized as: {"deviceId":"dev1","time":1501237894000,"temperature":2.0999999046325684}

Expected {"deviceId":"dev1","time":1501237894000,"temperature":2.1}

katharsis-spring version: 2.6.0

[yogendra]

This is not a katharisis issue. Its jackson object mapper and float value serialization/rounding issue. You can fix it by adding your custom serializer as follows:

    @Autowired
    private ObjectMapper objectMapper;

    @PostConstruct
    public void init(){
       objectMapper.registerModule(floatModule());
    }
    @Bean
    public Module floatModule(){
        SimpleModule m = new SimpleModule("FloatModule");
        m.addSerializer(Float.class, floatSerializer());
        m.addSerializer(float.class, floatSerializer());
        return m;
    }
    @Bean
    public JsonSerializer<Float> floatSerializer(){
        return new JsonSerializer<Float>() {
            @Override
            public void serialize(Float value, JsonGenerator gen, SerializerProvider serializers) throws IOException, JsonProcessingException {
                BigDecimal d = BigDecimal.valueOf(value).setScale(2, BigDecimal.ROUND_HALF_EVEN);
                gen.writeNumber(d);
            }
        };
    }

[charybr]

Thanks Yogendra, for responding!

In the same maven project, using spring controller (that also uses jackson library) issue is not seen. Does Katharsis uses different version of jackson?

[yogendra]

Unlikely. Most likely its using a different ObjectMapper/Module setup.

[charybr]

Thanks Yogendra!