Problem

• I receive JSON data from Django REST Server
• However, it caused ‘Unrecognized token’ error
• In my case, this error occured by ‘True’ and ‘None’

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2019-09-06 17:20:57.019 28853-28945/*** E/dorbae: Failed to get DB data. com.fasterxml.jackson.core.JsonParseException: Unrecognized token 'True': was expecting ('true', 'false' or 'null') at [Source: (byte[])"{'name': 'WFS', 'columns': ['time', 'current'], 'values': [['2019-08-24T15:20:31+09:00', 7], ['2019-08-24T11:28:41+09:00', 6], ['2019-08-24T06:29:02+09:00', 4], ['2019-08-24T05:50:00+09:00', 4], ['2019-08-24T02:15:17+09:00', 2], ['2019-08-24T02:15:12+09:00', 2], ['2019-08-23T18:05:16+09:00', 2], ['2019-08-23T17:24:44+09:00', 4], ['2019-08-23T17:22:04+09:00', 2], ['2019-08-23T17:21:59+09:00', 2], ['2019-08-23T06:36:24+09:00', 4], ['2019-08-23T03:45:43+09:00', 2], ['2019-08-23T03:45:38+09:00', 2],"[truncated 1953313 bytes]; line: 1, column: 1953814] at com.fasterxml.jackson.core.JsonParser._constructError(JsonParser.java:1804) at com.fasterxml.jackson.core.base.ParserMinimalBase._reportError(ParserMinimalBase.java:703) at com.fasterxml.jackson.core.json.UTF8StreamJsonParser._reportInvalidToken(UTF8StreamJsonParser.java:3532) at com.fasterxml.jackson.core.json.UTF8StreamJsonParser._handleUnexpectedValue(UTF8StreamJsonParser.java:2627) at com.fasterxml.jackson.core.json.UTF8StreamJsonParser.nextFieldName(UTF8StreamJsonParser.java:1053) at com.fasterxml.jackson.databind.deser.BeanDeserializer.vanillaDeserialize(BeanDeserializer.java:295) at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:151) at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:4013) at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3091) at ...

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2019-09-06 17:30:03.244 29666-29758/*** E/dorbae: com.fasterxml.jackson.databind.JsonMappingException: Unrecognized token 'None': was expecting 'null', 'true', 'false' or NaN at [Source: (byte[])"{'name': 'qbsiotseries', 'columns': ['time', 'TEMPERATURE', 'HUMIDITY', 'CO2PPM', 'ILLUMINANCE', 'VALUE00', 'VALUE01', 'VALUE02', 'VALUE03'], 'values': [['2019-08-23T08:00:00Z', None, None, None, None, None, None, None, None], ['2019-08-23T09:00:00Z', None, None, None, None, None, None, None, None], ['2019-08-23T10:00:00Z', None, None, None, None, None, None, None, None], ['2019-08-23T11:00:00Z', None, None, None, None, None, None, None, None], ['2019-08-23T12:00:00Z', None, None, None, None, No"[truncated 25509 bytes]; line: 1, column: 179] (through reference chain: ***.InfluxDBResultSet["values"]->java.lang.Object[][0]) at com.fasterxml.jackson.databind.deser.std.ObjectArrayDeserializer.deserialize(ObjectArrayDeserializer.java:206) at com.fasterxml.jackson.databind.deser.std.ObjectArrayDeserializer.deserialize(ObjectArrayDeserializer.java:21) at com.fasterxml.jackson.databind.deser.impl.MethodProperty.deserializeAndSet(MethodProperty.java:127) at com.fasterxml.jackson.databind.deser.BeanDeserializer.vanillaDeserialize(BeanDeserializer.java:288) at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:151) at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:4013) at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3091) at ...

Cause

• My architecture

• Jaskcon libarary was not able to recognize the tokens such as ‘True’, ‘None’ and my django server didn’t nomalize json data

Solution

1. Nomalize JSON data in Django server

• json.dumps method nomalizes JSON data followed by ECMA-404
• True -> true & None -> null
• Add this code

import json

...

json.dumps(jsonObject)

...

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client = InfluxDBClient(host, port, user, password, db_name) result = client.query(query) _value = '' _series = result.raw.get('series') if _series is not None: # None -> Null & Object -> Object[] _value = json.dumps(_series) return HttpResponse(_value, status=200) # return HTTP Response return HttpResponse(_value, status=404)

2. Skip null data in Android

• Add this code

...

ObjectMapper mapper = new ObjectMapper();

...

mapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);

...

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ObjectMapper mapper = new ObjectMapper(); mapper.configure(JsonParser.Feature.ALLOW_SINGLE_QUOTES, true); // 싱글 쿼테이션 허용 mapper.setSerializationInclusion(JsonInclude.Include.NON_NULL); InfluxDBResultSet[] influxDBResultSetArray = mapper.readValue(data, InfluxDBResultSet[].class);

---

References

• JSON encoder and decoder
• Standard ECMA-404