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From kant kodali <kanth...@gmail.com>
Subject Re: How to convert Row to JSON in Java?
Date Mon, 11 Sep 2017 20:15:48 GMT
getValuesMap is not very Java friendly. I have to do something like this

String[] fieldNames = row.schema().fieldNames();
Seq<String> fieldNamesSeq =
JavaConverters.asScalaIteratorConverter(Arrays.asList(fieldNames).iterator()).asScala().toSeq();
String json = row.getValuesMap(fieldNamesSeq).toString();


On Mon, Sep 11, 2017 at 12:39 AM, Riccardo Ferrari <ferrarir@gmail.com>
wrote:

> Hi Ayan, yup that works very well however I believe Kant's other mail
> "Queries with streaming sources must be executed with writeStream.start()"
> is adding more context.
> I think he is trying leverage on structured streaming and applying the rdd
> conversion to a streaming dataset is breaking the streaming lineage.
> Best,
>
> On Mon, Sep 11, 2017 at 3:51 AM, ayan guha <guha.ayan@gmail.com> wrote:
>
>> Sorry for side-line question, but for Python, isn't following the easiest:
>>
>> >>> import json
>> >>>* df1 = df.rdd.map(lambda r: json.dumps(r.asDict()))*
>> >>> df1.take(10)
>> ['{"id": 1}', '{"id": 2}', '{"id": 3}', '{"id": 4}', '{"id": 5}']
>>
>>
>>
>>
>> On Mon, Sep 11, 2017 at 4:22 AM, Riccardo Ferrari <ferrarir@gmail.com>
>> wrote:
>>
>>> Hi Kant,
>>>
>>> You can check the getValuesMap
>>> <https://spark.apache.org/docs/2.2.0/api/java/org/apache/spark/sql/Row.html#getValuesMap-scala.collection.Seq->.
>>> I found this post <https://stackoverflow.com/a/41602178/8356352>
>>> useful, it is in Scala but should be a good starting point.
>>> An alternative approach is combine the 'struct' and 'to_json' functions
>>> <https://spark.apache.org/docs/2.2.0/api/java/org/apache/spark/sql/functions.html>.
>>> I have not tested this in Java but I am using it in Python.
>>>
>>> Best,
>>>
>>> On Sun, Sep 10, 2017 at 1:45 AM, kant kodali <kanth909@gmail.com> wrote:
>>>
>>>> toJSON on Row object.
>>>>
>>>> On Sat, Sep 9, 2017 at 4:18 PM, Felix Cheung <felixcheung_m@hotmail.com
>>>> > wrote:
>>>>
>>>>> toJSON on Dataset/DataFrame?
>>>>>
>>>>> ------------------------------
>>>>> *From:* kant kodali <kanth909@gmail.com>
>>>>> *Sent:* Saturday, September 9, 2017 4:15:49 PM
>>>>> *To:* user @spark
>>>>> *Subject:* How to convert Row to JSON in Java?
>>>>>
>>>>> Hi All,
>>>>>
>>>>> How to convert Row to JSON in Java? It would be nice to have .toJson()
>>>>> method in the Row class.
>>>>>
>>>>> Thanks,
>>>>> kant
>>>>>
>>>>
>>>>
>>>
>>
>>
>> --
>> Best Regards,
>> Ayan Guha
>>
>
>

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