Hi Luca,
parsing JSON can be tricky if your schema is nested.
In case of a flat schema (as yours), you can read the JSON records like
this:
ExecutionEnvironment env = ...
DataSet<String> jsonRaw = env.readFileOfPrimitives(path, "},",
String.class); // "}," is a sequence that uniquely delimits your records
This will give you a raw JSON String for each record (excluding the closing
curly brace). You can implement a Map function that uses any JSON parser
(e.g., Apache Jackson) to convert this record into a Java object and a
Filter function that operates on the object.
Let me know, if you have further questions.
Cheers, Fabian
2015-07-07 11:18 GMT+02:00 Luca Ferrari <ferrari.l...@live.it>:
> Hello,
>
> I’d like to apply a filter on an attribute of a json documents. For
> example I have a Document like that
> {
> "time": "2014-08-15T21:00:00.000",
> "longitude": "136.048724",
> "latitude": "33.8144776",
> "altitude": "NULL",
> "rainfall": 0,
> "city_name": "Tokyo",
> "station_name": "NULL"
> },
> {
> "time": "2014-08-15T21:40:00.000",
> "longitude": "139.0634281",
> "latitude": "36.3894816",
> "altitude": "NULL",
> "rainfall": 6.5,
> "city_name": "Tokyo",
> "station_name": "NULL"
> },
> {
> "time": "2014-08-15T21:50:00.000",
> "longitude": "138.4768306",
> "latitude": "36.2488683",
> "altitude": "NULL",
> "rainfall": 8,
> "city_name": "Tokyo",
> "station_name": "NULL"
> }
> And I need to filter the data with rainfall > 6.
>
> How can I manage the JSON parser and the filter?
>
> Thanks
> Luca
>
