How to extract json array using EvaluateJsonPath processor in NiFi?

murali2425 — Mon, 01 Mar 2021 03:16:01 GMT

Hi,

I have json flowfile, [{"prediction":"Test2"},{"prediction":"Test2"}].

I am want extract the 1st part of the array ie prediction":"Test2 my destination is flowfile-attribute using EvaluateJsonPath .

I have added a custom attribute mlresult --->$.prediction[0], to extract the "Test2" into mlresult, but I am getting empty string for the mlresults for the flow file attribute section.

flow file : [{"prediction":"Test2"},{"prediction":"Test2"}]

EvaluateJsonPath configuration:

How to get the value(only one) Test2 to mlresult?

Thanks

--Murali

Re: How to extract json array using EvaluateJsonPath processor in NiFi?

justenji — Mon, 01 Mar 2021 06:23:41 GMT

@murali2425

Here are two possible solutions.

At solution 1 the value is set into an array.

At solution 2 I took the flowfile-content (json) and set it into an attribute. Then you can work with expression language to get the value.

For testing the syntax I recommend this site:
http://jsonpath.herokuapp.com/

question How to extract json array using EvaluateJsonPath processor in NiFi? in Support Questions

How to extract json array using EvaluateJsonPath processor in NiFi?

Re: How to extract json array using EvaluateJsonPath processor in NiFi?