question Re: How to transform a json array into a string list with nifi in Archives of Support Questions (Read Only)

How to transform a json array into a string list with nifi

adib_amine_mdr — Mon, 22 May 2017 22:22:45 GMT

Hello,

i have a queryCassandra which generate a json like this one:

{"results":[{"term":"term1"},{"term":"term2"}..]}

Now, i want to get from this all the terms values separated by some separator in string format;

ex : term1,term2,term3

So i can pass this list as a string parameter for a java main program which i've alreat set.

(i only need the transofrmation, not the java program execution) Thank you !

Re: How to transform a json array into a string list with nifi

jimmi_prajapati — Tue, 23 May 2017 03:12:18 GMT

first you need to validate JSON data , you can use this tool JSON Formatter and JSON Validator

Re: How to transform a json array into a string list with nifi

kkawamura — Sun, 18 Aug 2019 08:57:18 GMT

Hello,

I think you can do that with EvaluateJsonPath extracting String in an JSON array, followed by UpdateAttribute removes special characters such as double quotes and square brackets by Expression Language.

Here is an example NiFi template that does above conversion:

https://gist.github.com/ijokarumawak/bd37690ee8aa0bf8e9e2a47cf064e0d4

Re: How to transform a json array into a string list with nifi

adib_amine_mdr — Tue, 23 May 2017 16:45:23 GMT

thanks @kkawamura! a last question, how can i get the flowfile generated as ex : term1,term2,term3 as a parameter in the next processor?

Re: How to transform a json array into a string list with nifi

kkawamura — Tue, 23 May 2017 18:45:44 GMT

You mean how to map the attribute value (term1,term2,term3) to FlowFile content? If so, I'd use ReplaceText processor, set Replacement Value as "${attribute-name}" and Replacement Strategy as "Always Replace".

Re: How to transform a json array into a string list with nifi

Scorpy257 — Thu, 12 Jan 2023 21:03:50 GMT

In my case I have to fetch a particular key value from a json array. I was trying to do $.[key] but it just splits the array into separate json files. Is there any solution for this ? I wanted the split array as {"test1", "test2"}

Jsonarray example: [{"key":"test1", "name":"testName"}, {"key":"test2", "name":"testName2"}]