question Re: find last element of json in nifi in Support Questions

find last element of json in nifi

smartraman — Tue, 17 Aug 2021 16:22:46 GMT

One of the JSON values needs to find the string last element. how to get the particular value in attribute with the last element.

{
"TOT_NET_AMT" : "55.00",
"H_OBJECT" : "File",
"H_GROSS_AMNT" : "55.00,58.00",
"TOT_TAX_AMT" : "9.55"
}

expected value -

{
"TOT_NET_AMT" : "55.00",
"H_OBJECT" : "File",
"H_GROSS_AMNT" : "58.00",
"TOT_TAX_AMT" : "9.55"
}

Much appreciate it in advance.

Re: find last element of json in nifi

adhishankarit — Wed, 18 Aug 2021 21:20:55 GMT

Hello ,

If your input json is coming below format

{
"TOT_NET_AMT" : "55.00",
"H_OBJECT" : "File",
"H_GROSS_AMNT" : ["55.00","58.00"],
"TOT_TAX_AMT" : "9.55"
}

If the value of H gross amount is in List of String ["55.00","58.00"] instead of String "55.00,58.00" , then you can use Jolt transformation JSON NiFi processor to define jolt spec to convert into the required output.

{
"TOT_NET_AMT" : "55.00",
"H_OBJECT" : "File",
"H_GROSS_AMNT" : "58.00",
"TOT_TAX_AMT" : "9.55"
}

Jolt transformation JSON configuration.

Jolt specification :

[
{
"operation": "modify-overwrite-beta",
"spec": {
"H_GROSS_AMNT": "=lastElement(@(1,H_GROSS_AMNT))"
}
}

]

If the input is not list of String for H Gross amount and only string with comma speparated, then please follow the below steps in order.

you will have to extract whole json into single attribute using extracttext processor and the attribute will hold entire json content , Next you can use EvaluateJsonPath which extracts each json element into each attributes , once you have all 4 attributes with value after EvaluateJsonPath , then you construct the json in Replace text processor ,H_GROSS_AMNT will still hold the string comma separated and u can use H_GROSS_AMNT:substringAfterLast(,) which extracts last element from the string value .

Examples of EvaluateJsonPath

https://nifi.apache.org/docs/nifi-docs/html/expression-language-guide.html#jsonpath

Re: find last element of json in nifi

smartraman — Thu, 19 Aug 2021 00:02:58 GMT

Thanks @adhishankarit for your help.

The value of H gross amount is in List ["55.00","58.00"] it's coming from flowfile attribute.

Will, it is possible to get the attribute value of H gross amount to use Jolt transformation JSON NiFi processor with the same as last element of H gross amount?

Thanks In advance.