Extract all particular field from JSON in mule esb - json

Question

I have this json payload, I would want to collect all externalListingId in one shot -
{
"listings": {
"numFound": 3,
"listing": [
{
"status": "INACTIVE",
"pricePerTicket": {
"amount": 100,
"currency": "USD",
},
"paymentType": "1",
"externalListingId": "12208278",
"city": "New York"
},
{ "status": "ACTIVE",
"pricePerTicket": {
"amount": 4444,
"currency": "USD"
},
"paymentType": "1",
"externalListingId": "CID1421798897102:151681733",
"city": "Seattle"
}
]
}
}
I am using MVEL expression -
<enricher target="#[flowVars['sData']]" source="#[(externalListingId in payload.listing)]" doc:name="Message Enricher">
<json:json-to-object-transformer returnClass="java.util.HashMap" doc:name="JSON to Object"/>
</enricher>
But this is giving error !! - Message payload is of type: ReleasingInputStream.
Scenario - I would like to collect all externalListingId into flowVariable, convert to hashmap. I have another CSV file as input, would like to loop through that payload and check if this map contains the id!!
I am following this earlier post -
Extracting array from JSON in mule esb

Answer 1

You need to transform the message's streaming payload to an object with:
<json:json-to-object-transformer returnClass="java.lang.Object" />
before the enricher, and remove the one you have inside of it.
You also need to fix your MEL, as the listings property is missing in it:
source="#[(externalListingId in payload.listings.listing)]"
Source: http://www.mulesoft.org/documentation/display/current/Mule+Expression+Language+Tips#MuleExpressionLanguageTips-JSONProcessing

Answer 2

it worked with the same definition.
<flow name="test-mule-json-extractFlow">
<http:listener config-ref="HTTP_Listener_Configuration" path="/json" doc:name="HTTP"/>
<enricher source="#[(externalListingId in payload.listings.listing)]" target="#[flowVars.ids]" doc:name="Message Enricher">
<json:json-to-object-transformer returnClass="java.util.HashMap" doc:name="JSON to Object"/>
</enricher>
<logger message=":::::::::::::::#[flowVars.ids]" level="INFO" doc:name="Logger"/>
</flow>
Note: the json input you mentioned is not valid due to available of an extra comma.