API JSON response: get key value

Below is the response message (JSON) from an API endpoint. I need to parse the JSON response, and I need to retrieve the RequestID key.

{
  "Status":1,
  "RequestID":"29d2d52c-e8fe-447f-9ee1-15e4624be58f",
  "Data":[
    {
      "RegNumber":"ASD3948506",
      "CaseData":{
        "CaseResult":{
          "Message":"success",
          "RequestID":"8C15473C0F7771F410928D5D91362B80"
        },
        "ErrorMessageList":[
        ]
      }
    }]
}

Below is my code to retrieve the RequestID[Inside the CaseResult]

JSONObject actualJson = new JSONObject(response.getResponseText())
def requestID = actualJson.get('Data[0].CaseData.CaseResult.RequestID')

When I executed it, I got the below error message.

org.json.JSONException: JSONObject["Data[0].CaseData.CaseResult.RequestID"] not found.

Could any one provide a solution for this?

Solution

You cannot query values using that kind of string:

'Data[0].CaseData.CaseResult.RequestID'

You will get null as result

Explicit access to the values

Using JsonSlurper you can parse any valid string json to a groovy object.

def jsonSlurper = new JsonSlurper();
def object = jsonSlurper.parse("{....}")
println object
println object.Status
println object["Status"]
println object["Data"][0]["CaseResult"]["RequestId"]

Jsonpath

This is the only library capable to use string queries to get values from the json:

$.Data[0].CaseData.CaseResult.RequestID

String json = "...";
String jsonPathExpression = "$.Data[0].CaseData.CaseResult.RequestID"; 
JsonNode jsonNode = JsonPath.parse(json).read(jsonPathExpression, JsonNode.class);

API JSON response: get key value

Explicit access to the values

Jsonpath

References