How to properly parse JSON in Groovy - json

Question

I am not sure how to properly parse through nested JSON using Groovy. I have included a working Python script so you can see exactly what I'm trying to do in Groovy.
JSON I need to parse:
json_payload = {"number": 3585, "url": "https://jenkins.test.com/job/test/3585/",
"displayName": "test_3585", "timestamp": 1516992464686,
"actions": [{"causes": [{"userId": "test"}]}]}
What I want to do (Python):
class JenkinsParser:
def __init__(self, json_data):
self.display_name = json_data['displayName']
self.url = json_data['url']
self.start_time = json_data['timestamp']
self.exec_url = json_data['url']
self.exec_number = json_data['number']
self.user = None
actions = json_data['actions']
for a in actions:
if 'causes' in a:
for cause in a['causes']:
if 'userId' in cause:
self.user = cause['userId']
url_split = self.execution_url.split("/job/")
self.jenkins_url = url_split[0]
self.job_name = url_split[-1].split("/")[0]
Note: The Groovy does not necessarily need to be a class, and doesn't need to use JSonSlurper
If I use JsonSlurper
def slurper = new groovy.json.JsonSlurper()
def result = slurper.parseText(json_payload)
Can I access all the values I need like so?
result.displayName
result.url
result.timestamp
result.url
result.number
result.actions.causes.userId
I'm not sure how to grab userId..

Answer 1

Yes, you can access the values like you described.
You could access userId like result​.actions.first().causes.first().userId​ if you're sure your data is structured exactly like that. If you may or may not have actions, or may or may not have causes, you could do something like result​.actions?.first()?.causes?.first()?.userId​ to make your access null-safe, or you could use the spread (*.) operator to access userId if there may be multiple actions or causes.
Per your comment about something returning null, this works as expected:
def json_payload = """{"number": 3585, "url": "https://jenkins.test.com/job/test/3585/", "displayName": "test_3585", "timestamp": 1516992464686, "actions": [{"causes": [{"userId": "test"}]}]}"""
def slurper = new groovy.json.JsonSlurper()
def result = slurper.parseText(json_payload)
return result​.actions?.first()?.causes?.first()?.userId​
and returns "test". If you are not seeing similar results you may have a syntax error or different key in your actual data.