Groovy & json: How to get the length of an array from json?

Question

I am using curl to get some data, then parsing it with JsonSlurper. The data structure is

"results" : [ 
   {
      "uri" : "http://localhost:8081/artifactory/api/storage/...",
      "created" : "2015-11-27"
   },
   {
      "uri" : "http://localhost:8081/artifactory/api/storage/...",
      "created" : "2015-11-27"
   }, 
   {
      "uri" : "http://localhost:8081/artifactory/api/storage/...",
      "created" : "2015-11-30"
   } 
]

So if I'm not mistaken, the entire thing is considered an object. But there is an array in the object (results) which contains objects in that array.

I need to get the length of the results array. When I try to do json.result.length, I receive a null.

How can I get the length of the results array?

def list = ['curl', '-u', 'user:pass',     "http://localhost:8081/..."].execute()
def json = new JsonSlurper().parseText(list.text)
println json.result.size()

looks like its not parsing as JSON, result coming as string. Can you print the result class name: println json.class. for JSON result it should print as map. — sfgroups, Dec 01 '15 at 12:36

Rao · Accepted Answer · 2015-12-01T02:35:55.610

11

What I see is, you are using incorrect property to get the size. Need to use results instead of result. Thats is the reason you are seeing that error as result is null(because there is no such property)

Here is working script and gets output as 3:

import net.sf.json.groovy.JsonSlurper
def jsonText='''{
"results" : [
   {
      "uri" : "http://localhost:8081/artifactory/api/storage/...",
      "created" : "2015-11-27"
   },
   {
      "uri" : "http://localhost:8081/artifactory/api/storage/...",
      "created" : "2015-11-27"
   },
   {
      "uri" : "http://localhost:8081/artifactory/api/storage/...",
      "created" : "2015-11-30"
   }
]
}'''
def json = new JsonSlurper().parseText(jsonText) 
println json.results.size()
assert 3 == json.results.size(), "Array size is not matching"

edited Dec 01 '15 at 02:35

answered Dec 01 '15 at 02:28

Rao

20,781
11
57
77

Thanks so much! First off, I can't believe I had a typo - but it wouldn't have solved my problem because I was trying to use .length. So does .length not work because it's considered a collection and not an array and that's why I need to use .size? Also, is the last line "assert 3 ==..." just error checking? Thanks a ton again, it works perfectly (just trying to understand everything!) – crystallinity Dec 01 '15 at 14:53
It happens at times. Right, size is for collection. Nice thread - size vs lengh - http://stackoverflow.com/questions/300522/count-vs-length-vs-size-in-a-collection. Yes, just checking if results size matching 3. – Rao Dec 01 '15 at 16:11
I can't thank you enough for your help. This issue was preventing me from going further with the rest of my code. Thank you thank you thank you! =) – crystallinity Dec 01 '15 at 16:15

Opal · Answer 2 · 2015-12-01T08:05:53.567

2

It will be:

def response = ... // your response as text, stream..
def parsed = new JsonSluper().parse(response) // parseText if string
println parsed.results.size()

BTW: size() is for Collection, length for String, note method vs field. In groovy you can use size() for String as well.

edited Dec 01 '15 at 08:05

answered Nov 30 '15 at 22:09

Opal

81,889
28
189
210

Hey, still getting "cannot invoke method size() on null object". Sec.. fixing code output to look better. – crystallinity Nov 30 '15 at 22:14
@crystallinity, could you please provide the whole JSON String? – Opal Nov 30 '15 at 22:15
hey, sure. I'll edit my main post in just 2 minutes. – crystallinity Nov 30 '15 at 22:16
Okay, edited - let me know if you need anything else! Thanks. – crystallinity Nov 30 '15 at 22:18
@crystallinity yes, I need. What are you getting under `list`. Paste it. – Opal Nov 30 '15 at 22:19
I'm not sure I understand what you're asking - I'm kind of new to this stuff. But, the first block of code in my main post is what is returned from the list curl. Is that what you mean? That is the complete JSON string that is returned. – crystallinity Nov 30 '15 at 22:20
@crystallinity, that's what I mean. Add `println(list)` and paste the result ;) – Opal Nov 30 '15 at 22:21
`:listArtifactoryApi java.lang.UNIXProcess@1c4ea79b` Gotcha, does this help? – crystallinity Nov 30 '15 at 22:23
Please ignore the big block of code I added before, I had an extra println of the result. But, this is all I get if i do a "println list" - `java.lang.UNIXProcess@5ffc255d` – crystallinity Nov 30 '15 at 22:25
Ok, as as you see, there's no `results` field here. You've something misconfigured. – Opal Nov 30 '15 at 22:26
Ok, what does `list.text` returns then. – Opal Nov 30 '15 at 22:26
But what's strange is if I do a println json.results.[0].uri it brings up the first index of the data in my first post! – crystallinity Nov 30 '15 at 22:27
"Execution failed, Stream closed" for list.text (build failed) – crystallinity Nov 30 '15 at 22:27
So now you see why you don't get any result. – Opal Nov 30 '15 at 22:28
So if the stream doesn't close then I can get a result? How do I do this? – crystallinity Nov 30 '15 at 22:29
I need to drive home now, I'll check this when I'm there. Thanks again for your efforts. – crystallinity Nov 30 '15 at 22:43
@crystallinity, not exactly. There's rather a problem with executing curl command itself. It's hard to reproduce. Apply step-by-step approach. – Opal Nov 30 '15 at 22:45

score 0 · Answer 3 · answered Jan 18 '19 at 12:20

{
"projects":
  [
  {
    "platform": "java",
    "name":"abc"

  },
  {
    "platform": ".net",
    "name":"abcd"

}]
}

for this json file list.json how to get json size or number of applications count. below code worked for me in groovy as i was using in it my jenkinsfile.

import groovy.json.JsonBuilder
import groovy.json.JsonOutput
import groovy.io.FileType
def applicationCount()
{
  jsonFile1 = 'list.json'
  def json1 = readJSON file: jsonFile1
  totalApplication = json1.projects.size()
  println "count" + totalApplication
  println "applicationname" + json1['projects'][0]['name']
}

Its actual code that i used in my automation.So yes its copy from my local and pasted in this window.Let me know if you have any question. — JYOTI SINGH, Feb 14 '19 at 19:00

Groovy & json: How to get the length of an array from json?

3 Answers3