Retrieve a list of strings from JSON in java

Question

we are having trouble with getting a message out of a JSON message. We are rather confused by how the response is formatted since the key we receive for the list is empty but that isn't anything we can change. This is a response from a backend API that sends error messages when something goes wrong.

This is the JSON string. What we want to extract to a simple string is "Passwords must be at least 6 characters."

{
  "message": "The request is invalid.",
  "modelState": {
    "": [
      "Passwords must be at least 6 characters."
    ]
  }
}

What we have tried are a few things found over here and here but without any success.

Right now we are completely lost on how to get that one string out of that JSON message so literally any help is appreciated.

Regards, CptSeasick

It's good form to show what you've tried. For example, if the key weren't empty, would you know how to do it? What happens when you try this but with an empty string instead? — dcsohl, Oct 20 '15 at 17:48

score 1 · Answer 1 · answered Oct 20 '15 at 17:36

1

You can access it via

object.modelstate[""]

answered Oct 20 '15 at 17:36

LeFex

258
1
10

Oğuzhan Döngül · Answer 2 · 2015-10-20T20:58:50.140

Your modelState object's String is named as "". I mean empty string.

If you can change the name of it like below:

{
  "message": "The request is invalid.",
  "modelState": {
    "errorMessage": [
      "Passwords must be at least 6 characters."
    ]
  }
}

and access your object like that:

myJSONobject.getJSONObject("modelState").getJSONArray("errorMessage").getString(0);

or just try :

myJSONobject.getJSONObject("modelState").getJSONArray("").getString(0);

score 0 · Accepted Answer · answered Oct 20 '15 at 17:57

You can do something like this:

package com.stackoverflow.answer;

import org.json.JSONObject;

public class JsonTest {

    public static void main(String[] args) {
        String response = "{ \"message\": \"The request is invalid.\", \"modelState\": { \"\": [ \"Passwords must be at least 6 characters.\"]}}";
        JSONObject jsonObject = new JSONObject(response);
        String errorMessage = jsonObject.getJSONObject("modelState").getJSONArray("").getString(0);
        System.out.println(errorMessage);
    }

}

Thank you, this is exactly what we were searching for! We tried similar things before but this resolves our issue. — CptSeasick, Oct 20 '15 at 18:49

Retrieve a list of strings from JSON in java

3 Answers3