Java Extracting Data from JSON Not Working

Question

I was having some problem when trying to extract information out from JSON. Here is the example of my JSON:

// removed

My responseMessage is just a string. And my code to extract the info out:

// removed

I tried to follow the solution from this thread However, nothing has been printed out and there is no error message. Any ideas on how to resolve this? Thanks!

EDIT

I realized the problem is due to this error: java.lang.ClassCastException: org.json.simple.JSONObject cannot be cast to org.json.JSONObject

However, if I changed my import for JSONObject to import org.json.simple.JSONObject; the code above will break. Any ideas?

What exactly is the error? Also, your json doesn't seem to be valid, you need to put response in curly braces. — Sukhpal Singh
– Sukhpal Singh, Commented Dec 19, 2018 at 2:06
Your root doesn't have schedules array but it's nested under response. Apart from this there doesn't seem to be any obvious error. Separate note, paste json instead of image. — Sukhpal Singh
– Sukhpal Singh, Commented Dec 19, 2018 at 2:29
I'm able to print username with similar code. Though I used gson. Debugging is the only solution. — Sukhpal Singh
– Sukhpal Singh, Commented Dec 19, 2018 at 2:46

Sukhpal Singh · Accepted Answer · 2018-12-19 03:38:52Z

1

As asked in comments, below code is working using gson

JsonParser parser = new JsonParser();
JsonObject root =  (JsonObject) parser.parse(json);
JsonArray schedulesArray = root.getAsJsonObject("response").getAsJsonArray("schedules");
JsonObject firstSchedule = (JsonObject) schedulesArray.get(0);
String userName = firstSchedule.get("username").getAsString();

answered Dec 19, 2018 at 3:38

Sukhpal Singh

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Comments

TongChen · Accepted Answer · 2018-12-19 02:26:03Z

-1

I have a “stupid” method.First,you should create three DTOs,it's may like this:

public class Schedule {
    private String username;
    private String scheduleId;
    private String SCHEDULEsTARTtIME;
    private String NOTES;
    private String familyName;
    private String principalId;
    private String friendlyName;
    private String scheduleEndTime;

    // get set methods
}

public class ResponseInfo {
    private String instrumentName;
    private String instrumentId;
    private String instrumentType;
    private List<Schedule> schedules;
}

public class Response {
    private ResponseInfo response;
}

then,convert response string to Response DTO

Response newResponse = mapper.readValue(content,Response.class);

answered Dec 19, 2018 at 2:26

TongChen

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2 Comments

QWERTY Over a year ago

Why not just use the JSONParser to parse the string responseMessage to JSON instead?

TongChen Over a year ago

Just used to it，you must first get the value of key "response" like JSONObject tmp = (JSONObject) new JSONParser().parse(content);JSONObject resp = (JSONObject)tmp.get("response");

Jason Wang · Accepted Answer · 2018-12-19 02:36:39Z

-1

JSONArray schedulesArray = root.getJSONArray("schedules");

replace it with the following:

JSONObject response = root.getJSONObject("response");
JSONArray schedulesArray = response.getJSONArray("schedules");

then try again.

answered Dec 19, 2018 at 2:36

Jason Wang

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1 Comment

QWERTY Over a year ago

Nope it does not work. It is the same as the code snippet I just updated

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