Develop Reference

Java: Array of Arrays from JSON

I have a JSON Arrays of Array like this
"results": [
{
"id": "AAA",
"color": "#4D4837",
"links": {
"self": "https://aaa.com",
"html": "https://bbb.com",
"download": "https://ccc.com",
"download_location": "ddd.com"
},
"categories": [],
"likes": 3891,
},
{
"id": "BBB",
"color": "#4D453",
"links": {
"self": "https://abb.com",
"html": "https://bcc.com",
"download": "https://ccc.com",
"download_location": "ddd.com"
},
"categories": [],
"likes": 3000,
}
]
And I would like to retrieve "https://bbb.com" and "https://bcc.com" of "html", but I don't know how to do that.
Based on kindly comment, I put the following.
somehow, "getJSONObject()"can not be put. The error message says "Cannot resolve method 'getJSONObject' in 'JSONArray'".
JSONArray array = new JSONArray((Collection) jobjt.get("Strings"));
for (int i =0 ; i<2 ; i++){
JSONObject job = (JSONObject) array.get(i); --> get(i) can not be changed to getJSONObject(i)
String id = job.get("id").toString();
String color = job.get("color").toString();
String photoUrl = job.get("links").toString(); --> By updating here, I want to store only "https://bbb.com" and "https://bcc.com".
}
But when I tried to use the following, not only "html", but "self" and the other information are retrieved.
String photoUrl = job.get("links").toString();
Please tell me how to retrieve only "html".
I am using IntelliJ.

Steps to be followed(assuming you have proper JSONArray you mentioned):
get JSONObject from your JSONArray by index ie. for your case, index=0 here
Get the inner JSONObject by key of links
Now, access your content by key of html
Example for your case:
JSONObject indexedObject = jsonArray.getJSONObject(0);
JSONObject linksObject = indexedObject.getJSONObject("links");
String html= linksObject.getString("html");
Better keep checking if key exists as Harshal suggests

Return Java JsonPath as a json string

Using the java json path library: https://github.com/json-path/JsonPath
Given a json like this
{
"store": {
"book": [
{
"category": "reference"
},
{
"category": "fiction"
}
],
"bicycle": {
"color": "red",
"price": 19.95
}
},
"expensive": 10
}
I would like to return "book" as a list of strings. For examples:
List<String> results = JsonPath.read(example, "$.store.book[*]");
And results should look like:
["{\"category\":\"reference\"}", "{\"category\":\"fiction\"}"]
Is there a way to achieve this?
Currently:
System.out.println(udf.jsonExtractScalar(testExample, "$.store.book[*]").getClass().getName());
--> net.minidev.json.JSONArray

As book is a JsonArray in you json tree, you can use JsonArray type and retrieve the data from it and add to the list.
Here is an example.
JSONArray jsonArray = new JSONArray(jsonArrayString);
List<String> list = new ArrayList<String>();
for (int i=0; i<jsonArray.length(); i++) {
list.add( jsonArray.getString(i) );
Replace jsonArrayString with you jsondata's books array name and you will be good to go.
The class used will be JSONArray class which is
`org.json.JSONArray`

Parsing nested json array in java

I have json file in below format.
{
"data":[
{
"prjId": 1,
"name" : "Forj1",
"issue": [
{
"id": 00001,
"status" : "Closed"
},
{
"id": 00002,
"status" : "Open"
}
]
},
{
"prjId": 2,
"name" : "Forj2",
"issue": [
{
"id": 00003,
"status" : "Closed"
},
{
"id": 00004,
"status" : "Open"
}
]
}],
"issueCounter": 7,
"success": true
}
Here "data" is array of projects, and within project attribute there is array of "issue".
So far if I remove "issue" array, I am able to traverse the json to one level down in "data" attribute, If this json has "issue" array I get an error saying missing comma.
javax.json.stream.JsonParsingException: Invalid token=NUMBER at (line no=15, column no=14, offset=242) Expected tokens are: [COMMA]
Below is the code that I have right now. I have two problems with this, one is the error while reading if I place the "issue" attribute, and secondly a way to read the "issue" array and traverse all attributes within.
InputStream fis = new FileInputStream(pathToFile+"data3.json");
JsonReader jsonReader = Json.createReader(fis);
//the error is thrown on below line while reading the above json.
JsonObject jsonObject = jsonReader.readObject();
jsonReader.close();
fis.close();
System.out.println(jsonObject.getInt("issueCounter"));
//reading arrays from json
JsonArray jsonArrayData = jsonObject.getJsonArray("data");
Project [] prj = new Project[jsonArrayData.size()];
int index = 0;
for(JsonValue value : jsonArrayData){
JSONObject jsonObj = new JSONObject(value.toString());
System.out.println(jsonObj.getString("name"));
System.out.println(jsonObj.getInt("prjId"));
//this is also the place where I am stuck, I know I need to construct an array out of it by obtaining issue attribute. Below is very very wrong.
/*
JsonArray jsonArrayIssue = jsonObj.getJsonArray("issue");
for(JsonValue issue : jsonArrayIssue){
JSONObject jsonIssueObj = new JSONObject(issue.toString());
System.out.println(jsonIssueObj.getString("status"));
System.out.println(jsonIssueObj.getInt("id"));
}
*/
}
Any help or pointers is deeply appreciated. I can tweak the json if its required ultimately I need to maintain an array of issues.

The problem as others said is the JSON.
"id": 00001 <-- this is a number, numbers cannot start with a leading zero as per JSON stadard.
If you control the JSON you should tweak it.
Alternatively ff you don't, you can use a less strict parser like org.json.simple https://mvnrepository.com/artifact/com.googlecode.json-simple/json-simple
The code will be the same as yours, just adjusted to org.json.simple
try { ...
JSONObject rootJSON = (JSONObject) new JSONParser().parse(jsonString);
JSONArray dataList = (JSONArray) rootJSON.get("data");
for(Object projectObj: dataList.toArray()){
JSONObject project = (JSONObject)projectObj;
JSONArray issueList = (JSONArray) project.get("issue");
for(Object issueObj: issueList.toArray()){
JSONObject issue = (JSONObject) issueObj;
//do something with the issue
}
}
} catch (ParseException e) {
//do smth
e.printStackTrace();
}

Your json data is invalid.You can check here.
http://jsonlint.com
...issue": [{ "id": 00001,
"status": ----------------------^
Your id must be string number,string,boolean.Send 1,2,3,.... as return values and check if it works.

Your code looks okay the problem is the JSON formatting. Specifically the following lines:
"id": 00001,
"id": 00002,
"id": 00003,
"id": 00004,
Basically if you want it in that format you will need to set them as strings by wrapping the values in quotations i.e. "id": "00001" or you can use a valid number i.e. "id": 1

parse JSON to grab 'name' from an array

I'm trying to grab the 'name' from the JSON snippet I've included. I have tried the following but what I'm expecting is never grabbed.
Edit: 'output' is the full JSON string in case it wasn't already understood ;)
JSONObject result = null;
JSONArray data = null;
try {
try {result = new JSONObject(output);} catch (JSONException e) {e.printStackTrace();}
try {
data = result.getJSONArray("data");
for(int a=0;a<data.length();a++){
System.out.println(result.getJSONObject(String.valueOf(a)).getString("name"));//getJSONObject("results")
}
Here is the JSON snippet I'm trying to work with:
{
"code": 200,
"status": "Ok",
"copyright": "© 2015 MARVEL",
"attributionText": "Data provided by Marvel. © 2015 MARVEL",
"attributionHTML": "Data provided by Marvel. © 2015 MARVEL",
"etag": "b130a8b7af591e4e7ca078753f9c5c8a76e55e5d",
"data": {
"offset": 0,
"limit": 20,
"total": 1485,
"count": 20,
"results": [
{
"id": 1011334,
"name": "3-D Man",
"description": "",
"modified": "2014
.
.
.
.
.
.
.
.
.
.

To get you started, "data" points to a JSON Object, not array. So it should be:
data = result.getJSONObject("data");
Then, "results" points to a JSON array:
JSONArray results = data.getJSONArray("results");
Then you can try your loop. You shouldn't be turning a into a String - getJSONObject() takes an int for the index.
In case you're confused between Objects and Arrays, a JSON object has key - value pairs and are enclosed in curly braces. The keys are strings and the values can be a mix of any type:
{"key1": 5, "key2": "value2", "key3": {
"anotherObject": [1,2,3,4]
}
}
An array is a list of objects and is enclosed in square brackets:
[{...}, {...}, {...}]
The elements in the list don't have to be JSON objects, and in good JSON they will all be of the same type:
[1,2,3,4,4] or ["we", "are", "in", "an", "array"]

JSONTokener jsonTokener = new JSONTokener(jsonVaule);
JSONObject jsonObject = (JSONObject) jsonTokener.nextValue();
Int code =jsonObject.getInt("code");
String status =jsonObject.getString("status");
//{obejcet,obejcet,...}
for data{} is the same way~
JSONObject dataJsObject = (JSONObject) jsonObject.getJsonObject("data");
int offset =dataJsObject.getInt(""iffset);
....
//[{},{}] this type is jsonArrary
JSONArray results = dataJsObject.getJSONArray("results");
for(JSONObject resultJsonObj:JSONArray){
Int id =jsonObject.getInt("id");
//...and so on
}
hope it can help you~

You can parse like that
JsonObject obj = new JsonObject(StringResponse);
String code = obj.getString(code);
//same way you can get other string
JsonObject obj1 = obj.getJsonObject(Data);
String offset= obj.getString(offset);
//same way you can get other string
JsonArray jsonarr = obj1.getJsonArray(results);
for(i=0;i< jsonarr.size(); i++){
JsonObject innerObj = jsorr.getJsonObject(i);
String id= obj.getString(id);
//same way you can get other string
}
Hope It will helpful for you

Accessing json string in java and creating hashmap Android

I have a JSON string and I am trying to retrieve information from it. Json String looks like this.
JSON STRING :
{
"information": {
"device": {
"id": 0
},
"user": {
"id": 0
},
"data": [
{
"datum": {
"id": "00GF001",
"history_id": "9992BH",
"name": "abc",
"marks": 57,
"class": "B",
"type": "Student"
}
},
{
"datum": {
"id": "72BA9585",
"history_id": "78NAH2",
"name": "ndnmanet",
"marks": 70,
"class": "B",
"type": "Student"
}
},
{
"datum": {
"id": "69AHH85",
"history_id": "NN00E3006",
"name": "kit",
"department": "EF003",
"class": "A",
"type": "Employee"
}
},
{
"datum": {
"id": "09HL543",
"history_id": "34QWFTA",
"name": "jeff",
"department": "BH004",
"class": "A1",
"type": "Employee_HR"
}
}
]
}
}
I am trying to access data JSONArray and respective Datum from it. I differentiated each datum as per type such as student, employee etc and push information in hashmap.
I successfully did it in javascript but in Java I am struggle abit.
When I am trying to access JSONArray it throws exception
try {
JSONObject data = new JSONObject(dataInfo);
// Log.d(TAG, "CHECK"+data.toString());
JSONObject info = data.optJSONObject("information");
if(info.getJSONArray("data").getString(0).equals("Student") > 0) //exception here
Log.d(TAG, "Data"+ data.getJSONArray("data").length()); //exception here too
for(int m = 0; m < data.length(); m++){
// for(int s = 0; s < data[m].ge)
}
} catch (JSONException j){
j.printStackTrace();
}
Any pointers to create hashmap respective type I have. Appreciated

If you're trying to access the type field of a datum object, you'll want something like this:
JSONObject data = new JSONObject(dataInfo); // get the entire JSON into an object
JSONObject info = data.getJSONObject("information"); // get the 'information' object
JSONArray dataArray = info.getJSONArray("data"); // get the 'data' array
for (int i = 0; i < dataArray.length(); i++) {
// foreach element in the 'data' array
JSONObject dataObj = dataArray.getJSONObject(i); // get the object from the array
JSONObject datum = dataObj.getJSONObject("datum"); // get the 'datum' object
String type = datum.getString("type"); // get the 'type' string
if ("Student".equals(type)) {
// do your processing for 'Student' here
}
}
Note that you'll have to deal with exception handling, bad data, etc. This code just shows you the basics of how to get at the data that you're looking for. I separated each individual step into its own line of code so that I could clearly comment what is happening at each step, but you could combine some of the steps into a single line of code if that is easier for you.

if dataInfo is the json you posted, then you have to access information and from information, you can access data:
JSONObject data = new JSONObject(dataInfo);
JSONObject info = data.optJSONObject("information");
if (info != null) {
JSONArray dataArray = info.optJSONArray("data")
}