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Java: Gson parse without square brackets

I have a JSON file that I'm trying to parse that doesn't have surrounding square brackets: [...].
Here is the Java code. (This has the Gson dependency in Maven) I keep on getting the error on line 29, "This is not a JSON Array." However, when I add square brackets to the beginning and end of the JSON file, it parses just fine. How can I parse this without the brackets.
Here is the JSON:
{
"title": "Title",
"content": "whatever",
"author": "Yuki Noguchi",
"date_published": "2017-02-15T20:25:00.000Z",
"lead_image_url": "https://media.npr.org/assets/img/2017/02/15/ap_17039860769171_wide-d1a5d3c17f00d78fd1df9d19a96e1d7b3bd38e60.jpg?s=1400",
"dek": null,
"next_page_url": null,
"url": "http://www.npr.org/2017/02/15/515425370/trump-labor-pick-andrew-puzders-nomination-appears-in-jeopardy",
"domain": "www.npr.org",
"excerpt": "The fast-food CEO faced fierce opposition from labor groups, plus personal controversies. Ultimately, he didn't have support from enough Republican senators.",
"word_count": 751,
"direction": "ltr",
"total_pages": 1,
"rendered_pages": 1
}
Thanks!

Try this one, append "[" open and "]" close braces and store in temporary variable and pass that temporary variable to parse.
for example,
var jsonVar = { name:"hello", title: "WOrld" };
var tmpJsonVar = "[" + jsonVar + "]";
var jsonObject = JSON.parse(tmpJsonVar);

Converting Nested Json files to CSV in java

{
"Employee": [
{
"empMID": "mock:1",
"comments": [],
"col1": "something",
"contact": [{"address":"2400 waterview", "freetext":true}
],
"gender": "male"
},
{
"empMID": "mock:2",
"comments": [],
"col1": "something",
"contact": [{"address":"2200 waterview", "freetext":true}
],
"gender": "female"
}
],
"cola": false,
"colb": false
}
This is how my Json file looks .I m required to convert this json to a csv .(I m trying to convert a multi-dimesional data to 2d).I m using gson for my purpose.I cannot use gson.fromgson() function to object map with a template because it should be generic .
I know we can use CDL to convert jsonarray to csv format but It wont work in my case .
my csv format looks like
Employee*
empMID,comment.$,contact.address,contact.freetext,gender
mock:1,,2400 waterview,TRUE,male
mock:123,,2200 waterview,TRUE,female
colA#
TRUE
colB#
FALSE
I tried using google-GSON api to convert to this format .But I m not able to convert to this format .I have used * to represent its a json array and # to represent its a primitive type and contact.address to represent nested array inside another json array .I having problem relating this nested structure .I m able to traverse everything recursively like a column. Thanks in advance
public static void main(String[] args) throws IOException{
BufferedReader reader=null;
StringBuilder content=null;
String result=null;
reader = new BufferedReader(new FileReader("temp.json"));
String line = null;
content= new StringBuilder();
while ((line = reader.readLine()) != null) {
content.append(line);
}
reader.close();
result= content.toString();
JsonElement jelement = new JsonParser().parse(result);
printJsonRecursive(jelement);
}
public static void printJsonRecursive(JsonElement jelement){
if(jelement.isJsonPrimitive()){
System.out.println(jelement.getAsString());
return;
}
if(jelement.isJsonArray()){
JsonArray jarray= jelement.getAsJsonArray();
for(int i=0;i<jarray.size();i++){
JsonElement element= jarray.get(i);
printJsonRecursive(element);
}
return;
}
JsonObject jobject= jelement.getAsJsonObject();
Set<Entry<String, JsonElement>> set= jobject.entrySet();
for (Entry<String, JsonElement> s : set) {
printJsonRecursive(s.getValue());
}
}
}

You can achieve this thru reflection if you have a object mapped to the json.
use gson/jackson to convert json to java object
append fields using reflection by iterating the class and get any field you interested in.
append value with reflection by getting value from the target object.
More detail look at my blog post below:
vcfvct.wordpress.com/2015/06/30/converting-nested-json-files-to-csv-in-java-with-reflection/

You are not printing the key. This should fix it.
for (Entry<String, JsonElement> s : set) {
System.out.println(s.getKey()); //Added
printJsonRecursive(s.getValue());
}
You can take care of \ns from here.
EDIT
If you want to print the keys just once for repeating json objects, create a Java bean to hold the data and populate it during your recursion. Once the bean is complete, add a method there to print all the data in the format you want (printing keys only once and so on).

You can use the library json2flat for converting your JSON to CSV.
This library doesn't require any POJO's. It simply takes your JSON as string and returns a 2D representation of it in the format of List<Object[]>.
For example for the JSON:
{
"Employee": [
{
"empMID": "mock:1",
"comments": [],
"col1": "something",
"contact": [{"address":"2400 waterview", "freetext":true}
],
"gender": "male"
},
{
"empMID": "mock:2",
"comments": [],
"col1": "something",
"contact": [{"address":"2200 waterview", "freetext":true}
],
"gender": "female"
}
],
"cola": false,
"colb": false
}
It gives an output:
/cola,/colb,/Employee/empMID,/Employee/col1,/Employee/gender,/Employee/contact/address,/Employee/contact/freetext
,,"mock:1","something",,"2400 waterview",true
,,"mock:2","something",,"2200 waterview",true
false,false,,,,,

/**
* Get separated comlumns used a separator (comma, semi column, tab).
*
* #param headers The CSV headers
* #param map Map of key-value pairs contains the header and the value
*
* #return a string composed of columns separated by a specific separator.
*/
private static String getSeperatedColumns(Set<String> headers, Map<String, String> map, String separator) {
List<String> items = new ArrayList<String>();
for (String header : headers) {
String value = map.get(header) == null ? "" : map.get(header).replaceAll("[\\,\\;\\r\\n\\t\\s]+", " ");
items.add(value);
}
return StringUtils.join(items.toArray(), separator);
}

Parsing generic tag in JSON from GSON

I have a JSON which contains generic values. I tried it by using Maps but couldn't get the results. My problem is the generic tags starts from second level. Here is the JSON I am trying to parse through gson.
{
"success": true,
"status": 200,
"events": {
"Sep 2013": [
{
"artist_id": 1,
"created_at": "2013-05-18T15:21:00Z",
"duration": 2,
"end_time": "2013-09-19T22:00:00Z",
"event_desc": "",
"event_facebook_link": "",
"event_link": "https://www.smtickets.com/marketing/view/1316",
"feature_small": false,
"featured_status": false,
"id": 90,
In this JSON tag after "events" is generic i.e., "Sep 2013".
What I am trying right now is:
public Event event ;
public class Event {
public ArrayList<Map<String, String>> dates;
}
And I'm accessing it:
obj = gson.fromJson(reader, AllShowsActivityData.class);
Can anyone tell me that how can I make a class of dates. So Gson can serialize it. Or is there any other way to iterate first level tag and then I can declare it something like this
Type fooType = new TypeToken<Foo<Bar>>() {}.getType();
gson.toJson(foo, fooType);

You can indeed use a Map, but you're not using it correctly. Note that what you have is a field "events", which is an object that contains a number of pairs string and array of objects:
{ "events": { "Sep 2013": [ {}, {}, ... ], ... } }
To parse your JSON you'd need a class structure like this (in pseudo-code):
class AllShowsActivityData
Map<String, List<Event>> events
class Event
int artist_id
String created_at //parsing as String to simplify...
int duration
...
And then your code to parse:
AllShowsActivityData obj = gson.fromJson(reader, AllShowsActivityData.class);
And finally, if what you want is to access the dates, you'll have all of them in:
Set<String> dates = obj.getEvents().keySet(); //"Sep 2013", ...
Note: in fact, if you only want those dates, you don't even need the class Event and you could use just Map<String, List<Object>> events...

GAE Datastore Text messes up JSON representation

The following code excerpt builds a Google App Engine Datastore Entity from a Java Map. Short strings (less than 450 characters) are stored directly, long strings are converted to Text objects.
for (String key : movieMap.keySet()) {
String value = movieMap.get(key).trim();
if (value.length()>0 && value.length()<450) { // Short String - store as is
movieEntity.setProperty(key, value);
} else if (value.length()>=450) { // Long String - convert to text
movieEntity.setProperty(key, new Text(value));
}
}
The following code retrieves the Entity as a Json object:
Map<String, Object> result = new LinkedHashMap<String, Object>();
result.put("numberOfMovies", String.valueOf(movies.size()));
result.put("movies", movies);
Gson gson = new GsonBuilder().setPrettyPrinting().create();
resp.getWriter().print(gson.toJson(result));
The result JSON for a String description fields:
{
"propertyMap": {
"title": "טאנו מתחתנת עם מאנו - Tanu Weds Manu",
"duration": "154 דקות",
"movieId": "2315",
"image_url": "http://www.sderot-cin.org.il/media/sal/movies2009/2315/f18_tano mithatenet iim mano.jpg",
"description": "סינמסטה - מועדון הסרט ההודי רופא ממוצא הודי חוזר מלונדון במטרה לפגוש את כלתו המיועדת. הוא מופתע לגלות כי היא מאוהבת במישהו אחר ואין בכוונתה להינשא לו. התנהגותה הפראית גורמת לו לשקול מחדש את צעדיו.",
"explorationDate": "Apr 26, 2013 8:42:36 PM",
"actors": "קנגנה רנאוט, אר מדווהין",
"year": "2011",
"language": "הינדית",
"director": "אנאנד ראי",
"country": "הודו"
}
},
{
The result JSON for a Text description fields, with a strange inner dictionary:
"propertyMap": {
"title": "הנעליים של אדון סימון - הצגת תיאטרון לילדים",
"movieId": "2316",
"image_url": "http://www.sderot-cin.org.il/media/sal/movies2009/2316/f18_anaaliim shel adon simon.jpg",
"description": {
"value": {
"value": "תיאטרון אורנה פורת לגילאי 3-7 אדון סימון עוזב את ארצו ועובר לגור בארץ אחרת. בביתו החדש הוא מחליט להיפרד מנעליו הישנות שליוו אותו כל חייו ולהחליפן בנעליים חדשות, אך משום מה הוא לא מצליח להיפטר מהישנות. בכל פעם שהוא זורק אותן, רחוק ככל שיהיה, הן תמיד חוזרות אליו בדרך פלא. הצגה מרגשת ומצחיקה שמלמדת אותנו לקבל בשמחה את הדברים החדשים שבחיינו ובאותו זמן להבין שאפשר גם להתגעגע לדברים הישנים. משך ההצגה כ50 דקות. כרטיסים: מכירה מוקדמת-30 ₪, ביום ההצגה-40 ₪ מנוי/מלווה : מכירה מוקדמת 20 ₪, ביום ההצגה 30 ₪."
}
},
"explorationDate": "Apr 26, 2013 8:42:36 PM"
}
},
The problem is that the description field returns normaly (key:value pair) for String field, but has a strange inner value key for Text fields - compare description in both examples.
Any idea how can I make Text fields behave normally and appear as the standard

Looks like the inner dictionary is a result of serializing the complex GAE Datastore Text object.
Since you're accessing your fields of your data with keys then I guess annotations and some getter/setter methods isn't possible?
In such case a simple way to fix it may be to iterate through the Map after it is retrieved and set (replace) the Text "description" fields with standard String if they were of type Text.
Then when you serialize to JSON those strings will be handled as the other strings.

Parsing JSON data in Java for Android

I hope someone might be able to help me.
I am trying to parse following json file:
{"seminar":[
{"categoryid": "1","cpe": "13","inventory":["Discussion","Value x","Value y"
],"teachers": [
{
"titel": "Dipl.-Ing.",
"company": "XY",
"name": "Test",
"id": "3",
}
],
},...
I am lost with parsing the teachers data in...
...
private static final String TAG_teachers = "teachers";
private static final String TAG_TITLE = "title";
for(int i = 0; i < seminar.length(); i++){
JSONObject c = seminar.getJSONObject(i);
...
teachers = c.getJSONArray(TAG_DOZENTEN);
for(int z = 0; z < teachers.length(); z++){
JSONObject d = teachers.getJSONObject(z);
String title = d.getString(TAG_TITLE);
Log.d("JSONParsingActivity", title);
I get the error System.err(1010): org.json.JSONException: Value null
at teachers of type org.json.JSONObject$1 cannot be converted to
JSONArray.
What did I do wrong? As I understand from the JSON documentation, teachers is an JSON Array and not an Object. Is somebody able to help me?

You have an extra (trailing) comma in teachers (after "3"). Not allowed in JSON. Remove it and see if that helps.

If your JSON is really of the form:
{ ... }, { ... }, { ... }, ...
This is invalid JSON
The root enclosure must either be a single object (in {}) or an array (in []).
If your intent is to send an array of objects, then simply wrap the entire thing with square brackets to make it an array and create a JSONArray object from it.
So it must be like this
[ { ... }, { ... }, { ... }, ... ]
You also need to make sure that you don;t have extra commas, unclosed brackets, etc. Use JSONLint or other similar JSON format checker to save yourself some time in finding syntax problems.