Develop Reference

JSON Object GSON into list

I want to implement my old code when I was populating JSON array into listview but my current json haven't specified array, overall json is an array...
Can somebody tell me how to transform my code to use JSON like this?
https://api-v2.hearthis.at/categories/drumandbass/?page=15&count=2
Code to use gson, my old:
protected List<Model> doInBackground(String... params) {
HttpURLConnection connection = null;
BufferedReader reader = null;
try {
URL url = new URL(params[0]);
connection = (HttpURLConnection) url.openConnection();
connection.connect();
InputStream stream = connection.getInputStream();
reader = new BufferedReader(new InputStreamReader(stream));
StringBuffer buffer = new StringBuffer();
String line ="";
while ((line = reader.readLine()) != null){
buffer.append(line);
}
String finalJson = buffer.toString();
JSONObject parentObject = new JSONObject(finalJson);
JSONArray parentArray = new JSONArray("arrayname");
List<Model> dataModelList = new ArrayList<>();
Gson gson = new Gson();
for(int i=0; i<parentArray.length(); i++) {
JSONObject finalObject = parentArray.getJSONObject(i);
Model modelList = gson.fromJson(finalObject.toString(), Model.class);
dataModelList.add(modelList);
}
return dataModelList;
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (JSONException e) {
e.printStackTrace();
} finally {
if(connection != null) {
connection.disconnect();
}
try {
if(reader != null) {
reader.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
return null;
}

Instead of doing this:
JSONObject parentObject = new JSONObject(finalJson);
JSONArray parentArray = new JSONArray("arrayname");
Just do this:
JSONArray parentArray = new JSONArray(finalJson);

If i understand the problem correctly, i guess you are having trouble parsing the array who's name is not specified with a key. So, a simple but not a very good way of doing this would be, when you create your finalJson like this:
String finalJson = buffer.toString();
just add a line to check if it contains an array opening bracket, like this:
if(finalJson.contains("[")){
finalJson = finalJson.replace("[","{
"arrayname": [");
}
also, close the array appropriately.
if(finalJson.contains("]")){
finalJson = finalJson.replace("]","]
}");
}
This way, u will have a name for the array to parse, and i guess this is what you are looking for. But this approach might fail if you have more than 1 array in your Json, in that case you will have to use startsWith & endsWith string methods to give a name to your array. But, as of now, from what your Json looks like, this would work.

Spring MVC can not fetch JSON value

In Spring mvc I have a mytable.json file.
I want to fetch that json file data and then want to add to model.addAttribute().
mytable.json
{"name1":["place1.1","place1.2"],
"name2":["place2.1","place1.2"]
...........
.........}
I want to fetch the names with their corresponding citylist.
Ex:
name1=place1.1,place1.2
so,I have done:--
try {
JSONParser parser = new JSONParser();
ClassLoader classLoader = getClass().getClassLoader();
File file = new File(classLoader.getResource("file/mytable.json").getFile());
JSONObject obj = (JSONObject) parser.parse(new FileReader(file));
Iterator<String> keys = obj.values().iterator();
while( keys.hasNext() )
{
String key = (String)keys.next();
if ( obj.get(key) instanceof JSONObject )
{
model.addAttribute("key", key);
}
}
} catch (Exception e) {
e.printStackTrace();
}
But I am getting error:
Unexpected character (�) at position 0.
in this line :
JSONObject obj = (JSONObject) parser.parse(new FileReader(file));
why??Where is the problem?

The JSONParser parser = new JSONParser(); is expecting a JSON String, not a .json file. hence the Unexpected character.... error.
You can InputStreamReader:
jsonObject = (JSONObject) parser.parse(new InputStreamReader(new FileInputStream("file/mytable.json")));

AutoSuggest in Android from jsonencoded array of php

I want to use json encoded array which i am return from this link :
http://sids.roundone.asia/suggest.json?data=soft
as suggestions in android application.
(I have used json_encode($arr) function in php file and i am returning that as response for above link)
I have a problem in reading this response in java and storing it in an ArrayList.
My code is :
try {
String temp=sName.replace(" ", "%20");
URL js = new URL("https://sids.roundone.asia/suggest.json?data="+temp);
URLConnection jc = js.openConnection();
BufferedReader reader = new BufferedReader(new InputStreamReader(jc.getInputStream()));
String line = reader.readLine();
JSONObject jsonResponse = new JSONObject(line);
JSONArray jsonArray = jsonResponse.getJSONArray("results");
for(int i = 0; i < jsonResponse.length(); i++){
JSONObject r = jsonArray.getJSONObject(i);
ListData.add(new SuggestGetSet(jsonResponse.get(String.vlaueOf(iss)));
}
}

As I could see on your link, you're returning a JSON Array, instead of a JSON Object, ( "[ ]" instead of "{ }") and then in your java code you're trying to create a JSONObject here:
JSONObject jsonResponse = new JSONObject(line);
Try changing that to:
JSONArray jsonResponse = new JSONArray(line);

You return JSON array directly not a JSON Object have inner array so cast your incoming response to JSONArray directly.
JSONArray jsonResponse = new JSONArray(line);

The method getJSONObject(String) is undefined for the type JSONObject

I am returning a json from my class:
#POST("/test")
#PermitAll
public JSONObject test(Map form) {
JSONObject json=new JSONObject();
json.put("key1",1);
json.put("key2",2);
return json;
}
now I want to get this json from "getInputStream" and parse it to see if key1 exists:
String output = "";
BufferedReader reader = new BufferedReader(new InputStreamReader(con.getInputStream()));
StringBuilder output = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
output.append(line + "\n");
}
output=output.toString();
JSONObject jsonObj = new JSONObject();
jsonObj.put("output", output);
if (jsonObj.get("output") != null){
**//search for key1 in output**
System.out.println("key1 exists");
}else{
System.out.println("key1 doesnt exist");
}
reader.close();
How can I convert output to JSONObject and search for "key1"?
I tried following but I got errors after arrows:
JSONObject jObject = new JSONObject(output); ---> The constructor JSONObject(String) is undefined
JSONObject data = jObject.getJSONObject("data"); ---> The method getJSONObject(String) is undefined for the type JSONObject
String projectname = data.getString("name"); ----> The method getString(String) is undefined for the type JSONObject

JSONObject jsonObject = (JSONObject) JSONValue.parse(output);
Try this.
And then you can verify the existence of the field using:
jsonObject.has("key1");

You need to parse the object using a parser. Check out the documentation here: https://code.google.com/p/json-simple/wiki/DecodingExamples

JSON Data Formatting

I am passing the following JSON object from a .jsp page to a java servlet using JSON.stringify and JQuery.ajax():
{"bin":[{"binId":"0","binDetails":[{"productCode":"AU192","qty":"4"},{"productCode":"NE823","qty":"8"}],"comments":"store pickup"},{"binId":"1","binDetails":[{"productCode":"AF634","qty":"2"}],"comments":""},{"binId":"2","binDetails":[{"productCode":"QB187","qty":"3"}],"comments":"international shipping"},{"binId":"3","binDetails":[{"productCode":"AF634","qty":"2"},{"productCode":"QB187","qty":"2"}],"comments":""}]}
This is the code in my java servlet:
StringBuffer strBuffer = new StringBuffer();
String line = null;
try {
BufferedReader reader = request.getReader();
while((line = reader.readLine()) != null){
strBuffer.append(line);
}
} catch (Exception e) {
}
try {
JSONObject jsonObj = new JSONObject(new JSONTokener(strBuffer.toString()));
// I call a method here and pass jsonObj
} catch (Exception e) {
}
In the method to which I pass jsonObj I am using jsonObj.length() to find out how many items are in jsonObj and it tells me 1, which in this case I would have expected 3. I even tried this:
JSONObject bins = jsonObj.get("bin");
bins.length();
which told me jsonObj.get("bin") was not a JSONObject. Is my data formatted incorrectly before I pass it from my .jsp or am I using the JSONObject in my java servlet incorrectly? How do I access the values in the JSONObject?

JSONArray bins = jsonObj.getJSONArray("bin");
bins.length();