Convert JSONArray to arrayList

Question

I'm trying to convert a JSONArray which looks like this :

{"output":["name":"Name3","URI":"Value3"},{"name":"Name5","URI":"Value5"},{"name":"Name4","URI":"Value4"}]}

Into an arrayList so for example the output of Arr[0][0] will be Name3

I have tried this solution:

if (outputs!= null) { 
    int len = outputs.length();
    for (int j=0;j<len;j++){ 
        list.add(outputs.get(j).toString());
    } 
} 
for (String str : list) {               
    System.out.println("Item is: " + str);              
}

But I get the full row : {"name":"Name3","URI":"Value3"}

How can I get each object of my JSONArray?

@maxZoom I have seen this and it does not solve my problem but thank you anyway for pointing this out . I can do that but i want to send the full array as an argument — azelix
– azelix, Commented May 18, 2015 at 14:32

Dmitry Ginzburg · Accepted Answer · 2017-11-13 09:13:55Z

3

It is not specified, which JSON parser do you use, so I suppose you can choose right now and I'll suggest using Gson as such.

The better solution for deserializing such a structures is creating a special class for each structure, for example:

public class NameURIPair {
    private String name;
    private String URI;

    // getters
}

Then your JSON can be deserialized into a class, which holds the resulting List in it:

public class Data {
    private List<NameURIPair> output;

    // getter
}

// ...

Data data = new Gson(stringData, Data.class);

Since you've requested the other way, you still can get just the parsed JSON into JsonElement with JsonParser

JsonElement root = new JsonParser().parse(stringData);

Although I won't give you the full solution not to appreciate this kind of solutions :-)

edited Nov 13, 2017 at 9:13

answered May 18, 2015 at 14:51

Dmitry Ginzburg

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Comments

MaxZoom · Accepted Answer · 2015-05-18 14:58:28Z

2

Aazelix, your Json output seem to be missing opening array bracket. Its correct form is listed below:

{"output":[{"name":"Name3","URI":"Value3"},{"name":"Name5","URI":"Value5"},{"name":"Name4","URI":"Value4"}]}

As for the conversion to POJO

List<MyObj> list = new ArrayList<>();
if (outputs!= null) { 
  int len = outputs.length();
  for (int i=0; i<len; i++) { 
    JSONObject o = (JSONObject) outputs.get(i);
    list.add(new MyObj(o.getString('name'), o.getString('URL')));
  } 
} 
System.out.println("There is " + list.size() + " objects.");


public static final class MyObj {
  final String name;
  final String url;

  public MyObj(String name, String url) {
     this.name = name;
     this.url  = url;
  }
}

edited May 18, 2015 at 14:58

answered May 18, 2015 at 14:50

MaxZoom

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3 Comments

Dmitry Ginzburg Over a year ago

o.name; o.URL. Really?

Dmitry Ginzburg Over a year ago

second poing: OP had URI, not URL

MaxZoom Over a year ago

I did not compile nor run the code so it may need some improvements.

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