How to Create JSONArray for a List

Question

I have a class called

class Student {
   String name;
   String age;
}

I have a method that returns List object like

publi         


        

Answer 1

You will have to include the jettison jar in you project and import the required classes.

JSONObject jObject = new JSONObject();
try
{
    JSONArray jArray = new JSONArray();
    for (Student student : sudentList)
    {
         JSONObject studentJSON = new JSONObject();
         studentJSON.put("name", student.getName());
         studentJSON.put("age", student.getAge());
         jArray.put(studentJSON);
    }
    jObject.put("StudentList", jArray);
} catch (JSONException jse) {
    jse.printStacktrace();
}

Answer 2

I think you need not download the jettison jar file.

Using JSONArray and JSONObject you can easily convert that list into JSON object like @Juniad answer

Answer 3

When you want to map Object to json directly or want to convert json to object, you can use GSON library . this will give you more flexibility and control.

Download link - http://code.google.com/p/google-gson/

Tutorial link - http://www.mkyong.com/java/how-do-convert-java-object-to-from-json-format-gson-api/

Answer 4

Using Gson Library it will be very simple.

From JSON String to ArrayList of Object as:

Type listType = 
     new TypeToken<ArrayList<Student>>(){}.getType();
ArrayList<Student> yourClassList = new Gson().fromJson(jsonArray, listType);

And to Json from Array List of Object as:

ArrayList<Student> sampleList = new ArrayList<Student>();
String json = new Gson().toJson(sampleList);

The Gson Library is more simple to use than JSONObject and JSONArray implementation.

Answer 5

try gson: Serializing-and-Deserializing-Generic-Types

Answer 6

Create JSONArray like below.

JSONArray jsArray = new JSONArray(arrayList);