How to Create JSONArray for a List<Class name>

Question

I have a class called

class Student {
   String name;
   String age;
}

I have a method that returns List object like

public List<Student> getList(){

 List<Student> li =new ArrayList();
 ....

 li.add(new Student('aaa','12'));
 ... 

 return li;    
}

I need to convert that list into JSONArray like this

[{"name":"sam","age":"12"},{"name":"sri","age":"5"}]

Can anyone help me to get this?

Answer 1

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 2

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();
}