'How to Create JSONArray for a List<Class name>

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?

javajsonlistarraylist


Solution 1:[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.

Solution 2:[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();
}

Solution 3:[3]

Create JSONArray like below.

JSONArray jsArray = new JSONArray(arrayList);

Solution 4:[4]

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

Solution 5:[5]

json-lib is likely the library you are looking for. you can find som examples of usage here.

Solution 6:[6]

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/

Solution 7:[7]

You can use ObjectMapper from 'com.fasterxml.jackson.core' like this

List<Student> list = Arrays.asList(new Student("sam", "12"), new Student("sri", "5"));
ObjectMapper objectMapper = new ObjectMapper();
String listAsString = objectMapper.writeValueAsString(list));

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution Source
Solution 1
Solution 2 Mandar Pandit
Solution 3 vitralyoz
Solution 4 Alex Stybaev
Solution 5 W. Goeman
Solution 6 kundan bora
Solution 7 mahfuj asif

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