How to convert json String to java object

Question

From jsp through ajax cal I'm passing json string to server and I am converting to json object. How can I convert the jsonobject to a model class object in java?

In server I'm doing this:

 HttpServletRequest request = ServletActionContext.getRequest();
 String jsonData = request.getParameter("JsonData");
 JSONObject jsonDataObject = (JSONObject) JSONSerializer.toJSON( jsonData );

My model classes looks like this:

   public class Vehicles {

private List<Vehicle> vehicle;

public List<Vehicle> getVehicle() {
    return vehicle;
}

public void setVehicle(List<Vehicle> vehicle) {
    this.vehicle= vehicle;
}

    }

And

  public class Vehicle{
    private Integer vId;
   private String VName;
    private List<Department> department;
   //getters and setters;
    }

and

  public class Department{
    private Integer depId;
private String departmentName;
private List<Item> item;
   //getters and setters
   }

and

  public class Item{
  private Integer itemId;
  private String itemName;
  //getters and setters
   }

and I am getting jsonData String as

{"vehicles":[{"vehicle":[{"department":[{"Item":[{"itemId":31,"itemName":"c7"},{"itemId":32,"itemName":"c2"}],"depId":21,"departmentName":"d1"}],"vId":11,"VName":"aaa"},{"department":[{"Item":[{"itemId":33,"itemName":"c3"},{"itemId":34,"itemName":"c4"}],"depId":22,"departmentName":"d2"},{"Item":[{"itemId":36,"itemName":"c1"}],"depId":24,"departmentName":"d3"}],"vId":12,"VName":"bbbb"},{"department":[{"Item":[{"itemId":30,"itemName":"c6"},{"itemId":35,"itemName":"c5"}],"depId":23,"departmentName":"d4"}],"vId":13,"VName":"cccc"},{"department":[{"Item":[{"itemid":37,"itemName":"c8","status":0}],"depId":25,"departmentName":"d5"}],"vId":14,"VName":"ddd"}]}]}

How can I convert JSONObject jsonDataObject ( or String jsonData) to model class object(ie vehicles) in java?

Answer 1

use this..

  import org.codehaus.jackson.map.ObjectMapper;
  import org.json.JSONException;
  import org.json.JSONObject; 


HttpServletRequest request = ServletActionContext.getRequest();
Vehicles vehicles;
String jsonData = request.getParameter("JsonData");
jsonData = jsonData.substring(13, jsonData.length()-2);
ObjectMapper mapper = new ObjectMapper();
try{
    vehicles= mapper.readValue(jsonData, Vehicles.class);
}
catch (Exception e) {
    e.printStackTrace();
}

Answer 2

For converting (String jsonData), i prefer Gson

Its like,

 Gson gsonObj = new Gson();
 Vehicles vehicles = gsonObj.fromJson(jsonData, Vehicles.class);
 iterate through this list