Reading Nested Json in Java

[Satyajeet Kadam]

Q1) I passing nested Json to a Servlet.Format of my Json

{
    "DATA": [
        {
            "SelectType": "1",
            "create-new": "1",
            "size": "25",
            "size-unit": "GB",
            "port": "Port2",
            "group": "Default"
        }
    ]
}

I am reading this Json in a servlet

import java.io.*;
import java.text.*;
import javax.servlet.*;
import javax.servlet.http.*;
import net.sf.json.*;
import java.util.*;

public class register extends HttpServlet 
{
     public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException 
    {

          String userstr = readJSONStringFromRequest(request);
          JSONObject userjson = null;
         try {
                   userjson = JSONObject.fromObject(userstr);
                   System.out.println("satyaaaa===" + userjson);
               }
              catch(Exception pe)
             {
                 pe.printStackTrace();
              }


    }


    private String readJSONStringFromRequest(HttpServletRequest request) throws IOException
    {
         BufferedReader reader = request.getReader();
         StringBuilder sb = new StringBuilder();
          String line = reader.readLine();
          while (line != null) 
          {
              sb.append(line + "\n");
              line = reader.readLine();
          }
            reader.close();
            String data = sb.toString();

        return data;
    }

}

Output

satyaaaa==={"DATA":[{"SelectType":"1","create-new":"1","size":"25","size-unit":"GB","port":"Port2","group":"Default"}]}

Q2) How can i iterate this Json,to get the values of SelectType,create-new...etc?

[Duran Harris]

It depends whether you wish to manipulate the JSON on the client or server-side.

If you want to access the values in Java code you will need to download the json-lib.jar from json.org and add it to you're classpath.There is documentation on the site to assist you.You can give you're jsonString to the constructor of the JSONArray class and then use it's retrieval methods to access the values.

If you want to access the values in client-side javascript you can see examples of how to do it in plain javascript here :parsing JSON in javascript