How do I extract value from Json

Question

I am getting a response String from server like below

{
  \"name\": \"Json\",
  \"detail\": {
    \"first_name\": \"Json\",
    \"last_name\": \"Scott\",
            


        

Answer 1

Use a JSON parser. There are plenty of JSON parsers written in Java.

http://www.json.org/

Look under the Java section and find one you like.

Answer 2

we can use the below to get key as string from JSON OBJECT

JsonObject json = new JsonObject(); 
 json.get("key").getAsString();

this gives the string without double quotes " " in the string

Answer 3

If you don't mind adding a dependency, you can use JsonPath.

import com.jayway.jsonpath.JsonPath;

String firstName = JsonPath.read(rawJsonString, "$.detail.first_name");

"$" specifies the root of the raw json string and then you just specify the path to the field you want. This will always return a string. You'll have to do any casting yourself.

Be aware that it'll throw a PathNotFoundException at runtime if the path you specify doesn't exist.

Answer 4

see this code what i am used in my application

String data="{'foo':'bar','coolness':2.0, 'altitude':39000, 'pilot':{'firstName':'Buzz','lastName':'Aldrin'}, 'mission':'apollo 11'}";

I retrieved like this

JSONObject json = (JSONObject) JSONSerializer.toJSON(data);        
    double coolness = json.getDouble( "coolness" );
    int altitude = json.getInt( "altitude" );
    JSONObject pilot = json.getJSONObject("pilot");
    String firstName = pilot.getString("firstName");
    String lastName = pilot.getString("lastName");

    System.out.println( "Coolness: " + coolness );
    System.out.println( "Altitude: " + altitude );
    System.out.println( "Pilot: " + lastName );

Answer 5

Pasting my code here, this should help. It shows the package which can be used.

import org.json.JSONException;
import org.json.JSONObject;

public class extractingJSON {

    public static void main(String[] args) throws JSONException {
        // TODO Auto-generated method stub

        String jsonStr = "{\"name\":\"SK\",\"arr\":{\"a\":\"1\",\"b\":\"2\"}}";
        JSONObject jsonObj = new JSONObject(jsonStr);
        String name = jsonObj.getString("name");
        System.out.println(name);

        String first = jsonObj.getJSONObject("arr").getString("a");
        System.out.println(first);

    }

}

Answer 6

String jsonErrorString=((HttpClientErrorException)exception).getResponseBodyAsString();
JSONObject jsonObj=null;
String errorDetails=null;
String status=null;
try {
        jsonObj = new JSONObject(jsonErrorString);
        int index =jsonObj.getString("detail").indexOf(":");
                errorDetails=jsonObj.getString("detail").substring(index);
                status=jsonObj.getString("status");

            } catch (JSONException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            item.put("status", status);
            item.put("errordetailMsg", errorDetails);