read a json file java code example

Example 1: java load .json file

import net.sf.json.JSONObject;
import net.sf.json.JSONSerializer;
import org.apache.commons.io.IOUtils; 

    public class JsonParsing {

        public static void main(String[] args) throws Exception {
            InputStream is = 
                    JsonParsing.class.getResourceAsStream( "sample-json.txt");
            String jsonTxt = IOUtils.toString( is );

            JSONObject json = (JSONObject) JSONSerializer.toJSON( jsonTxt );        
            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 );
        }
    }

Example 2: java load .json file

package com.howtodoinjava.demo.jsonsimple;
 
import java.io.FileWriter;
import java.io.IOException;
 
import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
 
public class WriteJSONExample
{
    @SuppressWarnings("unchecked")
    public static void main( String[] args )
    {
        //First Employee
        JSONObject employeeDetails = new JSONObject();
        employeeDetails.put("firstName", "Lokesh");
        employeeDetails.put("lastName", "Gupta");
        employeeDetails.put("website", "howtodoinjava.com");
         
        JSONObject employeeObject = new JSONObject(); 
        employeeObject.put("employee", employeeDetails);
         
        //Second Employee
        JSONObject employeeDetails2 = new JSONObject();
        employeeDetails2.put("firstName", "Brian");
        employeeDetails2.put("lastName", "Schultz");
        employeeDetails2.put("website", "example.com");
         
        JSONObject employeeObject2 = new JSONObject(); 
        employeeObject2.put("employee", employeeDetails2);
         
        //Add employees to list
        JSONArray employeeList = new JSONArray();
        employeeList.add(employeeObject);
        employeeList.add(employeeObject2);
         
        //Write JSON file
        try (FileWriter file = new FileWriter("employees.json")) {
 
            file.write(employeeList.toJSONString());
            file.flush();
 
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}