Question

What would be the easiest way to load a file containing JSON into a JSONObject.

At the moment I am using json-lib.

This is what I have, but it throws an exception:

XMLSerializer xml = new XMLSerializer();
JSON json = xml.readFromFile("samples/sample7.json”);     //line 507
System.out.println(json.toString(2));

The output is:

Exception in thread "main" java.lang.NullPointerException
    at java.io.Reader.<init>(Reader.java:61)
    at java.io.InputStreamReader.<init>(InputStreamReader.java:55)
    at net.sf.json.xml.XMLSerializer.readFromStream(XMLSerializer.java:386)
    at net.sf.json.xml.XMLSerializer.readFromFile(XMLSerializer.java:370)
    at corebus.test.deprecated.TestMain.main(TestMain.java:507)

Answer 1

try this:

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 );
        }
    }

and this is your sample-json.txt , should be in json format

{
 'foo':'bar',
 'coolness':2.0,
 'altitude':39000,
 'pilot':
     {
         'firstName':'Buzz',
         'lastName':'Aldrin'
     },
 'mission':'apollo 11'
}