Hi developers,

                  I am getting 302, 401 & 404 status code errors from authentication to google api. what i am missing please help me 

public class GoogleCalendar
{
public void detail()
{
Http h = new Http();
HttpRequest req = new HttpRequest();
final string username = 'sreenath.sfdc@gmail.com';
final string password = 'Password';
//final string apikey='AIzaSyDaQK60dlM-7icVukY0sbaOHae9eLn3dKk';
Blob headerValue = Blob.valueOf(username + ':' + password);
String authorizationHeader = 'BASIC ' +EncodingUtil.base64Encode(headerValue);
// auth url is https://www.googleapis.com/auth/calendar
req.setHeader('Authorization',authorizationHeader);
req.setHeader('Connection','keep-alive');
req.setHeader('Host','googleapis.com');
req.setHeader('Content-Type', 'application/Json');
req.setMethod('GET');
req.setbody('https://www.googleapis.com/auth/calendar?key=AIzaSyDaQK60dlM-7icVukY0sbaOHae9eLn3dKk');
//req.setbody(apikey);
req.setEndpoint('https://www.googleapis.com/calendar/v3/calendars/calendarId');
//req.setEndpoint('https://www.googleapis.com/calendar/v3/calendars/sreenath.sfdc@gmail.com/events/tea%20time?pp=1&key=AIzaSyDaQK60dlM-7icVukY0sbaOHae9eLn3dKk');
HttpResponse res = h.send(req);
system.debug('********'+res.getbody());
}

}