Add Google calendar event without OAuth in Java?

Question

I want to add an event to a google calendar in Java. I don't want to use OAuth which is web based one. Using simple java code i want to add an event, the authentication for google calendar i use is static. My application generates events and posts to Google calendar. I use the following code to create an event and post to calendar.

Event event = new Event();

event.setSummary("Appointment");
event.setLocation("Somewhere");

ArrayList<EventAttendee> attendees = new ArrayList<EventAttendee>();
attendees.add(new EventAttendee().setEmail("attendeeEmail"));
// ...
event.setAttendees(attendees);

Date startDate = new Date();
Date endDate = new Date(startDate.getTime() + 3600000);
DateTime start = new DateTime(startDate, TimeZone.getTimeZone("UTC"));
event.setStart(new EventDateTime().setDateTime(start));
DateTime end = new DateTime(endDate, TimeZone.getTimeZone("UTC"));
event.setEnd(new EventDateTime().setDateTime(end));

Event createdEvent = service.events().insert("primary", event).execute();

System.out.println(createdEvent.getId());  

I have gone through the following links which explains about web OAuth. But i don't need such a complex thing.Google Service creation

How can i get the service object here ???
Please help me if anyone knows and example code is highly appreciated

Answer 1

Following code worked for me, Service class is

import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.nio.charset.Charset;
import java.util.Collections;

import com.google.api.client.googleapis.auth.oauth2.GoogleCredential;
import com.google.api.client.http.HttpTransport;
import com.google.api.client.http.javanet.NetHttpTransport;
import com.google.api.client.json.JsonFactory;
import com.google.api.client.json.jackson2.JacksonFactory;
import com.google.api.services.calendar.Calendar;
import com.google.api.services.calendar.CalendarScopes;
import com.google.common.io.Files;

/**
 * @author Yaniv Inbar
 */
public class CalendarService {

  /**
   * Be sure to specify the name of your application. If the application name is {@code null} or
   * blank, the application will log a warning. Suggested format is "MyCompany-ProductName/1.0".
   */
  private static final String APPLICATION_NAME = "ServiceCalendar";

  /** E-mail address of the service account. */
  private static final String SERVICE_ACCOUNT_EMAIL = "135965950222_test@developer.gserviceaccount.com";

  /** Global instance of the HTTP transport. */
  private static HttpTransport httpTransport;

  /** Global instance of the JSON factory. */
  private static final JsonFactory JSON_FACTORY = JacksonFactory.getDefaultInstance();


  public  Calendar configure() {
    try {
      try {
        httpTransport = new NetHttpTransport();
        // check for valid setup
        if (SERVICE_ACCOUNT_EMAIL.startsWith("Enter ")) {
          System.err.println(SERVICE_ACCOUNT_EMAIL);
          System.exit(1);
        }
        URL loc = this.getClass().getResource("/ServiceApp-13c8dce63281.p12"); 
        String path = loc.getPath(); 
        File file = new File(path);
        String p12Content = Files.readFirstLine(file, Charset.defaultCharset());
        if (p12Content.startsWith("Please")) {
          System.err.println(p12Content);
          System.exit(1);
        }
        // service account credential (uncomment setServiceAccountUser for domain-wide delegation)
        GoogleCredential credential = new GoogleCredential.Builder()
            .setTransport(httpTransport)
            .setJsonFactory(JSON_FACTORY)
            .setServiceAccountId(SERVICE_ACCOUNT_EMAIL)
            .setServiceAccountScopes(Collections.singleton(CalendarScopes.CALENDAR))
            .setServiceAccountPrivateKeyFromP12File(file)
            .build();
     Calendar   client = new com.google.api.services.calendar.Calendar.Builder(
             httpTransport, JSON_FACTORY, credential)
                .setApplicationName(APPLICATION_NAME).build();
     System.out.println("Client : "+client);
     return client;

      } catch (IOException e) {
        System.err.println(e.getMessage());
      }
    } catch (Throwable t) {
      t.printStackTrace();
    }
    System.exit(1);
    return null;
  }

}  

Test Class is :

import java.util.ArrayList;
import java.util.Date;

import com.google.api.client.util.DateTime;
import com.google.api.services.calendar.Calendar;
import com.google.api.services.calendar.model.Event;
import com.google.api.services.calendar.model.EventAttendee;
import com.google.api.services.calendar.model.EventDateTime;
public class CalenderEventTest {

    public static void main(String[] args) throws IOException {
        // TODO Auto-generated method stub
        Event event = new Event();
        Calendar service =null;

        event.setSummary("Calendar Testing");
        event.setLocation("US");
        event.setDescription("Desired description");

        ArrayList<EventAttendee> attendees = new ArrayList<EventAttendee>();
        attendees.add(new EventAttendee().setEmail("tester@gmail.com"));
        // ...
        event.setAttendees(attendees);


        // set the number of days
        java.util.Calendar startCal = java.util.Calendar.getInstance();
        startCal.set(java.util.Calendar.MONTH, 11);
        startCal.set(java.util.Calendar.DATE, 26);
        startCal.set(java.util.Calendar.HOUR_OF_DAY, 9);
        startCal.set(java.util.Calendar.MINUTE, 0);
        Date startDate = startCal.getTime();

        java.util.Calendar endCal = java.util.Calendar.getInstance();
        endCal.set(java.util.Calendar.MONTH, 11);
        endCal.set(java.util.Calendar.DATE, 26);
        endCal.set(java.util.Calendar.HOUR_OF_DAY, 18);
        endCal.set(java.util.Calendar.MINUTE, 0);
        Date endDate = endCal.getTime();


        DateTime start = new DateTime(startDate);
        event.setStart(new EventDateTime().setDateTime(start));
        DateTime end = new DateTime(endDate);
        event.setEnd(new EventDateTime().setDateTime(end));

        service = new CalendarService().configure();
        Event createdEvent = service.events().insert("primary", event).execute();

        System.out.println("Data is :"+createdEvent.getId()); 
    }
}  

Maven dependency is :

<properties>
        <google.version>1.19.0</google.version>
    </properties>  
<dependencies>
        <dependency>
            <groupId>com.google.api-client</groupId>
            <artifactId>google-api-client</artifactId>
            <version>1.19.0</version>
        </dependency>
        <dependency>
            <groupId>com.google.apis</groupId>
            <artifactId>google-api-services-calendar</artifactId>
            <version>v3-rev96-1.19.0</version>
        </dependency>
        <dependency>
            <groupId>com.google.oauth-client</groupId>
            <artifactId>google-oauth-client</artifactId>
            <version>1.19.0</version>
        </dependency>
        <dependency>
            <groupId>com.google.http-client</groupId>
            <artifactId>google-http-client-jackson</artifactId>
            <version>1.19.0</version>
        </dependency>

        <dependency>
            <groupId>com.google.http-client</groupId>
            <artifactId>google-http-client-jackson2</artifactId>
            <version>1.19.0</version>
        </dependency>
    </dependencies>  

And one should put the ServiceApp-13c8dce63281.p12 file in resources folder of maven.
It will work undoubtedly.
Hope it helps someone in need.

Answer 2

First go to Google developer console, create a project, get a service account and private key file. Share the calendar to the service account email.

HttpTransport TRANSPORT = GoogleNetHttpTransport.newTrustedTransport();
JsonFactory JSON_FACTORY = new JacksonFactory();
GoogleCredential credential = new GoogleCredential.Builder().setTransport(TRANSPORT)
            .setJsonFactory(JSON_FACTORY)
            .setServiceAccountId(SERVICE_ACCOUNT)
            .setServiceAccountScopes(Collections.singleton(CalendarScopes.CALENDAR))
            .setServiceAccountPrivateKeyFromP12File(new File(key.p12))
            .build();

    service = new Calendar.Builder(TRANSPORT, JSON_FACTORY, credential)
        .build();