import com.google.api.client.googleapis.json.GoogleJsonResponseException;

import com.google.api.client.http.HttpRequestInitializer;

import com.google.api.client.http.javanet.NetHttpTransport;

import com.google.api.client.json.gson.GsonFactory;

import com.google.api.services.gmail.Gmail;

import com.google.api.services.gmail.GmailScopes;

import com.google.api.services.gmail.model.Draft;

import com.google.api.services.gmail.model.Message;

import com.google.auth.http.HttpCredentialsAdapter;

import com.google.auth.oauth2.GoogleCredentials;

import org.apache.commons.codec.binary.Base64;

import javax.activation.DataHandler;

import javax.activation.DataSource;

import javax.activation.FileDataSource;

import javax.mail.MessagingException;

import javax.mail.Multipart;

import javax.mail.Session;

import javax.mail.internet.InternetAddress;

import javax.mail.internet.MimeBodyPart;

import javax.mail.internet.MimeMessage;

import javax.mail.internet.MimeMultipart;

import java.io.ByteArrayOutputStream;

import java.io.File;

import java.io.IOException;

import java.util.Collections;

import java.util.Properties;

public class CreateDraftWithAttachment {

/**

public static Draft createDraftMessageWithAttachment(String fromEmailAddress,

String toEmailAddress,

File file)

throws MessagingException, IOException {

// Load pre-authorized user credentials from the environment.

// TODO(developer) - See https://developers.google.com/identity for

// guides on implementing OAuth2 for your application.

GoogleCredentials credentials = GoogleCredentials.getApplicationDefault().createScoped(Collections.singletonList(GmailScopes.GMAIL_COMPOSE));

HttpRequestInitializer requestInitializer = new HttpCredentialsAdapter(

credentials);

// Create the gmail API client

Gmail service = new Gmail.Builder(new NetHttpTransport(),

GsonFactory.getDefaultInstance(),

requestInitializer)

.setApplicationName("Gmail samples")

.build();

// Create the email content

String messageSubject = "Test message";

String bodyText = "lorem ipsum.";

// Encode as MIME message

Properties props = new Properties();

Session session = Session.getDefaultInstance(props, null);

MimeMessage email = new MimeMessage(session);

email.setFrom(new InternetAddress(fromEmailAddress));

email.addRecipient(javax.mail.Message.RecipientType.TO,

new InternetAddress(toEmailAddress));

email.setSubject(messageSubject);

MimeBodyPart mimeBodyPart = new MimeBodyPart();

mimeBodyPart.setContent(bodyText, "text/plain");

Multipart multipart = new MimeMultipart();

multipart.addBodyPart(mimeBodyPart);

mimeBodyPart = new MimeBodyPart();

DataSource source = new FileDataSource(file);

mimeBodyPart.setDataHandler(new DataHandler(source));

mimeBodyPart.setFileName(file.getName());

multipart.addBodyPart(mimeBodyPart);

email.setContent(multipart);

// Encode and wrap the MIME message into a gmail message

ByteArrayOutputStream buffer = new ByteArrayOutputStream();

email.writeTo(buffer);

byte[] rawMessageBytes = buffer.toByteArray();

String encodedEmail = Base64.encodeBase64URLSafeString(rawMessageBytes);

Message message = new Message();

message.setRaw(encodedEmail);

try {

// Create the draft message

Draft draft = new Draft();

draft.setMessage(message);

draft = service.users().drafts().create("me", draft).execute();

System.out.println("Draft id: " + draft.getId());

System.out.println(draft.toPrettyString());

return draft;

} catch (GoogleJsonResponseException e) {

// TODO(developer) - handle error appropriately

System.err.println("Unable to create draft: " + e.getDetails());

throw e;

}

}

}