使用Java使用Gmail API发送电子邮件时出错

Question

I'm trying to use the following code in order to sent an email using the new Gmail API. I collect it from different web sites and specially from Google examples. The code compiles successfully and after it gets authorized successfully, the code still running and running with out any results! It never stops! And of course it does not send any email at all! For that reason I need your opinion, help, and advice to fix this issue. I shall be happy to send you any further details or required Jar's. I think the error may be in the main class , and I tried to fix it but failed. Your help is really appreciated. Thanks

package test1;

import com.google.api.client.auth.oauth2.Credential;
import java.util.Arrays;
import java.util.Properties;
import javax.mail.MessagingException;
import javax.mail.Session;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;
import com.google.api.client.googleapis.auth.oauth2.GoogleAuthorizationCodeFlow;
import com.google.api.client.googleapis.auth.oauth2.GoogleClientSecrets;
import com.google.api.client.googleapis.auth.oauth2.GoogleCredential;
import com.google.api.client.googleapis.auth.oauth2.GoogleOAuthConstants;
import com.google.api.client.googleapis.auth.oauth2.GoogleTokenResponse;
import com.google.api.client.googleapis.javanet.GoogleNetHttpTransport;
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.jackson.JacksonFactory;
import com.google.api.client.repackaged.org.apache.commons.codec.binary.Base64;
import com.google.api.services.gmail.Gmail;
import com.google.api.services.gmail.model.Message;
import java.io.BufferedReader;
import java.io.ByteArrayOutputStream;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
public class Test1 {

    public static void main(String[] args) throws IOException, MessagingException ,FileNotFoundException //throws sendMail
    {
      //  System.out.println(getRequestUrl());
      //  BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
      //  emailCredentialSetup(br.readLine());
      //  sendMail("Alwa@gmail.com", "TEST1eee", "Hello");
      //  System.out.println("test");
      //  httpTransport = GoogleNetHttpTransport.newTrustedTransport();

      // initialize the data store factory
      // dataStoreFactory = new FileDataStoreFactory(DATA_STORE_DIR);

      // authorization
        System.out.println(getRequestUrl());
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        emailCredentialSetup(br.readLine());
        Test1 sendMail = new Test1();
        MimeMessage mail2;
        mail2 =  sendMail.createEmail("Alwa@gmail.com", "Alwa1@gmail.com", "yyyyyy", "kkkkkkkk");
        System.out.println("Obtener MIME: " + mail2);
        //sendMail(gmailClient, "from@gmail.com", mail2);
        sendMail("Alwa1@gmail.com", "TEST1eee", "Hello");

    }
    private static final String SCOPE = "https://www.googleapis.com/auth/gmail.modify";
    private static final String APP_NAME = "service_account";
    // Path to the client_secret.json file deloper Console
    private static final String CLIENT_SECRET_PATH = "./My Project-52.json";
    private static GoogleClientSecrets clientSecrets;
    private static GoogleAuthorizationCodeFlow flow;
    private static HttpTransport httpTransport;
    private static JsonFactory jsonFactory;
    private static Gmail service;

    public static String getRequestUrl() throws FileNotFoundException, IOException{
        httpTransport = new NetHttpTransport();
        jsonFactory = new JacksonFactory();

        clientSecrets = GoogleClientSecrets.load(jsonFactory, new FileReader(
                CLIENT_SECRET_PATH));

        // Allow user to authorize via url.
        flow = new GoogleAuthorizationCodeFlow.Builder(
                httpTransport, jsonFactory, clientSecrets, Arrays.asList(SCOPE))
        .setAccessType("online").setApprovalPrompt("auto").build();

        String url = flow.newAuthorizationUrl()
                .setRedirectUri(GoogleOAuthConstants.OOB_REDIRECT_URI).build();

        return url;
    }

    public static void sendMail(String to, String sub, String body) throws IOException, MessagingException {

        Message message = createMessageWithEmail(createEmail(to, "me", sub, body));
        message = service.users().messages().send("me", message).execute();

        System.out.println("Message id: " + message.getId());
        System.out.println(message.toPrettyString());
    }

    static void emailCredentialSetup(String code) throws IOException {
        // Generate Credential using retrieved code.
        GoogleTokenResponse response = flow.newTokenRequest(code)
                .setRedirectUri(GoogleOAuthConstants.OOB_REDIRECT_URI)
                .execute();
        GoogleCredential credential = new GoogleCredential()
                .setFromTokenResponse(response);

        // Create a new authorized Gmail API client
        service = new Gmail.Builder(httpTransport, jsonFactory,
                credential).setApplicationName(APP_NAME).build();
    }

    /**
       * Create a MimeMessage using the parameters provided.
       *
       * @param to Email address of the receiver.
       * @param from Email address of the sender, the mailbox account.
       * @param subject Subject of the email.
       * @param bodyText Body text of the email.
       * @return MimeMessage to be used to send email.
       * @throws MessagingException
     * @throws UnsupportedEncodingException 
       */
      private static MimeMessage createEmail(String to, String from, String subject,
          String bodyText) throws MessagingException, UnsupportedEncodingException {
        Properties props = new Properties();
        Session session = Session.getDefaultInstance(props, null);

        MimeMessage email = new MimeMessage(session);

        email.setFrom(new InternetAddress(from, "SPecial message"));
        email.addRecipient(javax.mail.Message.RecipientType.TO,
                           new InternetAddress(to));
        email.setSubject(subject);
        email.setText(bodyText);
        return email;
      }

      /**
       * Create a Message from an email
       *
       * @param email Email to be set to raw of message
       * @return Message containing base64 encoded email.
       * @throws IOException
       * @throws MessagingException
       */
      private static Message createMessageWithEmail(MimeMessage email)
          throws MessagingException, IOException {
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        email.writeTo(baos);
        String encodedEmail = Base64.encodeBase64URLSafeString(baos.toByteArray());
        Message message = new Message();
        message.setRaw(encodedEmail);
        return message;
      }   
}