java - 通过 GMail 使用 SMTP 时如何修复 javax.mail.MessagingException？

Question

我无法执行可公开通过 Gmail 发送电子邮件的代码。我认为这可能是网络问题，因为我正在工作，尽管我可以通过 cmd 提示符 ping Gmail:ping smtp.gmail.com。

这是我正在使用的代码(来自 this page ):

import javax.mail.Authenticator;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;
import java.util.Properties;


class tester {
    public static void main(String args[]) {
        Properties props = new Properties();
        props.put("mail.smtp.host", "smtp.gmail.com");
        props.put("mail.stmp.user", "username of the sender");          
        //If you want you use TLS 
        props.put("mail.smtp.auth", "true");
        props.put("mail.smtp.starttls.enable", "true");
        props.put("mail.smtp.password", "password of the sender");
        // If you want to use SSL
        props.put("mail.smtp.socketFactory.port", "465");
        props.put("mail.smtp.socketFactory.class", "javax.net.ssl.SSLSocketFactory");
        props.put("mail.smtp.auth", "true");
        props.put("mail.smtp.port", "465");
        Session session = Session.getDefaultInstance(props, new Authenticator() {
            @Override
                protected PasswordAuthentication getPasswordAuthentication() {
                    String username = "username";
                    String password = "password";
                    return new PasswordAuthentication("username","password"); 
                }
            });
        String to = "me@gmail.com";
        String from = "from@gmail.com";
        String subject = "Testing...";
        MimeMessage msg = new MimeMessage(session);
        try {
            msg.setFrom(new InternetAddress(from));
            msg.setRecipient(MimeMessage.RecipientType.TO, new    InternetAddress(to));
            msg.setSubject(subject);
            msg.setText("JAVA is the BEST");
            Transport transport = session.getTransport("smtp");
            transport.send(msg);
            System.out.println("E-mail sent !");
        } catch(Exception exc) {
            System.out.println(exc);
        }
    }
}

我已将用户名和密码字段更改为正确的。有哪些因素可能会导致这种情况？我为此使用了自己的代码和许多其他公开可用的代码，但遇到了相同的错误。我也尝试通过端口 587 运行并收到相同的错误。

这是错误:

javax.mail.MessagingException: Could not connect to SMTP host: smtp.gmail.com, port: 465;
nested exception is: java.net.ConnectException: Connection refused: connect
    at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:1961)
    at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:654)
    at javax.mail.Service.connect(Service.java:317)
    at javax.mail.Service.connect(Service.java:176)
    at javax.mail.Service.connect(Service.java:125)
    at javax.mail.Transport.send0(Transport.java:194)
    at javax.mail.Transport.send(Transport.java:124)
    at GoogleMail.sendMail(GoogleMail.java:45)

Answer 1

我在 cmd 提示符下使用了 telnet smtp.gmail.com 465 和 telnet smtp.gmail.com 587 命令，两者都可以无法连接。我认为它与我所连接的网络相关联。我无法提供除此之外的任何信息，如果我发现更多信息，我将进行更新。