为什么javamail会因身份验证异常而失败？

我已经提供了所有必要的投入。但它仍然失败了

package com.bcs;
import java.util.Properties;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;

public class SendMailTLS {

    public static void main(String[] args) {
        String host = "smtp.gmail.com";
        int port = 587;
        String username = "foo@gmail.com";
        String password = "bar";

        Properties props = new Properties();
        props.put("mail.smtp.auth", "true");
        props.put("mail.smtp.starttls.enable", "true");

        Session session = Session.getInstance(props);

        try {
            Message message = new MimeMessage(session);
            message.setFrom(new InternetAddress(""));
            message.setRecipients(Message.RecipientType.TO,
                InternetAddress.parse(""));
            message.setSubject("Testing Subject");
            message.setText("Dear Mail Crawler," +
                    "\n\n No spam to my email, please!");

            Transport transport = session.getTransport("smtp");
            transport.connect(host, port, username, password);
            Transport.send(message);

            System.out.println("Done");

        } catch (MessagingException e) {
            throw new RuntimeException(e);
        }
    }
}

我是java mail的新手。如有任何帮助，将不胜感激。

这可能会有帮助：

我认为您应该设置以下属性：

Exception in thread "main" java.lang.RuntimeException: javax.mail.AuthenticationFailedException: failed to connect, no password specified?
    at com.bcs.SendMailTLS.main(SendMailTLS.java:43)
Caused by: javax.mail.AuthenticationFailedException: failed to connect, no password specified?
    at javax.mail.Service.connect(Service.java:329)
    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 com.bcs.SendMailTLS.main(SendMailTLS.java:38)

---

端口为

465

这需要通过

smtps

传输进行连接，而不是通过

smtp

。并且OP具有用于

smtp

/

STARTTLS

的正确端口。这有用吗？

'mail.smtp.auth': 'true',
'mail.smtp.socketFactory.port': '465',
'mail.smtp.socketFactory.class': 'javax.net.ssl.SSLSocketFactory',
'mail.smtp.socketFactory.fallback': 'false'