JavaMail 无法发送电子邮件

Question

我正在尝试用java编写一个发送电子邮件的应用程序，我在youtube上找到了一个教程并尝试遵循它。但是它仍然对我不起作用，这是我得到的错误

Exception in thread "main" javax.mail.MessagingException: Could not connect to SMTP host: localhost, port: 25, response: 421
at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:1949)
at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:654)
at javax.mail.Service.connect(Service.java:295)
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 libraryFineList.ParseRecords.main(ParseRecords.java:90)

我不知道出了什么问题，我在谷歌上找到的任何东西都没有帮助，

这是代码

    public static void main(String[] args) throws IOException, MessagingException {

    Properties props = new Properties();
    props.put("mail.smtp.host", "smtp.gmail.com");
    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 javax.mail.Authenticator(){
        protected  PasswordAuthentication getPasswordAuthentication(){
        return new PasswordAuthentication("<a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="a2d7d1c7d0e2c5cfc3cbce8cc1cdcf" rel="noreferrer noopener nofollow">[email protected]</a>", "pass");

        }
    }

            );

    try{
        Message message = new MimeMessage(session);
        message.setFrom(new InternetAddress("<a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="b2c7c1d7c0f2d5dfd3dbde9cd1dddf" rel="noreferrer noopener nofollow">[email protected]</a>"));
        message.addRecipient(Message.RecipientType.TO,
                   new InternetAddress("<a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="9ae3f9f2fbe8f4ffeee9f1fbe3fbdafdf7fbf3f6b4f9f5f7" rel="noreferrer noopener nofollow">[email protected]</a>", "Mr. User"));
        message.setSubject("Your Example.com account has been activated");
        message.setText("Worked");
  Transport.send(message);
    }catch(Exception e){
        e.printStackTrace();
    }

Answer 1

您遵循的教程充满了错误。首先修复这些common mistakes 。然后按照这些instructions for connecting to Gmail 。如果您仍然遇到问题，您可以在 JavaMail FAQ 中找到更多帮助。 。还有很多sample programs可用。