Java Mail API-无法发送电子邮件

Question

I am trying to send an email using the Java Mail API like this:

public static void sendEmail(String to, String from, String msg) {
    String host = "localhost";
    Properties properties = System.getProperties();
    properties.setProperty("mail.smtp.host", host);
    Session session = Session.getDefaultInstance(properties);
    try {
        MimeMessage message = new MimeMessage(session);
        message.setFrom(new InternetAddress(from));
        message.addRecipient(Message.RecipientType.TO, new InternetAddress(to));
        message.setSubject("Subject");

        message.setText(msg);

        Transport.send(message);
    } catch (MessagingException mex) {
        mex.printStackTrace();
    }
}

but I am getting the following exception:

Answer 1

Remember to check that you have a SMTP server on some_host:25. You never send things directly but through a mail server, who keeps a queue and relays to the receiving mail server (eg gmail, hotmail and so on)

You can use Fake Sendmail or sendmail itself if you're on unix-like terminal

Answer 2

I've copied that from my project:

Properties properties = new Properties();
properties.putAll(propertyLoader.getAllProperties());
String senderEmail = properties.getProperty("mail.user");
String senderPswd = properties.getProperty("mail.password");

Authenticator auth = new Authenticator() {
  @Override
  protected PasswordAuthentication getPasswordAuthentication() {
    return new PasswordAuthentication(senderEmail, senderPswd);
  }
};

Session session = Session.getInstance(properties, auth);
MimeMessage mailMessage = new MimeMessage(session);
mailMessage.setSentDate(dateNow);
Address recipientAddress = new InternetAddress("your_recipient@gmail.com");
mailMessage.setRecipient(Message.RecipientType.TO, recipientAddress);
mailMessage.setSubject("message subject", "UTF-8");
Address senderAddress = new InternetAddress(senderEmail);
mailMessage.setSender(senderAddress);
mailMessage.setContent("here goes message text", "text/html; charset=utf-8");

Transport.send(mailMessage);

And your *.properties file should be like

mail.transport.protocol = smtp
mail.host = smtp.gmail.com
mail.port = 587
mail.port.tls = 587
mail.port.ssl = 465
mail.user = email@gmail.com
mail.password = password
mail.defaultEncoding = UTF-8
mail.smtp.starttls.enable= true
mail.smtp.auth = true

• Here I use google SMTP server, so for using that one you should have a mailbox in gmail