单击JButton时发送电子邮件？

Question

Someone please please be thorough and help me with this, I've been at this forever now. I'm somewhat new to programming and I've never set up a server or anything before. I get this error trying to run my program. " java.net.ConnectException: Connection refused: connect " and " javax.mail.MessagingException: Could not connect to SMTP host: localhost, port: 25; "

Here's my code :

private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
if (jButton1.isEnabled());
Properties sessionProperties = System.getProperties();
String to = "bleh@gmail.com";
    String from = "bleh@gmail.com"; 
    String host = "localhost"; 
    Properties properties = System.getProperties();
    properties.setProperty("mail.smtp.host", host);
    Session session = Session.getDefaultInstance(properties);

    try{
     // Create a default MimeMessage object.
     MimeMessage message = new MimeMessage(session);

     // Set From: header field of the header.
     message.setFrom(new InternetAddress(from));

     // Set To: header field of the header.
     message.addRecipient(Message.RecipientType.TO,
                              new InternetAddress(to));

     // Set Subject: header field
     message.setSubject("Infomation");

     // Now set the actual message
     message.setText("Hello!");

     // Send message
     Transport.send(message);

    }catch (MessagingException mex) {
     mex.printStackTrace();

Answer 1

It looks like your code came from http://www.tutorialspoint.com/java/java_sending_email.htm If so, I'd like to direct you to the sentence in the tut

Here it is assumed that your localhost is connected to the internet and capable enough
to send an email.

By capable, it means that you have an SMTP server running on localhost; the reason why you got the exception was because Transport attempted to use an SMTP server on localhost:25 to send the mail.

Your options are then to either run an SMTP server locally (a real pain) or to use a third-party SMTP (GMail, Amazon SES, etc.) service to send the mail.