使用Java发送邮件时出错

Question

我的代码是:

// File Name SendEmail.java

import java.util.*;
import javax.mail.*;
import javax.mail.internet.*;
import javax.activation.*;

public class SendEmail
{
   public static void main(String [] args)
   {

      // Recipient's email ID needs to be mentioned.
      String to = "toEmail@gmail.com";

      // Sender's email ID needs to be mentioned
      String from = "fromEmail@gmail.com";

      // Assuming you are sending email from localhost
      String host = "localhost";

      // Get system properties
      Properties properties = System.getProperties();

      // Setup mail server
      properties.setProperty("mail.smtp.host", host);

      // Get the default Session object.
      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("This is the Subject Line!");

         // Now set the actual message
         message.setText("This is actual message");

         // Send message
         Transport.send(message);
         System.out.println("Sent message successfully....");
      }catch (MessagingException mex) {
         mex.printStackTrace();
      }
   }
}

我的节目昨晚工作正常; 我可以从任何地址向任何其他地址发送电子邮件,但现在出现此错误:

javax.mail.SendFailedException: Sending failed;
  nested exception is:
    class javax.mail.MessagingException: Could not connect to SMTP host: localhost, port: 25;
  nested exception is:
    java.net.ConnectException: Connection refused
    at javax.mail.Transport.send0(Transport.java:218)
    at javax.mail.Transport.send(Transport.java:80)
    at SendEmail.main(SendEmail.java:49)

第49行是:

Transport.send(message);

任何人都可以帮我解决这个错误吗？

我的操作系统是:Linux,Fedora 16 -kernel:3.3.7

Answer 1

无法连接到SMTP主机:localhost,port:25;

SMTP必须不在您的系统上运行或作为用户禁用.请咨询系统管理员并为您启用它.

要检查SMTP是否在Linux系统上运行,请尝试以下命令:

1. 要简单验证Sendmail是否正在运行,请尝试: netstat -an | grep 25
2. 使用telnet连接到smtp服务器的端口25:telnet <yourhost-or-ipnumber> 25
   a.连接到localhost ...无法打开与主机的连接,在端口25上:连接失败.
   湾 如果您或您的IP被阻止,您会看到如下错误消息:
   220-localhost ESMTP Exim 4.63#1 Fri,01 Jun 2012 19:35:30 +0530
   220 - 我们不授权使用此系统进行传输未经请求的和/或批量电子邮件.
3. echo -e "quit" | nc localhost 25
   localhost.localdomain [127.0.0.1] 25(？):连接被拒绝
4. 邮件在shell提示符下.
5. 而且,可能更多......

您应该检查sendmail守护程序是否已启动且始终可用.

如果您可以访问任何其他SMTP服务器,请尝试使用其SMTP主机名发送邮件,以检查您的代码段是否正常工作.
示例:String host = "smtp.gmail.com";