通过SMTP发送电子邮件时出错 [英] Error in sending email through SMTP

问题描述

我试图通过Java代码使用Gmail作为SMTP发送电子邮件。但是得到如下的异常。你能让我知道为什么找不到gmail主机。我正在办公室网络工作，不知道一些防火墙是否阻止它发送。如果是，是什么出路？

I'm trying to send an email through Java Code using gmail as the SMTP. But getting an exception as below. Can you pls let me know why is it not able to find the gmail host. I'm working in office network, not sure if some firewall is stopping it from sending. If yes, what is the way out ?

Exception in thread "main" com.sun.mail.util.MailConnectException: Couldn't connect to host, port: smtp.gmail.com, 586; timeout -1;
  nested exception is:
    java.net.UnknownHostException: smtp.gmail.com
    at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:2053)
    at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:697)
    at javax.mail.Service.connect(Service.java:364)
    at javax.mail.Service.connect(Service.java:245)
    at mail.JavaEmail.sendEmail(JavaEmail.java:72)
    at mail.JavaEmail.main(JavaEmail.java:22)
Caused by: java.net.UnknownHostException: smtp.gmail.com

Java源代码：

package mail;

import java.util.Properties;

import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.AddressException;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;

public class JavaEmail
{
    Session mailSession;

    public static void main(String args[]) throws AddressException,    MessagingException
    {
        JavaEmail javaEmail = new JavaEmail();
        javaEmail.setMailServerProperties();
        javaEmail.draftEmailMessage();
        javaEmail.sendEmail();
    }

    private void setMailServerProperties()
    {
        Properties emailProperties = System.getProperties();
        emailProperties.put("mail.smtp.port", "586");
        emailProperties.put("mail.smtp.auth", "true");
        emailProperties.put("mail.smtp.starttls.enable", "true");
        mailSession = Session.getDefaultInstance(emailProperties, null);
    }

    private MimeMessage draftEmailMessage() throws AddressException, MessagingException
    {
        String[] toEmails = { "[e-mail]" };
        String emailSubject = "Test email subject";
        String emailBody = "This is an email sent by JAVA Code";
        MimeMessage emailMessage = new MimeMessage(mailSession);
        /**
         * Set the mail recipients
         * */
        for (int i = 0; i < toEmails.length; i++)
        {
            emailMessage.addRecipient(Message.RecipientType.TO, new InternetAddress(toEmails[i]));
        }
        emailMessage.setSubject(emailSubject);
        /**
         * If sending HTML mail
         * */
        emailMessage.setContent(emailBody, "text/html");
        /**
         * If sending only text mail
         * */
        //emailMessage.setText(emailBody);// for a text email
        return emailMessage;
    }

    private void sendEmail() throws AddressException, MessagingException
    {
        /**
         * Sender's credentials
         * */
    String fromUser = "[e-mail]";
        String fromUserEmailPassword = "*****";

        String emailHost = "smtp.gmail.com";
        Transport transport = mailSession.getTransport("smtp");
        transport.connect(emailHost, fromUser, fromUserEmailPassword);
        /**
         * Draft the message
         * */
        MimeMessage emailMessage = draftEmailMessage();
        /**
         * Send the mail
         * */
        transport.sendMessage(emailMessage, emailMessage.getAllRecipients());
        transport.close();
        System.out.println("Email sent successfully.");
    }
}

推荐答案

你'连接到错误的端口。 Google的SMTP服务器为 587 。您可以在此处查看有关此处的更多信息： http://email.about.com/ od / accessgmail / f / Gmail_SMTP_Settings.htm

You're connecting to the wrong port. Google's SMTP server for TLS is 587. You can see more information on this here: http://email.about.com/od/accessinggmail/f/Gmail_SMTP_Settings.htm

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