发送邮件时出错 - ConnectException

Question

我使用以下 Java 代码发送电子邮件。

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

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

      String to = "abcd@gmail.com";
      String from = "web@gmail.com";
      String host = "localhost";
      Properties properties = System.getProperties();
      properties.setProperty("smtp.gmail.com", 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("This is the Subject Line!");
         message.setText("This is actual message");
         Transport.send(message);
         System.out.println("Sent message successfully....");
      }catch (MessagingException mex) {
         mex.printStackTrace();
      }
   }
}

当我运行该文件时，我收到以下错误：

javax.mail.MessagingException: Could not connect to SMTP host: localhost, port: 25;
nested exception is:
java.net.ConnectException: Connection refused: connect
at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:1282)
at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:370)

Caused by: java.net.ConnectException: Connection refused: connect
    at java.net.DualStackPlainSocketImpl.connect0(Native Method)
    at java.net.DualStackPlainSocketImpl.socketConnect(Unknown Source)

如果有人可以帮助我，我将不胜感激。

ConnectException如何解决？

Answer 1

我可以看到您正在尝试使用Gmail 作为您的 SMTP 服务器。此行不正确：

properties.setProperty("smtp.gmail.com", host);

您使用主机名作为属性名，这是不正确的。因为您没有设置mail.smtp.host 属性JavaMail 尝试连接到'localhost'。请改为设置以下属性：

properties.put("mail.smtp.starttls.enable", "true"); 
properties.put("mail.smtp.host", "smtp.gmail.com");
properties.put("mail.smtp.user", "username"); // User name
properties.put("mail.smtp.password", "password"); // password
properties.put("mail.smtp.port", "587");
properties.put("mail.smtp.auth", "true");

Answer 2

将主机名更改为：smtp.gmail.com

String host = "localhost";

将其更改为：

String host = "smtp.gmail.com"

Answer 3

你必须尝试这样的事情

String host = "smtp.gmail.com";
String from = "user name";
Properties props = System.getProperties();
props.put("mail.smtp.host", host);
props.put("mail.smtp.user", from);
props.put("mail.smtp.password", "asdfgh");
props.put("mail.smtp.port", "587"); // 587 is the port number of yahoo mail
props.put("mail.smtp.auth", "true");

Session session = Session.getDefaultInstance(props, null);
MimeMessage message = new MimeMessage(session);
message.setFrom(new InternetAddress(from));

InternetAddress[] to_address = new InternetAddress[to.length];
int i = 0;
// To get the array of addresses
while (to[i] != null) {
    to_address[i] = new InternetAddress(to[i]);
    i++;
}
System.out.println(Message.RecipientType.TO);
i = 0;
while (to_address[i] != null) {

    message.addRecipient(Message.RecipientType.TO, to_address[i]);
    i++;
}
message.setSubject("sending in a group");
message.setText("Welcome to JavaMail");
// alternately, to send HTML mail:
// message.setContent("<p>Welcome to JavaMail</p>", "text/html");
Transport transport = session.getTransport("smtp");
transport.connect("smtp.mail.yahoo.co.in", "user name", "asdfgh");
transport.sendMessage(message, message.getAllRecipients());
transport.close();

现在您正在尝试连接到 localhost

礼貌this answer

Answer 4

尝试将其添加到您的属性中：

private static final String SMTP_HOST = "smtp.gmail.com"; //Use Gmail's SMTP Host.
private static final String SMTP_PORT = ""; //Use Gmail's Port Number for SMTP.
properties.setProperty("mail.smtp.host", SMTP_HOST);
properties.setProperty("mail.smtp.port", SMTP_PORT);

Answer 5

假设我的

电子邮件：liferayasif@gmail.com

密码：密码

public Session getSession() {
        
        Properties props = new Properties();
    
        props.put("mail.smtp.starttls.enable", "true"); 
        
        props.put("mail.smtp.host", "smtp.gmail.com");
        props.put("mail.smtp.user", "liferayasif"); // User name
        props.put("mail.smtp.password", "password"); // password
        props.put("mail.smtp.port", "587");
        props.put("mail.smtp.auth", "true");
        
        props.put("mail.session.mail.pop3.host", "pop.gmail.com");

        props.put("mail.session.mail.pop3.password", "password");

        props.put("mail.session.mail.pop3.port", "110");

        props.put(" mail.session.mail.pop3.user", "USER");

        props.put("mail.session.mail.imap.host", "imap.gmail.com");

        props.put("mail.session.mail.imap.port", "993");

        props.put("mail.session.mail.store.protocol", "imap");

        props.put("mail.session.mail.transport.protocol", "smtp");

        props.put("mail.session.mail.smtp.host", "smtp.gmail.com");

        props.put("mail.session.mail.smtp.password", "password");

        props.put("mail.session.mail.smtp.user", "liferayasif@gmail.com");

        props.put("mail.session.mail.smtp.port", "465");

        props.put("mail.session.mail.smtp.auth", "true");

        props.put("mail.session.mail.smtp.starttls.enable", "true");

        props.put("mail.session.mail.smtp.socketFactory.class", "javax.net.ssl.SSLSocketFactory");
              
        Session session = Session.getInstance(props,
         new javax.mail.Authenticator() {
            protected PasswordAuthentication getPasswordAuthentication() {
               return new PasswordAuthentication("liferayasif", "password");
            }
         });
      
      return session;
    }