线程“主”中的异常java.lang.RuntimeException：javax.mail.MessagingException：无法连接到SMTP主机：smtp.gmail.com，端口：578；

Question

我是Java新手。 我想构建一个将电子邮件发送给我的客户的应用程序。 我搜索了stackoverflow，但没有得到任何想要的解决方案。 我在某个地方看到这可能是防火墙的问题，但没有得到解决它的解决方案。 我正在使用Ubuntu 14.10
//这是我的代码。

public class sendMail {

    public void send(String from, String to, String subject, String body) {
        Properties props = new Properties();
        props.put("mail.smtp.host", "smtp.gmail.com");
        props.put("mail.smtp.socketFactory.port", "587");
        props.put("mail.smtp.socketFactory.class",
            "javax.net.ssl.SSLSocketFactory");
        props.put("mail.smtp.auth", "true");
        props.put("mail.smtp.port", "587");

        Session session = Session.getDefaultInstance(props,
            new javax.mail.Authenticator() {
                protected PasswordAuthentication getPasswordAuthentication() {
                    return new PasswordAuthentication("xxxxxxx@gmail.com","xxxxx");
            }
        });

        try {

            Message message = new MimeMessage(session);
            message.setFrom(new InternetAddress("xxxxxx@gmail.com"));
            message.setRecipients(Message.RecipientType.TO,
                InternetAddress.parse("xxxx@domain.com"));
            message.setSubject("Testing Subject");
            message.setText("Hello this is not spam," +
                "\n\n This is a JavaMail test...!");

            Transport.send(message);

            System.out.println("Done");

        } catch (MessagingException e) {
            throw new RuntimeException(e);
        }
    }  
}  

我的错误是：

Exception in thread "main" java.lang.RuntimeException: javax.mail.MessagingException: Could not connect to SMTP host: smtp.gmail.com, port: 587;
    nested exception is:
       java.net.ConnectException: Connection timed out
       at dbdemo.sendMail.send(sendMail.java:54)
       at dbdemo.DBDemo.main(DBDemo.java:62)
Caused by: javax.mail.MessagingException: Could not connect to SMTP host: smtp.gmail.com, port: 587;
    nested exception is:
       java.net.ConnectException: Connection timed out
       at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:1706)
       at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:525)
       at javax.mail.Service.connect(Service.java:313)
       at javax.mail.Service.connect(Service.java:172)
       at javax.mail.Service.connect(Service.java:121)
       at javax.mail.Transport.send0(Transport.java:190)
       at javax.mail.Transport.send(Transport.java:120)
       at dbdemo.sendMail.send(sendMail.java:49)
       ... 1 more
Caused by: java.net.ConnectException: Connection timed out
       at java.net.PlainSocketImpl.socketConnect(Native Method)
       at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:339)
       at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:200)
       at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:182)
       at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
       at java.net.Socket.connect(Socket.java:579)
       at java.net.Socket.connect(Socket.java:528)
       at com.sun.mail.util.SocketFetcher.createSocket(SocketFetcher.java:284)
       at com.sun.mail.util.SocketFetcher.getSocket(SocketFetcher.java:227)
       at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:1672)
       ... 8 more
Java Result: 1

任何帮助，将不胜感激。 请帮我。

Answer 1

丢弃那些不懂JavaMail的人剪切和粘贴的代码，并使用JavaMail FAQ中的代码连接到Gmail 。

如果对您不起作用，请遵循JavaMail FAQ中的调试提示 。

如果仍然无法解决问题，并且在JavaMail FAQ中找不到答案，请在此处发布JavaMail调试输出。

Answer 2

这段代码对我有用

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

public class Email {

private static String USER_NAME = "xxxx";  // GMail user name (just the part before "@gmail.com")
private static String PASSWORD = "xxxx"; // GMail password
private static String RECIPIENT = "xxx@gmail.com";

public static void main(String[] args) {
    String from = USER_NAME;
    String pass = PASSWORD;
    String[] to = { RECIPIENT }; // list of recipient email addresses
    String subject = "Java send mail example";
    String body = "Welcome to JavaMail!";

    sendFromGMail(from, pass, to, subject, body);
}

private static void sendFromGMail(String from, String pass, String[] to, String subject, String body) {
    Properties props = System.getProperties();
  String host = "smtp.gmail.com";
   // String host="localhost";
  // props.put("mail.smtp.ssl.trust", "smtp.gmail.com");
    props.put("mail.smtp.starttls.enable", "true");
   // props.put("mail.smtp.host", host);
   props.put("mail.smtp.ssl.trust", host);
    props.put("mail.smtp.user", from);
    props.put("mail.smtp.password", pass);
    props.put("mail.smtp.port", "587");//587
    props.put("mail.smtp.auth", "true");
   //System.out.println("success point 1");

    Session session = Session.getDefaultInstance(props);
    MimeMessage message = new MimeMessage(session);

    try {
         //System.out.println("success point 2");

        message.setFrom(new InternetAddress(from));
        InternetAddress[] toAddress = new InternetAddress[to.length];

        // To get the array of addresses
        for( int i = 0; i < to.length; i++ ) {
            toAddress[i] = new InternetAddress(to[i]);
        }

        for( int i = 0; i < toAddress.length; i++) {
            message.addRecipient(Message.RecipientType.TO, toAddress[i]);
        }

         //System.out.println("success point 3");

        message.setSubject(subject);
        message.setText(body);
        // System.out.println("success point 4");

        Transport transport = session.getTransport("smtp");
        // System.out.println("success point 5");

        transport.connect(host, from, pass);
        transport.sendMessage(message, message.getAllRecipients());
        transport.close();
        //System.out.println("success 6");
    }
    catch (AddressException ae) {
        ae.printStackTrace();
    }
    catch (MessagingException me) {
        me.printStackTrace();
    }
  }
}

我曾经使用过一些jar文件进行激活，java-mail-1.4.4，javamail-smtp-1.4.2，pop3，mail-6.0.0-sources

Answer 3

连接超时通常是由于

• 一种简单的防火墙，只吃掉数据包而没有告诉发件人诸如“没有路由到主机”之类的信息
• 网络配置错误或线路过载导致数据包丢失
• 太多请求使服务器超载

这是我如何在Ubuntu上关闭防火墙

如果这样不起作用，请尝试更改props.put("mail.smtp.port", "587"); 到props.put("mail.smtp.port", "465"); 或props.put("mail.smtp.port", "25");

---

建立连接后，一些其他信息（与超时无关）：

不要忘记再次检查您的登录凭据。 因为如果提供不正确，它们可能会导致Authentication Failed Exception