Java 电子邮件程序不发送电子邮件

Question

我正在为我的类之一做一个期末项目，这个程序是为了发送电子邮件到代码中的地址。我知道大部分代码是如何工作的，只是无法理解密码身份验证以及如何连接到 SMTP 服务器和使用特定端口。代码的问题是它在运行时不发送电子邮件，并且不给出任何错误消息。任何帮助将非常感激。这是代码。

    package application;

import java.util.Properties;

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


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

  String host="smtp.gmail.com";  
  final String user="myemail@gmail.com";
  final String password="password";

  String to="targetemail.com";

    //imported code
   Properties props = new Properties(); 
   props.put("mail.smtp.socketfactory.port",  "465");
   props.put("mail.smtp.port",  "465");
   props.put("mail.smtp.host",host);  
   props.put("mail.smtp.auth", "true");  

   Session session = Session.getDefaultInstance(props,  
    new javax.mail.Authenticator() {  
      protected PasswordAuthentication getPasswordAuthentication() {  
    return new PasswordAuthentication(user,password);  
      }  
    });  

 //imported code
        try {  
         MimeMessage message = new MimeMessage(session);  
         message.setFrom(new InternetAddress(user));  
         message.addRecipient(Message.RecipientType.TO, new InternetAddress(to));  
         message.setSubject("Dwight from the future");  
         message.setText("At 8:00, someone poisons the coffee. Do NOT drink 
    it.");  


         Transport.send(message);  

         System.out.println("message sent!");  

         } 
        catch (MessagingException mex) 
        {
            System.out.println("Error: unable to send message....");
            mex.printStackTrace();
        }
     }  
   }

Answer 1

我认为端口值应该如下所示

 props.put("mail.smtp.port", "587");

示例配置

 props.put("mail.smtp.host", "smtp.gmail.com"); 
 props.put("mail.smtp.auth", "true"); 
 props.put("mail.smtp.port", "587"); 
 props.put("mail.smtp.starttls.enable", "true"); 
 props.put("mail.smtp.ssl.trust", "*");

Answer 2

请尝试下面的代码（修改端口值）。

import java.util.Properties;

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


public class Main {

    public static void main(String[] args) {

        String host="smtp.gmail.com";
        final String user="email@gmail.com";
        final String password="*********";

        String to="username@gmail.com";

        //imported code
        Properties props = new Properties();
        props.put("mail.smtp.starttls.enable", "true");
        props.put("mail.smtp.host", host);
        props.put("mail.smtp.user", user);
        props.put("mail.smtp.password", password);
        props.put("mail.smtp.port", "587");
        props.put("mail.smtp.auth", "true");


        Session session = Session.getDefaultInstance(props,
                new javax.mail.Authenticator() {
                    protected PasswordAuthentication getPasswordAuthentication() {
                        return new PasswordAuthentication(user,password);
                    }
                });

        //imported code
        try {
            MimeMessage message = new MimeMessage(session);
            message.setFrom(new InternetAddress(user));
            message.addRecipient(Message.RecipientType.TO, new InternetAddress(to));
            message.setSubject("Dwight from the future");
            message.setText("At 8:00, someone poisons the coffee. Do NOT drinkit.");


                    Transport.send(message);

            System.out.println("message sent!");

        }
        catch (MessagingException mex)
        {
            System.out.println("Error: unable to send message....");
            mex.printStackTrace();
        }

    }
}

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