java - 无法连接到 SMTP 主机 : smtp. gmail.com，端口 : 465, 响应:-1 为什么 465 不起作用

Question

我想创建电子邮件模板，因为我想附加 html 代码来创建模板，所以我尝试了下面的代码，在此 port 465号码不工作
任何人都可以帮助我吗？

package com.indoabus2.mail;

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 SendHTMLEmail {

public static void main(String[] args) {
      // Recipient's email ID needs to be mentioned.
      String to = "vpenchalaprasad2@gmail.com";

      // Sender's email ID needs to be mentioned
      String from = "vpenchalaprasad2@gmail.com";
      final String username = "vpenchalaprasad2";//change accordingly
      final String password = "100509732041";//change accordingly

      // Assuming you are sending email through relay.jangosmtp.net
      String host = "smtp.gmail.com";

      Properties props = new Properties();
      props.put("mail.smtp.auth", "true");
      props.put("mail.smtp.starttls.enable", "true");
      props.put("mail.smtp.host", host);
      props.put("mail.smtp.port", "465");

      // Get the Session object.
      Session session = Session.getInstance(props,
         new javax.mail.Authenticator() {
            protected PasswordAuthentication getPasswordAuthentication() {
               return new PasswordAuthentication(username, password);
            }
    });

      try {
            // Create a default MimeMessage object.
            Message message = new MimeMessage(session);

       // Set From: header field of the header.
       message.setFrom(new InternetAddress(from));

       // Set To: header field of the header.
       message.setRecipients(Message.RecipientType.TO,
              InternetAddress.parse(to));

       // Set Subject: header field
       message.setSubject("Testing Subject");

       // Send the actual HTML message, as big as you like
       message.setContent(
              "<h1>This is actual message embedded in HTML tags</h1>",
             "text/html");

       // Send message
       Transport.send(message);

       System.out.println("Sent message successfully....");

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



}

坚果代码没有被执行异常是

javax.mail.MessagingException: Could not connect to SMTP host: smtp.gmail.com, port: 465, response: -1

我无法追踪它为什么465不工作，什么是 response: -1任何人都可以建议我一个解决方案

Answer 1

Google SMTP 需要 SSL 而不是端口 465 的 STARTTLS。

只需删除:
props.put("mail.smtp.starttls.enable", "true");
并添加以使用 SSL:
props.put("mail.smtp.socketFactory.class", "javax.net.ssl.SSLSocketFactory");
或者您可以将端口更改为 587。

https://support.google.com/a/answer/176600?hl=en-EN