java.net.SocketException：读取邮件时连接重置

Question

javax.mail.MessagingException: Connection reset; nested exception is: java.net.SocketException: Connection reset

I have a service to read mails from outlook. Receiving the above error randomly. What would be the root cause of this issue. Using JAVA 8 and javax.mail-1.6.2 to read mails.

Below is my mail settings

Properties props = new Properties();
props.put("mail.transport.protocol", "smtp");
props.put("mail.smtp.host", "outlook.office365.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");
props.put("mail.smtp.starttls.enable", "true");

Answer 1

The problem is more likely to be a network issue than an issue with your application. It might be worth having a look here to see if any of those probable causes are likely or possible in your circumstance. Having had a similar issue with outlook previously with no root cause established, mitigation is also an option. Below shows a basic retry mechanism which, in practical terms, eliminated the issue.

            // send email with try-catch loop 
            int count = 0;
            int maxTries = 5;
            while(true) {
                try {
                    // get and set your protocols
                    mailSender.send(message);
                    break;
                } catch (Exception e) {
                    if (++count == maxTries) {
                        // Give up and throw the error
                        throw e;
                    }
                }
            }