为了避免25端口被黑,云服务器都会将25端口禁用,因此,我们使用465端口连接邮箱服务器,这里需要注意,在服务端要开启邮箱ssl配置,不开启一般会有有如下错误:org.springframework.mail.MailSendException: Mail server connection failed; nested exception is javax.mail.MessagingException: Could not connect to SMTP host: smtp.qq.com,