封装得很好的邮件(E-mail/Email)发送程序，实现了SMTP协议。如果你想做类似于outlook/foxmail这样的邮件客户端，可以考虑参考。-Packaging very good mail (E-mail/Email) Send procedures, the SMTP protocol. If you want similar to the outlook / foxmail the mail client, reference can be considered.