这个实例实现了构建邮件服务器、简单的E-mail发送、发送附件、带身份验证的E-mail发送、跨代理的E-mail发送、接收E-mail、在Applet中收取E-mail、E-mail口令验证功能-achieve this example of building a mail server, a simple E-mail sent, send attachments, with identification of the E-mail sent, the inter-agency E-mail