连接POP3服务器；得到邮件对象数组；查看指定的邮件信息；删除邮件； 连接SMTP服务器，然后就是设置邮件的相关信息，最后是调用方法完成发邮件操作。-POP3 server connectivity receive e-mail object array view the designated e-mail information delete mail connecting SMTP server, and then is set up e-mail information, an