参照EmailServiceImpl里的实现，往自己的一个163邮箱发送500封邮件，结果好几次都是到了大概250封左右，后台抛异常

Caused by: javax.mail.MessagingException: Can't send command to SMTP host;
  nested exception is:
	java.net.SocketException: Connection closed by remote host
	at com.sun.mail.smtp.SMTPTransport.sendCommand(SMTPTransport.java:2306)
	at com.sun.mail.smtp.SMTPTransport.sendCommand(SMTPTransport.java:2293)
	at com.sun.mail.smtp.SMTPTransport.close(SMTPTransport.java:1333)
	at javax.mail.Transport.send0(Transport.java:257)
	at javax.mail.Transport.send(Transport.java:124)
	at org.apache.commons.mail.Email.sendMimeMessage(Email.java:1411)
	... 8 more

是不是163邮箱的防垃圾邮件的设置啊，连续接收到邮件，认为是垃圾邮件，关闭连接了？
还是本身代码的问题

    @Inject("refer:$ioc")
    protected Ioc ioc;

    public boolean send(String to, String subject, String html) {
        try {
            HtmlEmail email = ioc.get(HtmlEmail.class);
            email.setSubject(subject);
            email.setHtmlMsg(html);
            email.setCharset("utf-8");
            email.addTo(to);
            email.buildMimeMessage();
            email.sendMimeMessage();
            return true;
        } catch (Throwable e) {
            log.error("send email fail", e);
            return false;
        }
    }