public static String sendEmail(String emailServer, String fromEmail, String password, String toEmail, String title, String content) {
    
    SimpleEmail email=new SimpleEmail();
    if (StrKit.notBlank(emailServer)) {
      email.setHostName(emailServer.trim());
    }
    else {
      // 默认使用本地 postfix 发送，这样就可以将postfix 的 mynetworks 配置为 127.0.0.1 或 127.0.0.0/8 了
      email.setHostName("127.0.0.1");
    }
      
    // 如果密码为空，则不进行认证
    if (StrKit.notBlank(password)) {
      email.setAuthentication(fromEmail, password);
    }
    
    email.setCharset("utf-8");
    try {
      email.setSslSmtpPort("465");
      email.setSSL(true);
      email.addTo(toEmail);
      email.setFrom(fromEmail);
      email.setSubject(title);
      email.setMsg(content);
      return email.send();
    } catch (EmailException e) {
      log.error(e.getMessage(), e);
      throw new RuntimeException(e);
    }
  }