用HTTPClient访问exchange服务器报错，大家帮忙看下！该怎么处理

Protocol myHTTPS = new Protocol("https",                    new MySecureProtocolSocketFactory(), 443);            Protocol.registerProtocol("https", myHTTPS);            // 设置连接参数            HttpClient httpClient = new HttpClient();            httpClient.getParams().setParameter(                    HttpMethodParams.HTTP_CONTENT_CHARSET, "gbk");            PostMethod postMethod = new PostMethod(mailServer                    + "/owa/auth/owaauth.dll");            postMethod.setRequestHeader("Content-Type",                    "application/x-www-form-urlencoded");            NameValuePair destination = new NameValuePair("destination",                    mailServer + "/owa/");            NameValuePair flag = new NameValuePair("flag", "0");            NameValuePair forcedownlevel = new NameValuePair("forcedownlevel",                    "0");            NameValuePair trusted = new NameValuePair("trusted", "0");            NameValuePair username = new NameValuePair("username", user);            NameValuePair password = new NameValuePair("password", pw);            NameValuePair[] FieldArr = new NameValuePair[] { destination, flag,                    forcedownlevel, trusted, username, password };            postMethod.addParameters(FieldArr);            // 取邮件数            int statusCode = httpClient.executeMethod(postMethod);            GetMethod redirect = new GetMethod(mailServer + "/owa/");            redirect.getParams().setParameter(                    HttpMethodParams.HTTP_CONTENT_CHARSET, "gbk");            httpClient.executeMethod(redirect);            String str = redirect.getResponseBodyAsString();            System.out.println(str);            logger.debug(str);            int start = str.indexOf("</a><span class=\"unrd\">");            int end = str.indexOf(")</span></td></tr><tr>");            if (start != -1 && end != -1) {                start += "</a><span class=\"unrd\">".length();                rtnStr = str.substring(start + 1, end);            }            postMethod.releaseConnection();            httpClient = null;