用HTTPClient访问exchange服务器报错，大家帮忙看下！
具体错误信息：
401 - 未授权: 由于凭据无效，访问被拒绝。
您无权使用所提供的凭据查看此目录或页面。
访问代码：
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;
