通过HttpClient进行NTLM身份验证java

Question

我的问题是我正在尝试使用爬虫进入scopus，但它需要我的爬虫通过我的学校代理服务器进入该网站。我尝试过身份验证，但会继续以401状态回复。

public void testConnection() throws ClientProtocolException, IOException {
    DefaultHttpClient httpclient = new DefaultHttpClient();
    List<String> authpref = new ArrayList<String>();
    authpref.add(AuthPolicy.NTLM);
    httpclient.getParams().setParameter(AuthPNames.TARGET_AUTH_PREF, authpref);
    NTCredentials creds = new NTCredentials("username","password","ezlibproxy1.ntu.edu.sg","ntu.edu.sg");//this is correct
    httpclient.getCredentialsProvider().setCredentials(AuthScope.ANY, creds);

    HttpHost target = new HttpHost("ezlibproxy1.ntu.edu.sg", 443, "https");//this is correct

    // Make sure the same context is used to execute logically related requests
    HttpContext localContext = new BasicHttpContext();

    // Execute a cheap method first. This will trigger NTLM authentication
    HttpGet httpget = new HttpGet("http://www-scopus-com.ezlibproxy1.ntu.edu.sg/authid/detail.url?authorId=14831850700");
    HttpResponse response = httpclient.execute(target, httpget, localContext);
    HttpEntity entity = response.getEntity();
    System.out.println(EntityUtils.toString(entity));

    int statusCode = response.getStatusLine().getStatusCode();
    System.out.println("Status Code:" + statusCode);
}

状态代码响应为401 (unauthorised)。 有什么建议吗？