android - 不正な構文リクエスト Android

Question

コードに表示されるリンクから情報を取得するログインアプリを作成しています。私の問題は、ログ ファイルに「400 Bad request.The request could not be received by server due to malformed syntax」というメッセージが表示されることです。

その上、そのリンクは、認証用の SHA1 とキー交換用の RSA を使用して RC4_128 を処理しますが、これらのプロトコルをコード内のどこに適用できるかはよくわかりません。

ご協力いただきありがとうございます！

これは私のコードです:

public class POPLogin extends Activity {

private EditText usr, pass;
private Button submitButton;
private CharSequence notify;
private String res, resp;
private final String link = "https://pop-portal.tut.fi/portal/page/portal/POP-portaali/20Opinnot/22Omat%20suoritukset";
private URL url;

public static boolean isNetworkAvailable(Context context) {
    return ((ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE)).getActiveNetworkInfo() != null;
}

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_poplogin);
    usr = ((EditText) findViewById(R.id.usernameField));            
    pass = ((EditText) findViewById(R.id.passwordField));           
    submitButton = (Button) findViewById(R.id.submitButton);        
    submitButton.getBackground().setColorFilter(new LightingColorFilter(0x00FFB90F, 0xFFAA0000));   

    /*
     * This method controls the login button so that the correct
     * information is sent to the server.
     */
    submitButton.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
            if(isNetworkAvailable(getApplicationContext())) {   // If there is an Internet connection available

                /*
                * A new thread is created from the main one 
                * to separate the login process (AsyncTask, https operations).
                */
                new Thread(new Runnable() {
                    public void run() {
                        try {
                            url = new URL(link);
                            HttpsURLConnection conn = (HttpsURLConnection) url.openConnection();

                            // Create the SSL Connection
                            SSLContext sc;
                            sc = SSLContext.getInstance("TLS");
                            sc.init(null, null, new java.security.SecureRandom());
                            conn.setSSLSocketFactory(sc.getSocketFactory());

                            // SSL Authentication
                            String userpass = usr.getText().toString() + ":" + pass.getText().toString();
                            String basicAuth = "Basic " + Base64.encodeToString(userpass.getBytes(), Base64.DEFAULT);
                            conn.setRequestProperty("Authorization", basicAuth);

                            Log.i("NOTIFICATION", "All SSL parameters set");

                            // Set timeout and method
                            conn.setReadTimeout(7000);
                            conn.setConnectTimeout(7000);
                            conn.setRequestMethod("POST");
                            conn.setDoInput(true);          // Flag indicating this connection is used for output (POST)
                            conn.connect();

                            Log.i("NOTIFICATION", "Connection request sent");

                            // Check HTTP Response Code
                            int status = conn.getResponseCode();
                            InputStream is;
                            if (status >= 400 ) {
                                is = conn.getErrorStream();
                            } else {
                                is = conn.getInputStream();
                            }

                            Log.i("NOTIFICATION", "HTTP Code Checked");

                            // Receives the answer
                            resp = null;
                            BufferedReader rd = new BufferedReader(new InputStreamReader(is));
                            while((res = rd.readLine()) != null) {
                                resp += res;
                            }
                            Log.i("NOTIFICATION", "Answer received");
                            Log.i("CODE", resp);

                        } catch (Exception e) {
                            e.printStackTrace();
                        }
                    }
                }).start();
            } else {
                notify = "Internet Connection not available";
            }

            if(notify != null) {
                Toast toast = Toast.makeText(getApplicationContext(), notify, Toast.LENGTH_SHORT);
                toast.show();
                notify = null;
            } 
        }
    });
}

public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.poplogin, menu);
    return true;
}

}