文件下载程序中的基本访问身份验证问题

String authentication = this._login+":"+this._pass;
String encoding = Base64.encodeToString(authentication.getBytes(), 0);            

String fileName = "data.zip";
URL url = new URL("http://10.0.2.2/androidapp/data.zip"); 

HttpURLConnection ucon = (HttpURLConnection) url.openConnection();

ucon.setRequestMethod("GET");
ucon.setDoOutput(true);

ucon.setRequestProperty ("Authorization", "Basic " + encoding);
ucon.connect();

/*
 * Define InputStreams to read from the URLConnection.
 */
InputStream is = ucon.getInputStream();
BufferedInputStream bis = new BufferedInputStream(is);

/*
 * Read bytes to the Buffer until there is nothing more to read(-1).
 */
ByteArrayBuffer bab = new ByteArrayBuffer(50);
int current = 0;
while ((current = bis.read()) != -1) {
    bab.append((byte) current);
}

bis.close();

/* Convert the Bytes read to a String. */
FileOutputStream fos = this._context.openFileOutput(fileName, this._context.MODE_WORLD_READABLE);
fos.write(bab.toByteArray());
fos.close();

可能是密码中的空白造成的吗?