String filePath = StringUtils.trimToEmpty(req.getParameter("filepath")).trim();
AppKeyPair appKeyPair = new AppKeyPair(appKey, appSecret);
WebAuthSession was = new WebAuthSession(appKeyPair, Session.AccessType.DROPBOX);
AccessTokenPair accessToken = new AccessTokenPair(tokenKey, tokenSecret);
was.setAccessTokenPair(accessToken);
DropboxAPI<WebAuthSession> api = new DropboxAPI<WebAuthSession>(was);
try {
Entry meta = api.metadata(filePath, 1, null, false, null);