java - 如何使用 old-refreshToken 获取 refreshToken？

Question

1）我成功通过代码获取refreshToken：

    public void Register(String code){
        GoogleTokenResponse response = null;
        response = flow.newTokenRequest(code).setRedirectUri(REDIRECT_URI).execute();
        refreshToken = response.getRefreshToken();                

        GoogleCredential credential = new GoogleCredential().setAccessToken(response.getAccessToken());        

        client = new Drive.Builder(httpTransport, jsonFactory, credential).build();            
    }

现在我得到了refreshToken，它被使用了2）。

2）所以，我想得到客户（类驱动器）。在获取“驱动客户端”的代码下。我认为我应该使用 GoogleRefreshTokenRequest 类通过 refreshToken 获取客户端。真的吗？我确实犯错了？

    public Drive GetClient(String refresh){
            httpTransport = new NetHttpTransport();
            jsonFactory = new JacksonFactory();
            GoogleTokenResponse response = null;
            GoogleRefreshTokenRequest req = new GoogleRefreshTokenRequest(httpTransport, 
jsonFactory, refresh, CLIENT_ID, CLIENT_SECRET);
            req.setGrantType("refresh_token");
            try {
                response = req.execute();
                System.out.println("RF token = " + response.getRefreshToken());
            } catch (IOException ex) {
                Logger.getLogger(GoogleD.class.getName()).log(Level.SEVERE, null, ex);
            }

            GoogleCredential credential = new GoogleCredential().setFromTokenResponse(response);

            client = new Drive.Builder(httpTransport, jsonFactory, credential).build();             

            return client;
        }

3) 而且，我想通过 refreshToken 获得 refreshToken。我的逻辑是对的吗？

1. 通过用户登录获取access_token、refreshToken。
2. 通过 refreshToken 获取客户端（离线）。- 并获得 refreshToken2。
3. 重复 2