import com.google.api.client.googleapis.auth.oauth2.GoogleAuthorizationCodeRequestUrl; //导入依赖的package包/类
private void openBrowserAndGetToken() {
  // Step 1: Authorize -->
  String authorizationUrl = new GoogleAuthorizationCodeRequestUrl(
      CLIENT_ID, REDIRECT_URI, SCOPES).build();
  try {
    // Point or redirect your user to the authorizationUrl.
    java.awt.Desktop.getDesktop().browse(new URI(authorizationUrl));
  } catch (Exception e) {
    LOGGER.warning("Unable to open browser: " + e.toString());
    LOGGER.info("Go to: " + authorizationUrl);
    JOptionPane.showMessageDialog(optionsFrame, "Cannot open browser. Check the console for the necessary URL.",
                                  "Error", JOptionPane.ERROR_MESSAGE);
  }
  // End of Step 1 <--
}
 

import com.google.api.client.googleapis.auth.oauth2.GoogleAuthorizationCodeRequestUrl; //导入依赖的package包/类
@RequestMapping(value = "/ask", method = RequestMethod.GET)
	public void ask(HttpServletResponse response) throws IOException {
		
		// Step 1: Authorize --> ask for auth code
		String url = new GoogleAuthorizationCodeRequestUrl(connection.getClientSecrets(), 
				connection.getRedirectUrl(), Global.SCOPES)
//				.setApprovalPrompt("auto")
				.setApprovalPrompt("force")
				.build();
		
		System.out.println("Go to the following link in your browser: ");
		System.out.println(url);
		
		response.sendRedirect(url);
	}
 

import com.google.api.client.googleapis.auth.oauth2.GoogleAuthorizationCodeRequestUrl; //导入依赖的package包/类
@Override
public String obtainVerificationCodeFromUserInteraction(
    String title, GoogleAuthorizationCodeRequestUrl authCodeRequestUrl) {
  GoogleLoginCopyAndPasteDialog dialog =
      new GoogleLoginCopyAndPasteDialog(
          authCodeRequestUrl,
          AccountMessageBundle.message("login.service.copyandpaste.title.text"));
  dialog.show();
  if (dialog.getExitCode() == DialogWrapper.CANCEL_EXIT_CODE) {
    return null;
  }

  return Strings.emptyToNull(dialog.getVerificationCode());
}
 

import com.google.api.client.googleapis.auth.oauth2.GoogleAuthorizationCodeRequestUrl; //导入依赖的package包/类
/** Initialize the verification code dialog. */
public GoogleLoginCopyAndPasteDialog(
    GoogleAuthorizationCodeRequestUrl requestUrl, String message) {
  super(true);
  urlString = requestUrl.build();

  if (message != null) {
    setTitle(message);
  } else {
    setTitle(TITLE);
  }

  init();
}
 

import com.google.api.client.googleapis.auth.oauth2.GoogleAuthorizationCodeRequestUrl; //导入依赖的package包/类
/**
 * Retrieve the authorization URL.
 * 
 * @param emailAddress User's e-mail address.
 * @param state State for the authorization URL.
 * @return Authorization URL to redirect the user to.
 * @throws IOException Unable to load client_secrets.json.
 */
public static String getAuthorizationUrl(String emailAddress,
        String state) throws IOException {
    GoogleAuthorizationCodeRequestUrl urlBuilder = getFlow()
            .newAuthorizationUrl().setRedirectUri(REDIRECT_URI)
            .setState(state);
    urlBuilder.set("user_id", emailAddress);
    return urlBuilder.build();
}
 

import com.google.api.client.googleapis.auth.oauth2.GoogleAuthorizationCodeRequestUrl; //导入依赖的package包/类
@SuppressWarnings("unused")
private static String getRefreshToken() throws IOException {
    String client_id = System.getenv("PICASSA_CLIENT_ID");
    String client_secret = System.getenv("PICASSA_CLIENT_SECRET");
    
    // Adapted from http://stackoverflow.com/a/14499390/1447621
    String redirect_uri = "http://localhost";
    String scope = "http://picasaweb.google.com/data/";
    List<String> scopes;
    HttpTransport transport = new NetHttpTransport();
    JsonFactory jsonFactory = new JacksonFactory();

    scopes = new LinkedList<String>();
    scopes.add(scope);
    GoogleAuthorizationCodeFlow flow = new GoogleAuthorizationCodeFlow.Builder(transport, jsonFactory, client_id, client_secret, scopes).build();
    GoogleAuthorizationCodeRequestUrl url = flow.newAuthorizationUrl();
    url.setRedirectUri(redirect_uri);
    url.setApprovalPrompt("force");
    url.setAccessType("offline");
    String authorize_url = url.build();
   
    // paste into browser to get code
    System.out.println("Put this url into your browser and paste in the access token:");
    System.out.println(authorize_url);
    
    Scanner scanner = new Scanner(System.in);
    String code = scanner.nextLine();
    scanner.close();

    flow = new GoogleAuthorizationCodeFlow.Builder(transport, jsonFactory, client_id, client_secret, scopes).build();
    GoogleTokenResponse res = flow.newTokenRequest(code).setRedirectUri(redirect_uri).execute();
    String refreshToken = res.getRefreshToken();
    String accessToken = res.getAccessToken();

    System.out.println("refresh:");
    System.out.println(refreshToken);
    System.out.println("access:");
    System.out.println(accessToken);
    return refreshToken;
}
 

import com.google.api.client.googleapis.auth.oauth2.GoogleAuthorizationCodeRequestUrl; //导入依赖的package包/类
/**
 * Generates a consent page url.
 * @return A consent page url string for user redirection.
 */
public String getAuthorizationUrl() {
  GoogleAuthorizationCodeRequestUrl urlBuilder =
      new GoogleAuthorizationCodeRequestUrl(
      clientSecrets.getWeb().getClientId(),
      clientSecrets.getWeb().getRedirectUris().get(0), SCOPES);;
 return urlBuilder.build();
}
 

import com.google.api.client.googleapis.auth.oauth2.GoogleAuthorizationCodeRequestUrl; //导入依赖的package包/类
@Override
public String obtainVerificationCodeFromUserInteraction(
    String title, GoogleAuthorizationCodeRequestUrl authCodeRequestUrl) {
  throw new RuntimeException("Not to be called."); //$NON-NLS-1$
}
 

import com.google.api.client.googleapis.auth.oauth2.GoogleAuthorizationCodeRequestUrl; //导入依赖的package包/类
/**
 * Returns a URL through which users can login.
 *
 * @param redirectUrl URL to which the login result is directed. For example, a local web
 *     server listening on the URL can receive an authorization code from it.
 */
public static String getGoogleLoginUrl(String redirectUrl) {
  return new GoogleAuthorizationCodeRequestUrl(Constants.getOAuthClientId(), redirectUrl,
      GoogleLoginService.OAUTH_SCOPES).toString();
}
 

import com.google.api.client.googleapis.auth.oauth2.GoogleAuthorizationCodeRequestUrl; //导入依赖的package包/类
public String execute(
		HttpServletRequest request, HttpServletResponse response)
	throws Exception {

	ThemeDisplay themeDisplay = (ThemeDisplay)request.getAttribute(
		WebKeys.THEME_DISPLAY);

	String cmd = ParamUtil.getString(request, Constants.CMD);

	String redirectUri = PortalUtil.getPortalURL(request) + _REDIRECT_URI;

	if (cmd.equals("login")) {
		GoogleAuthorizationCodeFlow flow = getFlow();

		GoogleAuthorizationCodeRequestUrl
			googleAuthorizationCodeRequestUrl = flow.newAuthorizationUrl();

		googleAuthorizationCodeRequestUrl.setRedirectUri(redirectUri);

		String url = googleAuthorizationCodeRequestUrl.build();

		response.sendRedirect(url);
	}
	else if (cmd.equals("token")) {
		HttpSession session = request.getSession();

		String code = ParamUtil.getString(request, "code");

		if (Validator.isNotNull(code)) {
			Credential credential = exchangeCode(code, redirectUri);

			Userinfo userinfo = getUserInfo(credential);

			User user = setGoogleCredentials(
				session, themeDisplay.getCompanyId(), userinfo);

			if ((user != null) &&
				(user.getStatus() == WorkflowConstants.STATUS_INCOMPLETE)) {

				redirectUpdateAccount(request, response, user);

				return null;
			}

			PortletURL portletURL = PortletURLFactoryUtil.create(
				request, PortletKeys.FAST_LOGIN, themeDisplay.getPlid(),
				PortletRequest.RENDER_PHASE);

			portletURL.setWindowState(LiferayWindowState.POP_UP);

			portletURL.setParameter(
				"struts_action", "/login/login_redirect");

			response.sendRedirect(portletURL.toString());
		}
	}

	return null;
}