Google OAuth 2.0 Example using Scribe Java

In this example we are going to see about how to use Google OAuth 2.0 using Scribe Java
Google OAuth 2.0 Example

Google20Example.java
import java.util.Random;
import java.util.Scanner;
import com.github.scribejava.core.builder.ServiceBuilder;
import com.github.scribejava.apis.GoogleApi20;
import com.github.scribejava.core.model.OAuth2AccessToken;
import com.github.scribejava.core.model.OAuthRequest;
import com.github.scribejava.core.model.Response;
import com.github.scribejava.core.model.Verb;
import com.github.scribejava.core.oauth.OAuth20Service;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

public abstract class Google20Example {

    private static final String NETWORK_NAME = "G+";
    private static final String PROTECTED_RESOURCE_URL = "https://www.googleapis.com/plus/v1/people/me";

    public static void main(String... args) throws IOException {
        // Replace these with your client id and secret
        final String clientId = "your client id";
        final String clientSecret = "your client secret";
        final String secretState = "secret" + new Random().nextInt(999_999);
        final OAuth20Service service = new ServiceBuilder()
                .apiKey(clientId)
                .apiSecret(clientSecret)
                .scope("profile") // replace with desired scope
                .state(secretState)
                .callback("http://example.com/callback")
                .build(GoogleApi20.instance());
        final Scanner in = new Scanner(System.in, "UTF-8");

        System.out.println("=== " + NETWORK_NAME + "'s OAuth Workflow ===");
        System.out.println();

        // Obtain the Authorization URL
        System.out.println("Fetching the Authorization URL...");
        //pass access_type=offline to get refresh token
        //https://developers.google.com/identity/protocols/OAuth2WebServer#preparing-to-start-the-oauth-20-flow
        final Map additionalParams = new HashMap<>();
        additionalParams.put("access_type", "offline");
        //force to reget refresh token (if usera are asked not the first time)
        additionalParams.put("prompt", "consent");
        final String authorizationUrl = service.getAuthorizationUrl(additionalParams);
        System.out.println("Got the Authorization URL!");
        System.out.println("Now go and authorize ScribeJava here:");
        System.out.println(authorizationUrl);
        System.out.println("And paste the authorization code here");
        System.out.print(">>");
        final String code = in.nextLine();
        System.out.println();

        System.out.println("And paste the state from server here. We have set 'secretState'='" + secretState + "'.");
        System.out.print(">>");
        final String value = in.nextLine();
        if (secretState.equals(value)) {
            System.out.println("State value does match!");
        } else {
            System.out.println("Ooops, state value does not match!");
            System.out.println("Expected = " + secretState);
            System.out.println("Got      = " + value);
            System.out.println();
        }

        // Trade the Request Token and Verfier for the Access Token
        System.out.println("Trading the Request Token for an Access Token...");
        OAuth2AccessToken accessToken = service.getAccessToken(code);
        System.out.println("Got the Access Token!");
        System.out.println("(if your curious it looks like this: " + accessToken
                + ", 'rawResponse'='" + accessToken.getRawResponse() + "')");

        System.out.println("Refreshing the Access Token...");
        accessToken = service.refreshAccessToken(accessToken.getRefreshToken());
        System.out.println("Refreshed the Access Token!");
        System.out.println("(if your curious it looks like this: " + accessToken
                + ", 'rawResponse'='" + accessToken.getRawResponse() + "')");
        System.out.println();

        // Now let's go and ask for a protected resource!
        System.out.println("Now we're going to access a protected resource...");
        while (true) {
            System.out.println("Paste fieldnames to fetch (leave empty to get profile, 'exit' to stop example)");
            System.out.print(">>");
            final String query = in.nextLine();
            System.out.println();

            final String requestUrl;
            if ("exit".equals(query)) {
                break;
            } else if (query == null || query.isEmpty()) {
                requestUrl = PROTECTED_RESOURCE_URL;
            } else {
                requestUrl = PROTECTED_RESOURCE_URL + "?fields=" + query;
            }

            final OAuthRequest request = new OAuthRequest(Verb.GET, requestUrl, service);
            service.signRequest(accessToken, request);
            final Response response = request.send();
            System.out.println();
            System.out.println(response.getCode());
            System.out.println(response.getBody());

            System.out.println();
        }
    }
}