How to Get Facebook Friends List in Java Servlet or JSP in 5 Easy Steps Using RestFB

Updated: July 9, 2014. (old post given below)

In the link that open Facebook Loging dialog, you need to specify one or more permissions that user must grant you, only then your applications can fetch associated data or performs a particular operation. If you do not specify any permission, default basic_info was used in API V1. In latest V2 API, the default is named to public_profile.

If you are developing a new Facebook App or your Facebook App was not active for last couple of months, the Facebook by default would use API 2.0 version to serve your requests that no more allows fetching all Facebook friends list with basic_info permission. (Reference) basic_info permission no more exist, it has been replaced with public_profile permission (the default) which contains same info except the friends list. The all login user friends list were earlier available under basic_info.

Another permission user_friends is introduced in version 2.0, but it do not return all friends of the login user under /me/friends endpoint (we would use from RestFB), but only those friends who are already using the app you are going to login. If you are new to fetching Facebook friends, more accurately we should call it, facebook friends who are using-app. Here I share some steps you need to follow:

1. Create an app at Facebook Apps. Make sure you have configured/noted following things:

1. Go to https://developers.facebook.com/apps/ and choose Create a New App under Apps Tab.
   
   
2. Note your App ID and App Secret, it would be used in our app code.
   
   
3. As we are using Facebook Login from website, so under Settings->Basic tab, click Add Platform. and choose Website. Don't forget to input Contact Email (on same form), its mandatory. For my test app, my app page looks like this:
   
   
4. Under left menu, choose Status & Review, and Activate App for general public clicking the right button labeled as NO, make it YES. so that anybody can use it to login at your website. See below image how it should look.
   
   

2. Create a login page with Facebook Login link. Its to open Facebook authentication dialog. Here is the link code in index.jsp, that contains this link.

<a href="https://graph.facebook.com/oauth/authorize?client_id=1524731954416948&scope=email,user_friends&redirect_uri=<%=URLEncoder.encode("http://localhost:8080/bitspedia-lab/FriendsListServlet")%>">Click Here to Login Using Facebook</a>

3. When user click on the link, it open the Facebook Authentication dialog.

4. After the Login window, Facebook would show the Authorization Box, its only displayed in case of permissions other than basic_profile are used. This window looks like:

5. After user allows the asked permissions. The Facebook would redirect the user browser to the link you provided above opening Login Dialog under redirect_uri. When Facebook redirect to provided redirect_uri, it also sends a parameters (as HTTP request parameter) with the name of code. We would use the code parameter is used to retrieve access_token. We would do so in FriendsListServlet.

6. Below code belongs to FriendsListServlet. It seems lengthy, but performs very simple task. The brief explanation is given after the code section.

package com.bitspedia.servlets;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.net.URLEncoder;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.restfb.Connection;
import com.restfb.DefaultFacebookClient;
import com.restfb.FacebookClient;
import com.restfb.exception.FacebookException;
import com.restfb.types.User;

public class FriendsListServlet extends HttpServlet {
    public static String APP_ID = "write your app id here ";
    public static String APP_SECRET = "write your app secret here";
    private static final long serialVersionUID = 1L;

 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

  String code = request.getParameter("code");

  String URLEncodedRedirectURI = URLEncoder.encode("http://localhost:8080/bitspedia-lab/FriendsListServlet");
  String MY_ACCESS_TOKEN = "";

  String authURL = "https://graph.facebook.com/oauth/access_token?" +
                "client_id=" + FriendsListServlet.APP_ID + "&" +
                "redirect_uri=" + URLEncodedRedirectURI + "&" +
                "client_secret=" + FriendsListServlet.APP_SECRET + "&" +
                "code=" + code;

  URL url = new URL(authURL);

  String result = readURL(url);
  String[] pairs = result.split("&");

  for (String pair : pairs) {

   String[] kv = pair.split("=");
   if (kv[0].equals("access_token")) {
    MY_ACCESS_TOKEN = kv[1];
   }
  }

  FacebookClient facebookClient = new DefaultFacebookClient(MY_ACCESS_TOKEN, FriendsListServlet.APP_SECRET);

  Connection friends = null;
 
  try {
            User loginUser = facebookClient.fetchObject("me", User.class);
            request.setAttribute("loginUser", loginUser);
            friends = facebookClient.fetchConnection("/me/friends", User.class);

  } catch (FacebookException e) {
    e.printStackTrace();
  }

  List friendsList = friends.getData();
  request.setAttribute("friendsList",friendsList);

  getServletConfig().getServletContext().getRequestDispatcher("/FriendsList.jsp").forward(request, response);
 }

 private String readURL(URL url) throws IOException {

  ByteArrayOutputStream baos = new ByteArrayOutputStream();
  InputStream is = url.openStream();

  int r;

  while ((r = is.read()) != -1) {
   baos.write(r);
  }

  return new String(baos.toByteArray());

 }
}

1. code parameter is submitted to our servlet by Facebook. We have retrieved it from request in Line 28. It would be used later to fetch access_token. access_token is another alphanumeric long string that is used instantiate FacebookDefaultClient object (a RestFB Class). This client object would be actually use to make different API call to Facebook server.
2. Facebook provides another URL to retrieve access_token, this URL is https://graph.facebook.com/oauth/access_token?, it receives a couple of parameters and returns access_token and time when this token would expire. These parameters are submitted to get access_token:
1. client_id (this is APP ID)
2. redirect_uri (it must be same as you used in dialog box, if different, the access_token would not be generated)
3. client secret (this is APP Secret), to make sure only authorized persons could make API calls on behalf of an App. You should not share it with others.
4. code, this is same code that was submitted to the Servlet.
3. The readURL method in Line 41 actually makes the request to fetch access_token, it just returns the string that contains access_tokens and epires attributes.
4. The format of the string return by readURL is access_token=CAAVq7RqWb&expires=5158143, now we need extract the access_token value from it. Line 41-50 does so.
5. Line 52 instantiate DefaultFacebookClient object that takes access_token and APP Secret in it constructor. The DefaultFacebookClient object is used to make different API calls.
6. Then we have retrieve the login user info and his list of friends who are using our app and stored it into request arguments, from where the JSP page would retrieve and display the content as output.
7. Line 68 dispatch the request to view i.e. FriendsList.jsp

7. The JSP page output is as follows.

8. Here is the JSP code

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%><br />
<!DOCTYPE html><br />
<html><br />
<head><br />
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><br />
<title>BitsPedia - Facebook Friends List</title><br />
</head><br />
<body><br />
    <h1>Login User Information</h1><br />
    <ul><br />
        <li>User Facebook ID: <c:out value="${loginUser.id}" /></li><br />
        <li>First Name: <c:out value="${loginUser.firstName}" /></li><br />
        <li>Last Name: <c:out value="${loginUser.lastName}"/> </li><br />
    </ul><br />
 <h1>Friends List - Who are using the App</h1><br />
 <table><br />
  <c:forEach items="${friendsList}" var="user"><br />
   <tr><br />
    <td><c:out value="${user.name}" /></td><br />
    <td><img src='https://graph.facebook.com/<c:out value="${user.id}"/>/picture' /><br />
    </td><br />
   </tr><br />
  </c:forEach><br />
 </table><br />
</body><br />
</html>

If you know even very little about JSP, you can see have just displayed some attributes of loginUser key we inserted into request as an attribute. Then I have iterated the friends list to display the name and picture of each friend.

You can Download Complete Source Code too.

Share your issues under comments, i would reply to address in this or new posts. 

=====================================================================
Old Post: (November 1, 2012)

Here we will see how to get Facebook friends list in just 5 steps:

1. Create a new Facebook App and write down its App ID (aka Client ID or API Key) and App Secret (aka Client Secret). Set Site URL = http://localhost:8080/facebookfriends

2. In your HTML or JSP page Make a hyperlink, to send user at Facebook Login page, like this:

Click Here

Complete source code is available:Click Here to view.

3. After successful authentication, Facebook will redirect user to the URL passed in step 2 under redirect_uri

4. When Facebook redirect the user, it sends a "code" parameter to our servlet, we can access this "code" like this: (request is HttpServletRequest object)

String code = request.getParameter("code");

5. The "code" and App Secret is passed to Facebook to get "access_token". Access Token is what we need to get friends list. This is how you can get "access_token":

String MY_ACCCESS_TOKEN;
        String authURL = "https://graph.facebook.com/oauth/access_token?client_id=CLIENT_ID&redirect_uri=http://localhost:8080/facebookfriends/FriendsListServlet&client_secret=APP_SECRET&code=" + code ;
        URL url = new URL(authURL);
        String result = readURL(url);
        String[] pairs = result.split("&");

        for (String pair : pairs) {
          String[] kv = pair.split("=");          
          if (kv[0].equals("access_token")) {
              MY_ACCESS_TOKEN = kv[1];
          }          
        } // end of for loop

        // here is the readURL method
        private String readURL(URL url) throws IOException {
          ByteArrayOutputStream baos = new ByteArrayOutputStream();
          InputStream is = url.openStream();
          int r;
          while ((r = is.read()) != -1) {
             baos.write(r);
          }
          return new String(baos.toByteArray());
       }

Once you have the Access Token, getting friends lists is a matter of 2 lines of code:

FacebookClient facebookClient = new DefaultFacebookClient(MY_ACCESS_TOKEN);
   Connection friends = facebookClient.fetchConnection("me/friends", User.class);
   List friendsList = friends.getData();

   //Lets display some friends info on console

   for (User user : friendsList) {
     System.out.println(user.getId() + " : " user.getName());
   }

Don't forget to replace the CLIENT_ID and APP_SECRET in above code snippets (and attached sample project) with actual values you got in Step 1.


Here is the final output: