Servlets facebook java api:fql_查询返回null

我正在尝试使用fql_查询获取登录的名字

我尝试了以下代码：

import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import javax.servlet.http.*;
import javax.servlet.*;
import org.w3c.dom.Document;

import com.google.code.facebookapi.FacebookException;
import com.google.code.facebookapi.FacebookWebappHelper;
import com.google.code.facebookapi.FacebookXmlRestClient;
import com.google.code.facebookapi.IFacebookRestClient;
import org.json.JSONException;


public class Canvas extends HttpServlet {

     private static final String FACEBOOK_USER_CLIENT = "facebook.user.client";
    private String api_key=<API_KEY>;
    private String secret=<SECRET>;


  @Override
    public void doGet (HttpServletRequest req,
                                     HttpServletResponse res)
    throws ServletException, IOException
  {
                    HttpServletRequest request = (HttpServletRequest)req;
                    HttpServletResponse response = (HttpServletResponse)res;

                    HttpSession session = request.getSession(true);
                    IFacebookRestClient<Document> userClient = getUserClient(session);
                    if(userClient == null) {
                      //  logger.debug("User session doesn't have a Facebook API client setup yet. Creating one and storing it in the user's session.");
                        userClient = new FacebookXmlRestClient(api_key, secret);
                        session.setAttribute(FACEBOOK_USER_CLIENT, userClient);
                    }
 FacebookWebappHelper<Document> facebook = new FacebookWebappHelper<Document>(request,      response, api_key, secret, userClient);
                    String nextPage = request.getRequestURI();
                    nextPage = nextPage.substring(nextPage.indexOf("/", 1) + 1); //cut out the first /, the context path and the 2nd /
            //      logger.trace(nextPage);
                    boolean redirectOccurred = facebook.requireLogin(nextPage);
                    if(redirectOccurred) {
                            return;
                    }
                    redirectOccurred = facebook.requireFrame(nextPage);
                    if(redirectOccurred) {
                            return;
                    }

                    long facebookUserID;
                    try {
                         facebookUserID = userClient.users_getLoggedInUser();
                    } catch(FacebookException ex) {
                        response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR,  "Error while fetching user's facebook ID");
/*                          logger.error("Error while getting cached (supplied by request params) value " +
                                         "of the user's facebook ID or while fetching it from the Facebook service " +
                                         "if the cached value was not present for some reason. Cached value = {}", userClient.getCacheUserId());*/
                        return;
                    }
                      PrintWriter out = res.getWriter();
        String query = "Select name from user where uid=" + facebookUserID;
        Document fqlDocument=null;
        try {
        fqlDocument = userClient.fql_query(query);
        } catch (FacebookException e) {
            out.println("error");
        }
    out.println("Hello, Brave new World: " + facebookUserID + " " +  fqlDocument);
    out.close();



  }
  public static FacebookXmlRestClient getUserClient(HttpSession session) {
        return (FacebookXmlRestClient)session.getAttribute(FACEBOOK_USER_CLIENT);
    }

}

结果是：

Hello, Brave new World: <MY_UID>[#document: null]

我保证我收到的uid是正确的。 使用facebook java api 3.0.2最新版本

为什么我从查询中得到一个空文档？ 如果出现问题，为什么查询没有抛出任何相关异常？ 这是我在网上找到的代码，有没有更好的方法来实现我的目标？ 谢谢你所做的一切

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我对这个主题非常陌生，因此对于任何与此主题无关的问题或信息，我深表歉意。

我使用TinyFBClient而不是facebook java api解决了这个问题

tinyFbClient允许发送实际的facebook api命令，该命令允许我在不使用fql查询的情况下获取应用程序的所有相关信息

facebook api:

TinyfB客户：

代码示例：

HttpServletRequest request = (HttpServletRequest)req;
String sessionKey = request.getParameter("fb_sig_session_key");
TinyFBClient fb = new TinyFBClient(this.api_key,this.secret,sessionKey);
TreeMap tm = new TreeMap();

tm.put("uid","");

String friendList = fb.call("friends.get", tm);

PrintWriter out = res.getWriter();
out.println(friendList);

out.close();

}

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嗯，还没有找到答案，我将尝试TinyFbClient而不是JavaAPI客户端。也许我会有更好的运气