Exception on trying to access the entity using key in GAE datastore

Question

I am actually building a chatroom using GAE the problem is that i am storing the clientid and token in chatrromservlet and accessin them in the sayservlet using datastore key but when I am trying to access the datastore from sayservlet using the key i am getting an exception that the entity with the key is not found.

My chatroomservlet

    String clientid = request.getParameter("clientid");
    ChannelService channelService = ChannelServiceFactory.getChannelService();

    String token = channelService.createChannel(clientid);
    channelService.sendMessage(new ChannelMessage(token, "Hello World"));
    System.out.println("token is ="+token);

    JSONObject job=new JSONObject();
    job.put("token",token);

    Key userkey=KeyFactory.createKey("users", "user1");
    System.out.println("user key in chatroom "+ userkey);
    Entity ent=new Entity("user");
    ent.setProperty("clientid", clientid);
    ent.setProperty("token", token);


    DatastoreService datastore = DatastoreServiceFactory.getDatastoreService();
    datastore.put(ent);
    System.out.println(ent);

and the say servlet is

            String message = request.getParameter("message");
            String clientid = request.getParameter("clientid");
            System.out.println(message);

            Key userkey=KeyFactory.createKey("users", "user1");
            Entity entity;
            DatastoreService datastore = DatastoreServiceFactory
                    .getDatastoreService();
            entity = datastore.get(userkey);
            String token = (String) entity.getProperty("token");
            System.out.println("token frm db ="+token);

            ChannelService channelService = ChannelServiceFactory.getChannelService();
            channelService.sendMessage(new ChannelMessage(token, "Hello World"));
            System.out.println("message is ="+message);
            System.out.println("cid is ="+clientid);

please help me if there is any mistake while accessing.

score 0 · Answer 1 · answered Sep 27 '13 at 19:05

It looks like in your chatroomservlet you create an entity but you don't use your generated key. Thus, when you lookup by that key in the say servlet, the datastore won't be able to find the entity.

Your chatroomservlet should create the entity using the userkey:

    Key userkey=KeyFactory.createKey("users", "user1");
    System.out.println("user key in chatroom "+ userkey);
    Entity ent=new Entity(userkey);

Exception on trying to access the entity using key in GAE datastore

1 Answers1