我已经为Android应用程序和Web服务器之间的双向消息实现了新的GCM CCS。下行消息（Web-设备）完美地工作。不幸的是，上行消息（设备-Web）在服务器上未收到。它们似乎已经在客户端发送（请参见下面的Android应用程序日志消息），但服务器上没有接收到任何消息。
D/GCM﹕ GcmService start Intent { act=com.google.android.gcm.intent.SEND flg=0x10 pkg=com.google.android.gms cmp=com.google.android.gms/.gcm.GcmService (has extras) } com.google.android.gcm.intent.SEND
我猜测 Android 端没有问题，而是服务器端出了问题。问题在于，我无法找出具体的问题所在，因为连接依然保持着，并且我从 GCM 服务器接收到一些消息，比如 ACKs。那么为什么不能接收正常的消息呢？有人知道吗？
值得一提的是，使用的 Web 服务器是 Glassfish，我在 Servlet 中启动 XMPP 连接。以下是一些片段。
编辑：如我在答案中所述，导致完全无法接收到任何消息的主要问题已经解决。不过，仍然有相当多的消息没有被接收到（约 50%）。
例如，每当用户在 Android 应用程序中进行更改（按下按钮），我就会立即在后台线程上发送 2 条消息，每批之间至少间隔几秒钟。有时我会在服务器上接收到这两个消息，有时我只接收到其中一个，有时甚至什么也不发生…… 这是个很大的问题，尤其是对于以此技术为核心的应用程序。有没有人能够提供进一步的帮助来解决这个问题？
更多信息：我相当确定这与客户端无关，因为每条消息都已经发送，就像你在上面的 logcat 日志中看到的那样，我也会在一段时间后（不是立即，可能是 5 分钟左右）接收到“event：sent”GCM 广播。因此，这一定是与 GCM 或服务器有关的问题。
public class CcsServlet extends HttpServlet
{
private static Logger logger = Logger.getLogger(CcsServlet.class.getName());
public void init(ServletConfig config) throws ServletException
{
CcsManager ccsManager = CcsManager.getInstance();
try
{
ccsManager.connect();
}
catch (Exception e)
{
logger.warning("Cannot connect to CCS server.");
e.printStackTrace();
}
}
}
public class CcsManager
{
private static XMPPConnection connection;
private static Logger logger = Logger.getLogger(CcsManager.class.getName());
public static final String GCM_SERVER = "gcm.googleapis.com";
public static final int GCM_PORT = 5235;
private static CcsManager sInstance = null;
private static final String USERNAME = "xxxxxxxxxx" + "@gcm.googleapis.com";
private static final String PASSWORD = "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx";
public CcsManager()
{
// Add GcmPacketExtension
ProviderManager.getInstance().addExtensionProvider(
GcmPacketExtension.GCM_ELEMENT_NAME,
GcmPacketExtension.GCM_NAMESPACE, new PacketExtensionProvider()
{
public PacketExtension parseExtension(XmlPullParser parser) throws Exception
{
String json = parser.nextText();
return new GcmPacketExtension(json);
}
});
}
public static CcsManager getInstance()
{
if (sInstance == null)
sInstance = new CcsManager();
return sInstance;
}
/**
* Connects to GCM Cloud Connection Server
*/
public void connect() throws IOException, XMPPException
{
ConnectionConfiguration config = new ConnectionConfiguration(GCM_SERVER, GCM_PORT);
config.setSecurityMode(ConnectionConfiguration.SecurityMode.enabled);
config.setReconnectionAllowed(true);
config.setRosterLoadedAtLogin(false);
config.setSendPresence(false);
config.setSocketFactory(SSLSocketFactory.getDefault());
config.setDebuggerEnabled(false);
connection = new XMPPConnection(config);
connection.connect();
connection.addConnectionListener(new ConnectionListener()
{
public void reconnectionSuccessful()
{
logger.info("Reconnecting..");
}
public void reconnectionFailed(Exception e)
{
logger.log(Level.INFO, "Reconnection failed.. ", e);
}
public void reconnectingIn(int seconds)
{
logger.log(Level.INFO, "Reconnecting in %s secs", seconds);
}
public void connectionClosedOnError(Exception e)
{
logger.info("Connection closed on error.");
}
public void connectionClosed()
{
logger.info("Connection closed.");
}
});
// Handle incoming packets
connection.addPacketListener(new PacketListener()
{
public void processPacket(Packet packet)
{
logger.log(Level.INFO, "Received: " + packet.toXML());
Message incomingMessage = (Message) packet;
GcmPacketExtension gcmPacket =
(GcmPacketExtension) incomingMessage.getExtension(GcmPacketExtension.GCM_NAMESPACE);
String json = gcmPacket.getJson();
try
{
@SuppressWarnings("unchecked")
Map<String, Object> jsonObject =
(Map<String, Object>) JSONValue.parseWithException(json);
// present for "ack"/"nack", null otherwise
Object messageType = jsonObject.get("message_type");
if (messageType == null)
{
// Normal upstream data message
handleIncomingDataMessage(jsonObject);
// Send ACK to CCS
String messageId = jsonObject.get("message_id").toString();
String from = jsonObject.get("from").toString();
String ack = createJsonAck(from, messageId);
send(ack);
}
else if ("ack".equals(messageType.toString()))
{
// Process Ack
handleAckReceipt(jsonObject);
}
else if ("nack".equals(messageType.toString()))
{
// Process Nack
handleNackReceipt(jsonObject);
}
else
{
logger.log(Level.WARNING, "Unrecognized message type (%s)",
messageType.toString());
}
}
catch (ParseException e)
{
logger.log(Level.SEVERE, "Error parsing JSON " + json, e);
}
catch (Exception e)
{
logger.log(Level.SEVERE, "Couldn't send echo.", e);
}
}
}, new PacketTypeFilter(Message.class));
// Log all outgoing packets
connection.addPacketInterceptor(new PacketInterceptor()
{
public void interceptPacket(Packet packet)
{
logger.log(Level.INFO, "Sent: {0}", packet.toXML());
}
}, new PacketTypeFilter(Message.class));
connection.login(USERNAME, PASSWORD);
}
}