基于自己参与所开发的游戏项目用到的 Java-WebSocket，做一些经验总结。
本文相关基础代码依赖于：
https://github.com/TooTallNate/Java-WebSocket
https://github.com/0xZhangKe/WebSocketDemo
项目里使用 Java-WebSocket + Protocol Buffers，做的基础实现，游戏场景里，当前用户只存在一个游戏房间。没有IM的那种最新会话列表里面，会有多个聊天会话（群聊、单聊），要维护多个聊天室或房间内的场景。
1.关于心跳的维护
每隔15s（相关参数数据以自己项目里的设置来说的，本文后面的数据也一样）向服务器发送一次心跳类型请求。服务器那边也需要知道客户端这边的心跳维护请求，一直没有断开，如果服务器连续30s收不到心跳，认为用户离线。
比如，在房间内游戏里的玩家，就会在UI展现上看到对方离线的标记。
/**
* 心跳管理工具类
*/
public class HeartTimerUtils {
private static final HeartTimerUtils ourInstance = new HeartTimerUtils();
private Timer timer;
private TimerTask timerTask;
private HeartTimerListener listener;
public static HeartTimerUtils getInstance() {
return ourInstance;
}
private HeartTimerUtils() {
}
public void startHeartData() {
stopTimer();
if(timer == null){
timer = new Timer();
timerTask = new TimerTask() {
@Override
public void run() {
if(listener != null){
listener.sendHeartData();
}
}
};
timer.schedule(timerTask,1000,15000);//延时1s，每隔15000毫秒执行一次run方法
}
}
public void stopTimer(){
if (timer != null) {
timer.cancel();
timer = null;
}
if (timerTask != null) {
timerTask.cancel();
timerTask = null;
}
}
public void setListener(HeartTimerListener listener) {
this.listener = listener;
}
public interface HeartTimerListener{
void sendHeartData();
}
public void closeTimer(){
stopTimer();
listener = null;
}
}
/**
* 已经绑定了 WebSocketService 服务的 Activity
*/
public abstract class WebSocketActivity extends BaseActivity implements HeartTimerUtils.HeartTimerListener {
...省略
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (!MainApplication.getInstance().isWebSocketManagerConnected()) {
MainApplication.getInstance().initWebSocket();
} else {
HeartTimerUtils.getInstance().stopTimer();
onConnectedEvent();
}
HeartTimerUtils.getInstance().setListener(this);
try {
if (WebSocketHandler.getDefault() != null) {
WebSocketHandler.getDefault().addListener(socketListener);
}
} catch (Exception e) {
}
}
/**
* 发送自定义类型proto数据（二进制）
*/
public void sendData(byte[] text) {
if (WebSocketHandler.getDefault() != null) {
WebSocketHandler.getDefault().send(text);
}
}
/**
* WebSocket 连接成功，向服务器发送登录类型事件请求
*/
public void onConnectedEvent() {
LoginProtocalRequest request = new LoginProtocalRequest();
int userId;
if (!TextUtils.isEmpty(CommonUtil.getUid())) {
userId = Integer.parseInt(CommonUtil.getUid());
} else {
userId = 0;
}
LoginRequest req = LoginRequest.newBuilder().setToken(Md5Utils.encrypt(CommonUtil.getAccessToken())).setUserId(userId).setRoomId(roomId).build();
request.op = ProtocolMap.LOGIN_OP_REQ;
request.data = req.toByteArray();
sendData(request.getByteData());
}
@Override
protected void onDestroy() {
super.onDestroy();
if (WebSocketHandler.getDefault() != null) {
WebSocketHandler.getDefault().removeListener(socketListener);
}
}
public void destoryWebSocket() {
HeartTimerUtils.getInstance().stopTimer();
if (WebSocketHandler.getDefault() != null) {
WebSocketHandler.getDefault().disConnect();
WebSocketHandler.getDefault().destroy();
}
}
@Override
public void sendHeartData() {
BaseProtocol protocol = new BaseProtocol();
protocol.op = ProtocolMap.SOCKET_HEART;
sendData(protocol.getByteData());
}
...省略
}
所用到具体业务的 Activity,只需要继承 WebSocketActivity，去实现自己发消息和收消息的业务。
Websocket本身有封装好 ping/pong 事件来维护心跳，通过发送 ping/pong 来确保连接的可用，客户端发送 ping 帧，服务端响应 pong 帧。只是我们项目里没用这个来维护，自己写的逻辑来维护的。
/**
* 接收到 Ping 数据
*/
public class PingResponse implements Response {
private Framedata framedata;
PingResponse() {
}
@Override
public Framedata getResponseData() {
return framedata;
}
@Override
public void setResponseData(Framedata responseData) {
this.framedata = responseData;
}
@Override
public void onResponse(IResponseDispatcher dispatcher, ResponseDelivery delivery) {
dispatcher.onPing(framedata, delivery);
}
@Override
public void release() {
framedata = null;
ResponseFactory.releasePingResponse(this);
}
@Override
public String toString() {
return String.format("[@PingResponse%s->Framedata:%s]",
hashCode(),
framedata == null ?
"null" :
framedata.toString());
}
/**
* 接收到 Pong
*/
public class PongResponse implements Response {
private Framedata framedata;
PongResponse() {
}
@Override
public Framedata getResponseData() {
return framedata;
}
@Override
public void setResponseData(Framedata responseData) {
this.framedata = responseData;
}
@Override
public void onResponse(IResponseDispatcher dispatcher, ResponseDelivery delivery) {
dispatcher.onPong(this.framedata, delivery);
}
@Override
public void release() {
framedata = null;
ResponseFactory.releasePongResponse(this);
}
@Override
public String toString() {
return String.format("[@PongResponse%s->Framedata:%s]",
hashCode(),
framedata == null ?
"null" :
framedata.toString());
}
}
/**
* 创建 {@link Response} 的工厂类
*/
public class ResponseFactory {
private static final int POOL_SIZE = 7;
private static Queue ERROR_RESPONSE_POOL = new ArrayDeque<>(POOL_SIZE);
private static Queue TEXT_RESPONSE_POOL = new ArrayDeque<>(POOL_SIZE);
private static Queue BYTE_BUFFER_RESPONSE_POOL = new ArrayDeque<>(POOL_SIZE);
private static Queue PING_RESPONSE_POOL = new ArrayDeque<>(POOL_SIZE);
private static Queue PONG_RESPONSE_POOL = new ArrayDeque<>(POOL_SIZE);
public static ErrorResponse createErrorResponse(){
ErrorResponse response = ERROR_RESPONSE_POOL.poll();
if(response == null){
response = new ErrorResponse();
}
return response;
}
public static Response createTextResponse() {
Response response = TEXT_RESPONSE_POOL.poll();
if (response == null) {
response = new TextResponse();
}
return response;
}
public static Response createByteBufferResponse() {
Response response = BYTE_BUFFER_RESPONSE_POOL.poll();
if (response == null) {
response = new ByteBufferResponse();
}
return response;
}
public static Response createPingResponse() {
Response response = PING_RESPONSE_POOL.poll();
if (response == null) {
response = new PingResponse();
}
return response;
}
public static Response createPongResponse() {
Response response = PONG_RESPONSE_POOL.poll();
if (response == null) {
response = new PongResponse();
}
return response;
}
static void releaseErrorResponse(ErrorResponse response){
ERROR_RESPONSE_POOL.offer(response);
}
static void releaseTextResponse(TextResponse response) {
TEXT_RESPONSE_POOL.offer(response);
}
static void releaseByteBufferResponse(ByteBufferResponse response) {
BYTE_BUFFER_RESPONSE_POOL.offer(response);
}
static void releasePingResponse(PingResponse response) {
PING_RESPONSE_POOL.offer(response);
}
static void releasePongResponse(PongResponse response) {
PONG_RESPONSE_POOL.offer(response);
}
}
2.关于断线重连
断线重连，分为几种情况：
一、客户端处于无网状态或弱网的情况，这时断开了。当客户端监听到网络恢复，重新给 socket 重连上；
二、当客户端遇到弱网的情况，导致 socket 连接断开 onDisconnect ，此时网络是连接的状态。这时客户端发消息和收消息都会失败。客户端重连可能也连接不上，这时需要客户端多次重连网络恢复到正常时，才能连接成功。
三、客户端发送协议消息是，发送失败了 onSendDataError 时，来触发重连操作。
/**
* 重连接口
*/
public interface ReconnectManager {
/**
* 是否正在重连
*/
boolean reconnecting();
/**
* 开始重连
*/
void startReconnect();
/**
* 停止重连
*/
void stopReconnect();
/**
* 连接成功
*/
void onConnected();
/**
* 连接失败
*
* @param th 失败原因
*/
void onConnectError(Throwable th);
/**
* 销毁资源
*/
void destroy();
/**
* 连接成功或失败事件
*/
interface OnConnectListener {
void onConnected();
void onDisconnect();
}
}
/**
* WebSocket 管理类
*/
public class WebSocketManager {
private static final String TAG = "WSManager";
private WebSocketSetting mSetting;
private WebSocketWrapper mWebSocket;
/**
* 注册的监听器集合
*/
private ResponseDelivery mDelivery;
private ReconnectManager mReconnectManager;
private SocketWrapperListener mSocketWrapperListener;
/**
* 当前是否已销毁
*/
private boolean destroyed = false;
/**
* 用户调用了 disconnect 方法后为 true
*/
private boolean disconnect = false;
private WebSocketEngine mWebSocketEngine;
private ResponseProcessEngine mResponseProcessEngine;
WebSocketManager(WebSocketSetting setting,
WebSocketEngine webSocketEngine,
ResponseProcessEngine responseProcessEngine) {
this.mSetting = setting;
this.mWebSocketEngine = webSocketEngine;
this.mResponseProcessEngine = responseProcessEngine;
mDelivery = mSetting.getResponseDelivery();
if (mDelivery == null) {
mDelivery = new MainThreadResponseDelivery();
}
mSocketWrapperListener = getSocketWrapperListener();
if (mWebSocket == null) {
mWebSocket = new WebSocketWrapper(this.mSetting, mSocketWrapperListener);
}
start();
}
/**
* 启动，调用此方法开始连接
*/
public WebSocketManager start() {
if (mWebSocket == null) {
mWebSocket = new WebSocketWrapper(this.mSetting, mSocketWrapperListener);
}
if (mWebSocket.getConnectState() == 0) {
reconnect();
}
return this;
}
/**
* WebSocket 是否已连接
*/
public boolean isConnect() {
return mWebSocket != null && mWebSocket.getConnectState() == 2;
}
/**
* 设置重连管理类。
* 用户可根据需求设置自己的重连管理类，只需要实现接口即可
*/
public void setReconnectManager(ReconnectManager reconnectManager) {
this.mReconnectManager = reconnectManager;
}
/**
* 通过 {@link ReconnectManager} 开始重接
*/
public WebSocketManager reconnect() {
disconnect = false;
if (mReconnectManager == null) {
mReconnectManager = getDefaultReconnectManager();
}
if (!mReconnectManager.reconnecting()) {
mReconnectManager.startReconnect();
}
return this;
}
/**
* 使用新的 Setting 重新创建连接，同时会销毁之前的连接
*/
public WebSocketManager reconnect(WebSocketSetting setting) {
disconnect = false;
if (destroyed) {
LogUtil.e(TAG, "This WebSocketManager is destroyed!");
return this;
}
this.mSetting = setting;
if (mWebSocket != null) {
mWebSocket.destroy();
mWebSocket = null;
}
start();
return this;
}
/**
* 断开连接，断开后可使用 {@link this#reconnect()} 方法重新建立连接
*/
public WebSocketManager disConnect() {
disconnect = true;
if (destroyed) {
LogUtil.e(TAG, "This WebSocketManager is destroyed!");
return this;
}
if (mWebSocket.getConnectState() != 0) {
mWebSocketEngine.disConnect(mWebSocket, mSocketWrapperListener);
}
return this;
}
/**
* 发送文本数据
*/
public void send(String text) {
if (TextUtils.isEmpty(text)) {
return;
}
Request request = RequestFactory.createStringRequest();
request.setRequestData(text);
sendRequest(request);
}
/**
* 发送 byte[] 数据
*/
public void send(byte[] bytes) {
if (bytes == null || bytes.length == 0) {
return;
}
Request request = RequestFactory.createByteArrayRequest();
request.setRequestData(bytes);
sendRequest(request);
}
/**
* 发送 ByteBuffer 数据
*/
public void send(ByteBuffer byteBuffer) {
if (byteBuffer == null) {
return;
}
Request request = RequestFactory.createByteBufferRequest();
request.setRequestData(byteBuffer);
sendRequest(request);
}
/**
* 发送 Ping
*/
public void sendPing() {
sendRequest(RequestFactory.createPingRequest());
}
/**
* 发送 Pong
*/
public void sendPong() {
sendRequest(RequestFactory.createPongRequest());
}
/**
* 发送 Pong
*/
public void sendPong(PingFrame pingFrame) {
if (pingFrame == null) {
return;
}
Request request = RequestFactory.createPongRequest();
request.setRequestData(pingFrame);
sendRequest(request);
}
/**
* 发送 {@link Framedata}
*/
public void sendFrame(Framedata framedata) {
if (framedata == null) {
return;
}
Request request = RequestFactory.createFrameDataRequest();
request.setRequestData(framedata);
sendRequest(request);
}
/**
* 发送 {@link Framedata} 集合
*/
public void sendFrame(Collection frameData) {
if (frameData == null) {
return;
}
Request> request = RequestFactory.createCollectionFrameRequest();
request.setRequestData(frameData);
sendRequest(request);
}
/**
* 添加一个监听器，使用完成之后需要调用
* {@link #removeListener(SocketListener)} 方法移除监听器
*/
public WebSocketManager addListener(SocketListener listener) {
mDelivery.addListener(listener);
return this;
}
/**
* 移除一个监听器
*/
public WebSocketManager removeListener(SocketListener listener) {
mDelivery.removeListener(listener);
return this;
}
/**
* 获取配置类，
* 部分参数支持动态设定。
*/
public WebSocketSetting getSetting() {
return mSetting;
}
/**
* 彻底销毁该连接，销毁后改连接完全失效，
* 请勿使用其他方法。
*/
public void destroy() {
destroyed = true;
if (mWebSocket != null) {
mWebSocketEngine.destroyWebSocket(mWebSocket);
mWebSocketEngine = null;
mWebSocket = null;
}
if (mDelivery != null) {
if (!mDelivery.isEmpty()) {
mDelivery.clear();
}
mDelivery = null;
}
if (mReconnectManager != null) {
if (mReconnectManager.reconnecting()) {
mReconnectManager.stopReconnect();
}
mReconnectManager = null;
}
WebSocketHandler.clearDefaultWebSocket();
}
/**
* 重新连接一次,
* for {@link ReconnectManager}
*/
void reconnectOnce() {
if (destroyed) {
LogUtil.e(TAG, "This WebSocketManager is destroyed!");
return;
}
if (mWebSocket.getConnectState() == 0) {
mWebSocketEngine.connect(mWebSocket, mSocketWrapperListener);
} else {
if (mReconnectManager != null) {
mReconnectManager.onConnected();
}
LogUtil.e(TAG, "WebSocket 已连接，请勿重试。");
}
}
/**
* 发送数据
*/
private void sendRequest(Request request) {
if (destroyed) {
LogUtil.e(TAG, "This WebSocketManager is destroyed!");
return;
}
LogUtil.d(TAG, "mWebSocketEngine.sendRequest");
mWebSocketEngine.sendRequest(mWebSocket, request, mSocketWrapperListener);
}
/**
* 获取默认的重连器
*/
private ReconnectManager getDefaultReconnectManager() {
return new DefaultReconnectManager(this, new ReconnectManager.OnConnectListener() {
@Override
public void onConnected() {
LogUtil.i(TAG, "重连成功");
// mSetting.getResponseDispatcher()
// .onConnected(mDelivery);
}
@Override
public void onDisconnect() {
LogUtil.i(TAG, "重连失败");
mSetting.getResponseDispatcher()
.onDisconnect(mDelivery);
}
});
}
/**
* 获取监听器
*/
private SocketWrapperListener getSocketWrapperListener() {
return new SocketWrapperListener() {
@Override
public void onConnected() {
if (mReconnectManager != null) {
mReconnectManager.onConnected();
}
mSetting.getResponseDispatcher()
.onConnected(mDelivery);
}
@Override
public void onConnectFailed(Throwable e) {
//if reconnecting,interrupt this event for ReconnectManager.
if (mReconnectManager != null &&
mReconnectManager.reconnecting()) {
mReconnectManager.onConnectError(e);
}
mSetting.getResponseDispatcher()
.onConnectFailed(e, mDelivery);
}
@Override
public void onDisconnect() {
LogUtil.i(TAG, "onDisconnect 开始重连");
// mSetting.getResponseDispatcher()
// .onDisconnect(mDelivery);
if (mReconnectManager != null &&
mReconnectManager.reconnecting()) {
if (disconnect) {
mSetting.getResponseDispatcher()
.onDisconnect(mDelivery);
} else {
mReconnectManager.onConnectError(null);
}
} else {
if (!disconnect) {
if (mReconnectManager == null) {
mReconnectManager = getDefaultReconnectManager();
}
mReconnectManager.onConnectError(null);
mReconnectManager.startReconnect();
}
}
}
@Override
public void onSendDataError(Request request, int type, Throwable tr) {
ErrorResponse errorResponse = ResponseFactory.createErrorResponse();
errorResponse.init(request, type, tr);
if (mSetting.processDataOnBackground()) {
mResponseProcessEngine
.onSendDataError(errorResponse,
mSetting.getResponseDispatcher(),
mDelivery);
} else {
mSetting.getResponseDispatcher().onSendDataError(errorResponse, mDelivery);
}
if (!disconnect && type == ErrorResponse.ERROR_NO_CONNECT) {
LogUtil.e(TAG, "数据发送失败，网络未连接，开始重连。。。");
reconnect();
}
}
@Override
public void onMessage(Response message) {
if (mSetting.processDataOnBackground()) {
mResponseProcessEngine
.onMessageReceive(message,
mSetting.getResponseDispatcher(),
mDelivery);
} else {
message.onResponse(mSetting.getResponseDispatcher(), mDelivery);
}
}
};
}
/**
* 监听网络变化广播，网络变化时自动重连
*/
public class NetworkChangedReceiver extends BroadcastReceiver {
private static final String TAG = "WSNetworkReceiver";
public NetworkChangedReceiver() {
}
@Override
public void onReceive(Context context, Intent intent) {
if (ConnectivityManager.CONNECTIVITY_ACTION.equals(intent.getAction())) {
ConnectivityManager manager = (ConnectivityManager) context
.getSystemService(Context.CONNECTIVITY_SERVICE);
if (manager == null) return;
try {
if (PermissionUtil.checkPermission(context, Manifest.permission.ACCESS_NETWORK_STATE)) {
NetworkInfo activeNetwork = manager.getActiveNetworkInfo();
if (activeNetwork != null) {
if (activeNetwork.isConnected()) {
if (activeNetwork.getType() == ConnectivityManager.TYPE_WIFI) {
LogUtil.i(TAG, "网络连接发生变化，当前WiFi连接可用，正在尝试重连。");
} else if (activeNetwork.getType() == ConnectivityManager.TYPE_MOBILE) {
LogUtil.i(TAG, "网络连接发生变化，当前移动连接可用，正在尝试重连。");
}
if (WebSocketHandler.getDefault() != null) {
if (WebSocketHandler.getDefault().getSetting().reconnectWithNetworkChanged()) {
WebSocketHandler.getDefault().reconnect();
}
}
if (!WebSocketHandler.getAllWebSocket().isEmpty()) {
Map webSocketManagerMap = WebSocketHandler.getAllWebSocket();
for (String key : webSocketManagerMap.keySet()) {
WebSocketManager item = webSocketManagerMap.get(key);
if (item != null && item.getSetting().reconnectWithNetworkChanged()) {
item.reconnect();
}
}
}
} else {
LogUtil.i(TAG, "当前没有可用网络");
}
}else{
LogUtil.i(TAG, "当前网络断开");
// EventBus.getDefault().post(new NetworkChangedReceiverNotify(false));
}
}
} catch (Exception e) {
LogUtil.e(TAG, "网络状态获取错误", e);
}
}
}
}
3.关于弱网的环境下的一些情况：
一、发送消息失败或收取消息失败（让用户在ui交互上，自己点击重新发送或者下拉刷新通过http接口拉取最新服务器数据，内部封装好重新连接socket的逻辑）
二、手机有弱网情况，房间内很多用户同时向服务器发送同种类型消息，比如：准备协议。这时，弱网的手机，发送的消息给服务器，服务器可能收到了，但是因为网络环境不稳定，客户端不一定能收到这条对应回来的消息。发送的数据，一定会有与之配对服务器返回的数据。但是在一些特定的场景下，可能服务器回来的消息，客户端这边收到不到。比如：弱网的环境，会出现丢包、丢数据的情况。
4.关于客户端断开 socket 的时机和策略
断开分为几种情况：
一、客户端自己主动离开房间，正常断开；
二、客户端杀掉APP后台进程，这时服务器依赖于心跳，30s没有收到客户端的心跳请求，会把客户端的连接状态断开；
5.关于消息分发器
接受到的数据，需要通过消息分发器来分发。先进入该类中处理，处理完再发送到下游。
public class AppResponseDispatcher extends SimpleDispatcher {
/**
* JSON 数据格式错误
*/
public static final int JSON_ERROR = 11;
/**
* code 码错误
*/
public static final int CODE_ERROR = 12;
@Override
public void onMessage(String message, ResponseDelivery delivery) {
try {
Gson gson = new Gson();
BaseProtocol response = gson.fromJson(message,BaseProtocol.class);
//op在1000与2000之间的协议，是客户端和服务器之间约定的有效op协议
if (response.op >= 1000 && response.op < 2000) {
delivery.onMessage(message, response);
} else {
ErrorResponse errorResponse = ResponseFactory.createErrorResponse();
errorResponse.setErrorCode(CODE_ERROR);
Response textResponse = ResponseFactory.createTextResponse();
textResponse.setResponseData(message);
errorResponse.setResponseData(textResponse);
errorResponse.setReserved(response);
onSendDataError(errorResponse, delivery);
}
} catch (Exception e) {
ErrorResponse errorResponse = ResponseFactory.createErrorResponse();
Response textResponse = ResponseFactory.createTextResponse();
textResponse.setResponseData(message);
errorResponse.setResponseData(textResponse);
errorResponse.setErrorCode(JSON_ERROR);
errorResponse.setCause(e);
onSendDataError(errorResponse, delivery);
}
}
/**
* 统一处理错误信息，
* 界面上可使用 ErrorResponse#getDescription() 来当做提示语
*/
@Override
public void onSendDataError(ErrorResponse error, ResponseDelivery delivery) {
switch (error.getErrorCode()) {
case ErrorResponse.ERROR_NO_CONNECT:
error.setDescription("网络错误");
break;
case ErrorResponse.ERROR_UN_INIT:
error.setDescription("连接未初始化");
break;
case ErrorResponse.ERROR_UNKNOWN:
error.setDescription("未知错误");
break;
case JSON_ERROR:
error.setDescription("数据格式异常");
break;
case CODE_ERROR:
error.setDescription("响应码错误");
break;
}
delivery.onSendDataError(error);
}
}
/**
* 一个简单的 WebSocket 消息分发器，实现了 {@link IResponseDispatcher} 接口，
* 因为 IResponseDispatcher 中的方法比较多，所以在此提供了一个简单版本，
* 只需要实现其中主要的几个方法即可。
*/
public abstract class SimpleDispatcher implements IResponseDispatcher {
@Override
public void onConnected(ResponseDelivery delivery) {
delivery.onConnected();
}
@Override
public void onConnectFailed(Throwable cause, ResponseDelivery delivery) {
delivery.onConnectFailed(cause);
}
@Override
public void onDisconnect(ResponseDelivery delivery) {
if(delivery != null){
delivery.onDisconnect();
}
}
@Override
public void onMessage(ByteBuffer byteBuffer, ResponseDelivery delivery) {
delivery.onMessage(byteBuffer, null);
}
@Override
public void onPing(Framedata framedata, ResponseDelivery delivery) {
delivery.onPing(framedata);
}
@Override
public void onPong(Framedata framedata, ResponseDelivery delivery) {
delivery.onPong(framedata);
}
}
/**
* 消息发射器接口
*/
public interface ResponseDelivery extends SocketListener {
void addListener(SocketListener listener);
void removeListener(SocketListener listener);
void clear();
boolean isEmpty();
}
/**
* WebSocket 监听器
*/
public interface SocketListener {
/**
* 连接成功
*/
void onConnected();
/**
* 连接失败
*/
void onConnectFailed(Throwable e);
/**
* 连接断开
*/
void onDisconnect();
/**
* 数据发送失败
*
* @param errorResponse 失败响应
*/
void onSendDataError(ErrorResponse errorResponse);
/**
* 接收到文本消息
*
* @param message 文本消息
* @param data 用户可将数据转成对应的泛型类型，可能为空，具体看用户在 {@link com.im.websocket.websocketlib.dispatcher.IResponseDispatcher}
* 中的实现，默认为空
* @param IResponseDispatcher 中转换的泛型类型
*/
void onMessage(String message, T data);
/**
* 接收到二进制消息
*
* @param bytes 二进制消息
* @param data 用户可将数据转成对应的泛型类型，可能为空，具体看用户在 {@link com.im.websocket.websocketlib.dispatcher.IResponseDispatcher}
* 中的实现，默认为空
* @param IResponseDispatcher 中转换的泛型类型
*/
void onMessage(ByteBuffer bytes, T data);
/**
* 接收到 ping
*/
void onPing(Framedata framedata);
/**
* 接收到 pong
*/
void onPong(Framedata framedata);
}
6.关于用到的相关源码部分
connectBlocking：WebSocketClient 的 connectBlocking() 会多出一个等待操作，会先连接再发送，否则未连接发送会报错。里面有用到 countDownLatch 这个类使一个线程等待其他线程各自执行完毕后再执行。
在 Java 的 原生 Socket 类里：
public class Socket implements java.io.Closeable {
/**
* Connects this socket to the server with a specified timeout value.
* A timeout of zero is interpreted as an infinite timeout. The connection
* will then block until established or an error occurs.
*
* @param endpoint the {@code SocketAddress}
* @param timeout the timeout value to be used in milliseconds.
* @throws IOException if an error occurs during the connection
* @throws SocketTimeoutException if timeout expires before connecting
* @throws java.nio.channels.IllegalBlockingModeException
* if this socket has an associated channel,
* and the channel is in non-blocking mode
* @throws IllegalArgumentException if endpoint is null or is a
* SocketAddress subclass not supported by this socket
* @since 1.4
* @spec JSR-51
*/
public void connect(SocketAddress endpoint, int timeout) throws IOException {
if (endpoint == null)
throw new IllegalArgumentException("connect: The address can't be null");
if (timeout < 0)
throw new IllegalArgumentException("connect: timeout can't be negative");
if (isClosed())
throw new SocketException("Socket is closed");
if (!oldImpl && isConnected())
throw new SocketException("already connected");
if (!(endpoint instanceof InetSocketAddress))
throw new IllegalArgumentException("Unsupported address type");
InetSocketAddress epoint = (InetSocketAddress) endpoint;
InetAddress addr = epoint.getAddress ();
int port = epoint.getPort();
checkAddress(addr, "connect");
SecurityManager security = System.getSecurityManager();
if (security != null) {
if (epoint.isUnresolved())
security.checkConnect(epoint.getHostName(), port);
else
security.checkConnect(addr.getHostAddress(), port);
}
if (!created)
createImpl(true);
if (!oldImpl)
impl.connect(epoint, timeout);
else if (timeout == 0) {
if (epoint.isUnresolved())
impl.connect(addr.getHostName(), port);
else
impl.connect(addr, port);
} else
throw new UnsupportedOperationException("SocketImpl.connect(addr, timeout)");
connected = true;
/*
* If the socket was not bound before the connect, it is now because
* the kernel will have picked an ephemeral port & a local address
*/
bound = true;
}
}
关于 WebSocketImpl 里的BlockingQueue。BlockingQueue即阻塞队列，它是基于ReentrantLock。
在Java中，BlockingQueue是一个接口，它的实现类有ArrayBlockingQueue、DelayQueue、 LinkedBlockingDeque、LinkedBlockingQueue、PriorityBlockingQueue、SynchronousQueue等，它们的区别主要体现在存储结构上或对元素操作上的不同，但是对于take与put操作的原理，却是类似的。
/**
* 表示单个WebSocketImpl连接的一端（客户端或服务器）。处理“握手”阶段，然后允许通过基于
* 事件的模型,轻松发送文本框架和接收框架。
*/
public class WebSocketImpl implements WebSocket {
/**
* Queue of buffers that need to be sent to the client.
*/
public final BlockingQueue outQueue;
/**
* Queue of buffers that need to be processed
*/
public final BlockingQueue inQueue;
/**
* creates a websocket with client role
*
* @param listener The listener for this instance
* @param draft The draft which should be used
*/
public WebSocketImpl( WebSocketListener listener, Draft draft ) {
...
this.outQueue = new LinkedBlockingQueue();
inQueue = new LinkedBlockingQueue();
...
}
}
LinkedBlockingQueue中维持两把锁，一把锁用于入队，一把锁用于出队，这也就意味着，同一时刻，只能有一个线程执行入队，其余执行入队的线程将会被阻塞；同时，可以有另一个线程执行出队，其余执行出队的线程将会被阻塞。换句话说，虽然入队和出队两个操作同时均只能有一个线程操作，但是可以一个入队线程和一个出队线程共同执行，也就意味着可能同时有两个线程在操作队列，那么为了维持线程安全，LinkedBlockingQueue使用一个AtomicInterger类型的变量表示当前队列中含有的元素个数，所以可以确保两个线程之间操作底层队列是线程安全的。
关于握手协议
在 WebSocketClient 类下：
/**
* 创建握手并将其发送到另一个端点
* @throws InvalidHandshakeException a invalid handshake was created
*/
private void sendHandshake() throws InvalidHandshakeException {
String path;
String part1 = uri.getRawPath();
String part2 = uri.getRawQuery();
if( part1 == null || part1.length() == 0 )
path = "/";
else
path = part1;
if( part2 != null )
path += '?' + part2;
int port = getPort();
String host = uri.getHost() + (
(port != WebSocketImpl.DEFAULT_PORT && port != WebSocketImpl.DEFAULT_WSS_PORT)
? ":" + port
: "" );
HandshakeImpl1Client handshake = new HandshakeImpl1Client();
handshake.setResourceDescriptor( path );
handshake.put( "Host", host );
if( headers != null ) {
for( Map.Entry kv : headers.entrySet() ) {
handshake.put( kv.getKey(), kv.getValue() );
}
}
engine.startHandshake( handshake );
}
/**
* 由WebSocketClient和WebSocketServer实现。 WebSocket调用其中的方法。几乎每个方法都采
* 用第一个参数conn，该参数代表相应事件的来源。
*/
public interface WebSocketListener {
/**
* Called on the server side when the socket connection is first established, and the WebSocket
* handshake has been received. This method allows to deny connections based on the received handshake.
* By default this method only requires protocol compliance.
*
* @param conn
* The WebSocket related to this event
* @param draft
* The protocol draft the client uses to connect
* @param request
* The opening http message send by the client. Can be used to access additional fields like cookies.
* @return Returns an incomplete handshake containing all optional fields
* @throws InvalidDataException
* Throwing this exception will cause this handshake to be rejected
*/
ServerHandshakeBuilder onWebsocketHandshakeReceivedAsServer( WebSocket conn, Draft draft, ClientHandshake request ) throws InvalidDataException;
/**
* Called on the client side when the socket connection is first established, and the WebSocketImpl
* handshake response has been received.
*
* @param conn
* The WebSocket related to this event
* @param request
* The handshake initially send out to the server by this websocket.
* @param response
* The handshake the server sent in response to the request.
* @throws InvalidDataException
* Allows the client to reject the connection with the server in respect of its handshake response.
*/
void onWebsocketHandshakeReceivedAsClient( WebSocket conn, ClientHandshake request, ServerHandshake response ) throws InvalidDataException;
/**
* Called on the client side when the socket connection is first established, and the WebSocketImpl
* handshake has just been sent.
*
* @param conn
* The WebSocket related to this event
* @param request
* The handshake sent to the server by this websocket
* @throws InvalidDataException
* Allows the client to stop the connection from progressing
*/
void onWebsocketHandshakeSentAsClient( WebSocket conn, ClientHandshake request ) throws InvalidDataException;
/**
* Called when an entire text frame has been received. Do whatever you want
* here...
*
* @param conn
* The WebSocket instance this event is occurring on.
* @param message
* The UTF-8 decoded message that was received.
*/
void onWebsocketMessage( WebSocket conn, String message );
/**
* Called when an entire binary frame has been received. Do whatever you want
* here...
*
* @param conn
* The WebSocket instance this event is occurring on.
* @param blob
* The binary message that was received.
*/
void onWebsocketMessage( WebSocket conn, ByteBuffer blob );
/**
* Called after onHandshakeReceived returns true.
* Indicates that a complete WebSocket connection has been established,
* and we are ready to send/receive data.
*
* @param conn The WebSocket instance this event is occuring on.
* @param d The handshake of the websocket instance
*/
void onWebsocketOpen( WebSocket conn, Handshakedata d );
/**
* Called after WebSocket#close is explicity called, or when the
* other end of the WebSocket connection is closed.
*
* @param ws The WebSocket instance this event is occuring on.
* @param code The codes can be looked up here: {@link CloseFrame}
* @param reason Additional information string
* @param remote Returns whether or not the closing of the connection was initiated by the remote host.
*/
void onWebsocketClose( WebSocket ws, int code, String reason, boolean remote );
/** Called as soon as no further frames are accepted
*
* @param ws The WebSocket instance this event is occuring on.
* @param code The codes can be looked up here: {@link CloseFrame}
* @param reason Additional information string
* @param remote Returns whether or not the closing of the connection was initiated by the remote host.
*/
void onWebsocketClosing( WebSocket ws, int code, String reason, boolean remote );
/** send when this peer sends a close handshake
*
* @param ws The WebSocket instance this event is occuring on.
* @param code The codes can be looked up here: {@link CloseFrame}
* @param reason Additional information string
*/
void onWebsocketCloseInitiated( WebSocket ws, int code, String reason );
/**
* Called if an exception worth noting occurred.
* If an error causes the connection to fail onClose will be called additionally afterwards.
*
* @param conn The WebSocket instance this event is occuring on.
* @param ex
* The exception that occurred.
* Might be null if the exception is not related to any specific connection. For example if the server port could not be bound.
*/
void onWebsocketError( WebSocket conn, Exception ex );
/**
* Called a ping frame has been received.
* This method must send a corresponding pong by itself.
*
* @param conn The WebSocket instance this event is occuring on.
* @param f The ping frame. Control frames may contain payload.
*/
void onWebsocketPing( WebSocket conn, Framedata f );
/**
* Called when a pong frame is received.
*
* @param conn The WebSocket instance this event is occuring on.
* @param f The pong frame. Control frames may contain payload.
**/
void onWebsocketPong( WebSocket conn, Framedata f );
/** This method is used to inform the selector thread that there is data queued to be written to the socket.
* @param conn The WebSocket instance this event is occuring on.
*/
void onWriteDemand( WebSocket conn );
/**
* @see WebSocket#getLocalSocketAddress()
*
* @param conn The WebSocket instance this event is occuring on.
* @return Returns the address of the endpoint this socket is bound to.
*/
InetSocketAddress getLocalSocketAddress( WebSocket conn );
/**
* @see WebSocket#getRemoteSocketAddress()
*
* @param conn The WebSocket instance this event is occuring on.
* @return Returns the address of the endpoint this socket is connected to, or{@code null} if it is unconnected.
*/
InetSocketAddress getRemoteSocketAddress( WebSocket conn );
}
WebSocketHandler 是个很重要的概念，我们无论是 WebSocket 的初始化、创建连接、断开连接、数据收发等等都要使用它来实现。
/**
* WebSocket 用户控制句柄
*/
public class WebSocketHandler {
private final static String TAG = "WebSocketHandler";
/**
* 消息发送引擎
*/
private static WebSocketEngine webSocketEngine;
/**
* 消息处理引擎
*/
private static ResponseProcessEngine responseProcessEngine;
/**
* 默认的 WebSocket 连接
*/
private static WebSocketManager defaultWebSocket;
/**
* 对 {@link #mWebSocketMap} 操作时的锁
*/
private static final Object WS_MAP_BLOCK = new HashMap<>();
/**
* 通过 Map 存储 WSM 对象，以此支持多个连接
*/
private static Map mWebSocketMap;
private static Logable mLog;
/**
* 初始化默认的 WebSocket 连接
*
* @param setting 该连接的相关设置参数
*/
public static WebSocketManager init(WebSocketSetting setting) {
defaultWebSocket = null;
synchronized (WebSocketHandler.class) {
if (webSocketEngine == null) {
webSocketEngine = new WebSocketEngine();
}
if (responseProcessEngine == null) {
responseProcessEngine = new ResponseProcessEngine();
}
if (defaultWebSocket == null) {
defaultWebSocket = new WebSocketManager(setting,
webSocketEngine,
responseProcessEngine);
}
}
return defaultWebSocket;
}
public static void clearDefaultWebSocket(){
defaultWebSocket = null;
}
/**
* 通过唯一标识符新建一个 WebSocket 连接
*
* @param key 该 WebSocketManager 的唯一标识符，
* 后面需要通过这个 key 来获取到对应的 WebSocketManager
* @param setting 该连接的相关设置参数
*/
public static WebSocketManager initGeneralWebSocket(String key, WebSocketSetting setting) {
checkEngineNullAndInit();
checkWebSocketMapNullAndInit();
synchronized (WS_MAP_BLOCK) {
if (mWebSocketMap.containsKey(key)) {
LogUtil.e(TAG, "WebSocketManager exists!do not start again!");
return mWebSocketMap.get(key);
} else {
WebSocketManager wsm = new WebSocketManager(setting,
webSocketEngine,
responseProcessEngine);
mWebSocketMap.put(key, wsm);
return wsm;
}
}
}
/**
* 获取默认的 WebSocket 连接，
* 调用此方法之前需要先调用 {@link #init(WebSocketSetting)} 方法初始化
*
* @return 返回一个 {@link WebSocketManager} 实例
*/
public static WebSocketManager getDefault() {
return defaultWebSocket;
}
/**
* 获取 WebSocketManager 对象
*
* @param key 该 WebSocketManager 的 key
* @return 可能为空，代表该 WebSocketManager 对象不存在或已移除
*/
public static WebSocketManager getWebSocket(String key) {
checkWebSocketMapNullAndInit();
if (mWebSocketMap.containsKey(key)) {
return mWebSocketMap.get(key);
} else {
return null;
}
}
/**
* 获取所有 WebSocketManager（defaultWebSocketManager 除外）
*/
public static Map getAllWebSocket() {
checkWebSocketMapNullAndInit();
return mWebSocketMap;
}
/**
* 移除一个 WebSocketManager 对象
*
* @param key 该 WebSocketManager 的 key
* @return 返回移除的 WebSocketManager，可能为空
*/
public static WebSocketManager removeWebSocket(String key) {
checkWebSocketMapNullAndInit();
if (mWebSocketMap.containsKey(key)) {
WebSocketManager removed = mWebSocketMap.get(key);
synchronized (WS_MAP_BLOCK) {
mWebSocketMap.remove(key);
}
return removed;
} else {
return null;
}
}
/**
* 注册网络变化监听广播，网络由不可用变为可用时会重新连接 WebSocket
*
* @param context 此处应该使用 ApplicationContext，避免内存泄漏以及其它异常。
*/
public static void registerNetworkChangedReceiver(Context context) {
if (PermissionUtil.checkPermission(context, Manifest.permission.ACCESS_NETWORK_STATE)) {
try {
IntentFilter filter = new IntentFilter();
filter.addAction(ConnectivityManager.CONNECTIVITY_ACTION);
context.registerReceiver(new NetworkChangedReceiver(), filter);
} catch (Exception e) {
LogUtil.e(TAG, "网络监听广播注册失败：", e);
}
} else {
LogUtil.e(TAG, "未获取到网络状态权限，广播监听器无法注册");
}
}
/**
* 初始化引擎
*/
private static void checkEngineNullAndInit() {
if (webSocketEngine == null || responseProcessEngine == null) {
synchronized (WebSocketHandler.class) {
if (webSocketEngine == null) {
webSocketEngine = new WebSocketEngine();
}
if (responseProcessEngine == null) {
responseProcessEngine = new ResponseProcessEngine();
}
}
}
}
/**
* 初始化 mWebSocketMap
*/
private static void checkWebSocketMapNullAndInit() {
if (mWebSocketMap == null) {
synchronized (WS_MAP_BLOCK) {
if (mWebSocketMap == null) {
mWebSocketMap = new HashMap<>();
}
}
}
}
/**
* 设置打印日志实现类，设置完成后内部运行日志会通过设置的实现类打印。
* 需实现 {@link Logable} 接口
*/
public static void setLogable(Logable logable) {
mLog = logable;
}
public static Logable getLogable() {
if (mLog == null) {
mLog = new LogImpl();
}
return mLog;
}
}