在Tomcat 7.0.54上本地部署应用程序，然后连接到ws：// localhost：8080 / request / subscription / messenger / xxxx 一切正常。
但是当在远程服务器上部署为.war时（Tomcat 8.0.18 - websocket-api.jar在lib文件夹中）无法连接，让我们说 ws：//myshost.com：8080 / request / subscription / messenger / xxxx
FireBug输出中的FF“无法建立与服务器的连接” “NetworkError：404 Not Found - http://myshost.com:8080/request/subscription/messenger/xxxx”
JS ws-client代码：
var webSocket;
var messages = document.getElementById("messages");
var token = document.getElementById("token").value;
// var tokenTo = document.getElementById("token_to").value;
var subscrContext = document.getElementById("context").value;
var host = document.getElementById("host").value;
// var port = document.getElementById("port").value;
function openSocket(){
// Ensures only one connection is open at a time
if(webSocket !== undefined && webSocket.readyState !== WebSocket.CLOSED){
writeResponse("WebSocket is already opened.");
return;
}
// Create a new instance of the websocket
var wsUrl = "ws://"+host+":8080/request/subscription/"+subscrContext+"/"+token;
console.log(wsUrl);
webSocket = new WebSocket(wsUrl);
/**
* Binds functions to the listeners for the websocket.
*/
webSocket.onopen = function(event){
// For reasons I can't determine, onopen gets called twice
// and the first time event.data is undefined.
// Leave a comment if you know the answer.
if(event.data === undefined)
return;
writeResponse(event.data);
};
webSocket.onmessage = function(event){
// var json = JSON.parse(event.data);
writeResponse(event.data);
};
webSocket.onclose = function(event){
writeResponse(event.data);
};
}
/**
* Sends the value of the text input to the server
*/
function send(){
var text = document.getElementById("messageinput").value;
// var json = {
// 'action':'send_message',
// 'uid':123,
// 'text':text
// };
webSocket.send(text);
}
function closeSocket(){
webSocket.close();
}
function writeResponse(text){
messages.innerHTML += "<br/>" + text;
}
function clear() {
messages.innerHTML = '';
}
Java ws-server-endpoint code
@ServerEndpoint(value = "/subscription/{context}/{token}", encoders = {MessageEncoder.class}, decoders = {MessageDecoder.class})
public class SubscriptionServer implements Commons {
private Queries q;
// private ByteBuffer buff;
private int currentUserId;
private static final int
ERR_REQ_PARAM = 802;
// storing sessions for messenger
public static Map<Integer, Session> usersMessenger = new HashMap<>(),
// storing sessions for road
usersRoad = new HashMap<>();
public static Map<Integer, List<Integer>> userPosts = new HashMap<>();
private static final Map<Integer, String>
errUserMsg = new HashMap<>(),
errSysMsg = new HashMap<>();
private String token;
private final static String
CONTEXT_MESSENGER = "messenger",
CONTEXT_ROAD = "road";
@OnOpen
public void onOpen(@PathParam("context") String context,
@PathParam("token") String grossToken, Session sess) throws IOException,
ClassNotFoundException, SQLException, EncodeException, JSONException {
token = Helper.getToken(grossToken);
currentUserId = Helper.getUserId(grossToken);
Logger.log("open user: "+currentUserId);
// sess.getBasicRemote().sendObject(
// new JSONObject().put("token", token).put("uid", currentUserId));
q = new Queries();
if (q.checkToken(token, currentUserId) > 0) {
subscribeUser(currentUserId, sess, context);
sess.getBasicRemote().sendObject(new JSONObject()
.put("token", token).put("user_id", currentUserId));
} else {
sess.getBasicRemote().sendObject(Helper.getErrorMessage(ERR_TOKEN,
"Этот аккаунт используется с другого устройства.", "Этот аккаунт используется с другого устройства."));
sess.close();
}
// System.out.println("User with id: " + sess.getId() + " has been connected!");
}
@OnMessage
public void onMessage(@PathParam("context") String context, JSONObject json, Session sess) throws IOException, JSONException, EncodeException {
// System.out.println("User with sid: "+sess.getId()+" sending msg:"+json.getString("text"));
// JSONObject json = new JSONObject(msg);
// Logger.log(json.toString());
// sess.getBasicRemote().sendText("Received message:"+json);
// ping - pong
if (json.has("ping") && json.getInt("ping")==1) {
sess.getBasicRemote().sendObject(new JSONObject().put("pong", 1));
return;
}
switch (context) {
case CONTEXT_MESSENGER:
sendMessageEvent(json.getInt("user_id"), json, sess);
break;
case CONTEXT_ROAD:
sendRoadEvents(currentUserId, json, sess);
break;
}
// String message = "Received message int bytes: "+msg;
//
// byte[] bytes = message.getBytes("UTF-16BE");
//
// buff = ByteBuffer.allocate(bytes.length+1);
//
// buff.put(bytes);
//
// sess.getBasicRemote().sendBinary(buff);
}
@OnClose
public void onClose(Session sess, CloseReason reason, @PathParam("context") String context)
throws IOException, JSONException, EncodeException {
unsubscribeUser(currentUserId, context);
sess.getBasicRemote().sendObject(Helper.getSuccess(new JSONObject().put("reason", "ServerEndpoint timeout")));
}
private void subscribeUser(int userId, Session sess, String context) {
Logger.log("subscribe user: "+userId);
SubscriptionQueries subscrQueries = new SubscriptionQueries();
try {
// check tmp memory table - send if contains some
List<String> jsonList = subscrQueries.getSubscriptionTmp(userId);
if (!jsonList.isEmpty()) {
sess.getBasicRemote().sendObject(new JSONObject().put("success", jsonList));
}
switch (context) {
case CONTEXT_MESSENGER:
usersMessenger.put(userId, sess);
sess.getBasicRemote().sendObject(Helper.getSuccess());
break;
case CONTEXT_ROAD:
usersRoad.put(userId, sess);
// int startIndex = (request.getParameter("start_index") == null) ? 0 : Integer.parseInt(request.getParameter("start_index"));
// int quantity = (request.getParameter("quantity") == null) ? 20 : Integer.parseInt(request.getParameter("quantity"));
// last 20 posts user sees when open road
int startIndex = 0;
int quantity = 20;
List<Integer> posts = subscrQueries.getUserPosts(startIndex, quantity);
userPosts.put(userId, posts);
sess.getBasicRemote().sendObject(Helper.getSuccess());
break;
}
} catch (ClassNotFoundException | SQLException | IOException | JSONException | EncodeException ex) {
Logger.log(Arrays.toString(ex.getStackTrace()), "error.log");
Logger.log(ex.getMessage(), "error.log");
}
}
private void unsubscribeUser(int userId, String context) throws JSONException, IOException, EncodeException {
Session sess;
switch (context) {
case CONTEXT_MESSENGER:
sess = usersMessenger.remove(userId);
sess.getBasicRemote().sendObject(Helper.getSuccess());
break;
case CONTEXT_ROAD:
sess = usersRoad.remove(userId);
userPosts.remove(userId);
sess.getBasicRemote().sendObject(Helper.getSuccess());
break;
}
}
private void sendMessageEvent(int userId, JSONObject json, Session sess) throws IOException, EncodeException, JSONException {
if (usersMessenger.containsKey(userId)) {
Session userSess = usersMessenger.get(userId);
userSess.getBasicRemote().sendObject(json);
} else { // tmp memory tbl in DB
SubscriptionQueries subscrQueries = new SubscriptionQueries();
try {
subscrQueries.setSubscriptionTmp(userId, json.toString());
} catch (ClassNotFoundException | SQLException ex) {
Logger.log(Arrays.toString(ex.getStackTrace()), "error.log");
Logger.log(ex.getMessage(), "error.log");
}
}
sess.getBasicRemote().sendObject(Helper.getSuccess());
}
private void sendRoadEvents(int currentUserId, JSONObject json, Session sess) throws JSONException, IOException, EncodeException {
// send to all users online, that where subscribed on these (say 20 last) posts
// likes, comments, deletes, comment responses
int userId;
Session userSess;
if (json.isNull("post_id")) {
sess.getBasicRemote().sendObject(Helper.getErrorMessage(ERR_REQ_PARAM,
"Нет обязательного параметра post_id", "Нет обязательного параметра post_id"));
return;
}
// sess.getBasicRemote().sendObject(new JSONObject().put("User Roads: ", usersRoad));
//
// sess.getBasicRemote().sendObject(new JSONObject().put("Users posts: ", userPosts));
for (Entry<Integer, Session> user : usersRoad.entrySet()) {
userId = user.getKey();
userSess = user.getValue();
// ensure - not equals to this user
if (currentUserId != userId && userPosts.containsKey(userId)) {
List<Integer> posts = userPosts.get(userId);
sess.getBasicRemote().sendObject(new JSONObject().put("Users posts: ", posts));
if (!posts.isEmpty() && posts.contains(json.getInt("post_id"))) {
userSess.getBasicRemote().sendObject(json);
}
}
}
// success after all
sess.getBasicRemote().sendObject(Helper.getSuccess());
}
private void setErrors() {
errSysMsg.put(ERR_REQ_PARAM, "Нет обязательного параметра");
errUserMsg.put(ERR_REQ_PARAM, "Нет обязательного параметра");
}
}
服务器正在100％运行 - 使用已经在web.xml中定义的Servlet的其他上下文的http请求多次检查 - 一切都是标准的，每个请求都在工作。
答案 0 :(得分：2)
答案很简单，应该是：
1）扩展HttpServlet
2）覆盖doGet方法以使用参数
接收GET需要获取WebSocket握手和升级标头。
PS但是在localhost上没有HttpServlet和doGet就可以了，因为它是在localhost上打开的同一台机器和socket服务器（比如在端口8080上）不需要通过http握手，这个东西很难确定 - 我希望对某人有所帮助。