Java WebSocket OnMessage方法未触发

Question

我正在尝试仅针对服务器和客户端（不允许使用Javascript）以及WebSocket使用JavaEE构建基于JavaEE网络的聊天应用程序。

我已经成功建立了到服务器的连接（借助于网上的教程），但是，在发送消息时，什么也没有发生，换句话说，OnMessage方法没有触发。作为WebSockets的新手，我不能为做错的事情而烦恼。

这是代码

服务器

import static java.lang.String.format;

import java.io.IOException;
import java.util.Collections;
import java.util.HashSet;
import java.util.Set;

import javax.websocket.EncodeException;
import javax.websocket.OnClose;
import javax.websocket.OnMessage;
import javax.websocket.OnOpen;
import javax.websocket.Session;

import server.MessageDecoder;
import server.MessageEncoder;
import entities.ApplicationUser;
import entities.Message;

@javax.websocket.server.ServerEndpoint(value = "/chat", encoders = MessageEncoder.class, decoders = MessageDecoder.class)
public class ServerEndpoint {

    static Set<Session> sessions = Collections.synchronizedSet(new HashSet<Session>());

    @OnOpen
    public void onOpen(Session session) {
        System.out.println(format("%s joined the chat room.", session.getId()));
        sessions.add(session);
    }

    @OnMessage
    public synchronized void onMessage(Session session, Message message) throws IOException, EncodeException {
        System.out.println("Here i am 0 ");
        ApplicationUser user = (ApplicationUser) session.getUserProperties().get("userSender");
        if (user == null) {
            session.getUserProperties().put("userSender", message.getSender());
            session.getUserProperties().put("userReceiver", message.getReceiver());
        }

        System.out.println("Here i am 1 ");
        System.out.println(format("[%s:%s] %s", session.getId(), message.getDateSent(), message.getMessage()));
        System.out.println("Here i am 2 ");

        sendMessageToOne(message, session, message.getReceiver().getSessionId());
    }

    public void sendMessageToOne(Message message, Session session, String strToSessionId) {
        for (Session s : sessions) {
            if (s.isOpen()) {
                try {
                    if (s.getId().equals(strToSessionId))
                    try {
                        System.out.println("Here i am 3 ");
                        s.getBasicRemote().sendObject(message);
                        System.out.println("Here i am 4 ");
                    } catch (EncodeException e) {
                        e.printStackTrace();
                    }

                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
     }

    @OnClose
    public void onClose(Session session) throws IOException, EncodeException {
        System.out.println(format("%s left the chat room.", session.getId()));
        sessions.remove(session);
        // notify peers about leaving the chat room
        for (Session peer : sessions) {
            Message chatMessage = new Message();
            //chatMessage.setSender("Server");
            //chatMessage.setContent(format("%s left the chat room.", (String) session.getUserProperties().get("user")));
            //chatMessage.setReceived(new Date());
            peer.getBasicRemote().sendObject(chatMessage);
        }
    }

}

消息编码器

import util.JsonUtil;
import Message;

import javax.websocket.EncodeException;
import javax.websocket.Encoder;
import javax.websocket.EndpointConfig;

public class MessageEncoder implements Encoder.Text<Message> {

    @Override
    public void init(final EndpointConfig config) {
    }

    @Override
    public void destroy() {
    }

    @Override
    public String encode(final Message message) throws EncodeException {
        return JsonUtil.formatMessage(message);
    }

}

消息解码器

import javax.json.Json;
import javax.json.JsonObject;
import javax.websocket.DecodeException;
import javax.websocket.Decoder;
import javax.websocket.EndpointConfig;

import org.joda.time.DateTime;

import entities.ApplicationUser;
import entities.Message;

import java.io.StringReader;

public class MessageDecoder implements Decoder.Text<Message> {

    @Override
    public void init(final EndpointConfig config) {
    }

    @Override
    public void destroy() {
    }

    @Override
    public Message decode(final String textMessage) throws DecodeException {
        Message chatMessage = new Message();
        JsonObject obj = Json.createReader(new StringReader(textMessage))
                .readObject();
        chatMessage.setMessage(obj.getString("message"));
        chatMessage.setSender(new ApplicationUser(Integer.parseInt(obj.getJsonObject("sender").getString("id")), 
                                                    obj.getJsonObject("sender").getString("email"), 
                                                    obj.getJsonObject("sender").getString("username")));
        chatMessage.setDateSent(new DateTime());
        return chatMessage;
    }

    @Override
    public boolean willDecode(final String s) {
        return true;
    }

}

客户端

import static java.lang.String.format;

import javax.websocket.OnMessage;
import javax.websocket.OnOpen;
import javax.websocket.Session;
import java.text.SimpleDateFormat;

import server.MessageDecoder;
import server.MessageEncoder;
import entities.Message;

@javax.websocket.ClientEndpoint(encoders = MessageEncoder.class, decoders = MessageDecoder.class)
public class ClientEndpoint {

    private SimpleDateFormat simpleDateFormat = new SimpleDateFormat();

    @OnOpen
    public void onOpen(Session session) {
        System.out.println(format("Connection established. session id: %s", session.getId()));
    }

    @OnMessage
    public void onMessage(Message message) {
        System.out.println("Client " + format("[%s:%s] %s", simpleDateFormat.format(message.getDateSent()), message.getSender(), message.getMessage()));
    }

}

选择用户与之聊天时在其中创建服务器的ChatBean

public String doGet(int destinationUserId) {
        System.out.println("Chat.doGet()");

        for (ApplicationUser user : userBean.getAllUsers()) {
            if(user.getId() == destinationUserId)
            {
                this.receiver = user;
                break;
            }
        }

        // Start the server
        org.glassfish.tyrus.server.Server server = new org.glassfish.tyrus.server.Server("localhost", 8025, "/ws", ServerEndpoint.class);

        try {
            server.start();
            System.out.println("I am here Right Now ");
        } catch (DeploymentException e) {
            throw new RuntimeException(e);
        } finally {
            //server.stop();
        }


        String roomName = Integer.toString(loginBean.getUser().getId()) + "0" + Integer.toString(destinationUserId);

        ClientManager client = ClientManager.createClient();
        //String message;

        // connect to server
        System.out.println("Welcome to Our Chat App!");

        try {
            session = client.connectToServer(ClientEndpoint.class, new URI(SERVER));
            // Set the user's session id
            loginBean.getUser().setSessionId(session.getId());

        } catch (DeploymentException | URISyntaxException e1) {
            e1.printStackTrace();
        }
        System.out.println("You are logged in as: " + session.getUserProperties().get("userSender"));       

        return displayChatThreads();
    }

public String displayChatThreads() {        
        return "/template/chat/chat.xhtml/?faces-redirect=true";
    }

单击“发送消息”按钮时调用的操作

public String doPost() {
        System.out.println("Chat.doPost()");


        System.out.println("Server ");

        // Send first message
        System.out.println("Here I am now 1 ");
        handleSendMessage();

        return displayChatThreads();
    }

private void handleSendMessage() {
    System.out.println("Message Sent " + msg);
    Message textMessage = new Message(msg, loginBean.getUser(), receiver, new DateTime(DateTime.now()));
        try {
            session.getBasicRemote().sendText(JsonUtil.formatMessage(textMessage));
            System.out.println("Message Sent " + session);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }