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java服务端基础知识

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package com.mes.util;

 

import java.io.IOException;

import java.util.Map;

import java.util.concurrent.ConcurrentHashMap;

 

import javax.websocket.OnClose;

import javax.websocket.OnError;

import javax.websocket.OnMessage;

import javax.websocket.OnOpen;

import javax.websocket.Session;

import javax.websocket.server.PathParam;

import javax.websocket.server.ServerEndpoint;

 

import org.springframework.stereotype.Component;

import org.springframework.stereotype.Service;

 

import com.google.gson.JsonObject;

 

import net.sf.json.JSONObject;

@ServerEndpoint("/webSocket/{username}")  

    public class WebSocket { 

        private static int onlineCount = 0; 

        private static Map clients = new ConcurrentHashMap (); 

        private Session session; 

        private String username; 

           

        @OnOpen 

        public void onOpen(@PathParam("username") String username, Session session) throws IOException { 

       

            this.username = username; 

            this.session = session; 

               

            addOnlineCount(); 

            clients.put(username, this);

            System.out.println("已连接");

        } 

       

        @OnClose 

        public void onClose() throws IOException { 

            clients.remove(username); 

            subOnlineCount(); 

        } 

       

        @OnMessage 

        public void onMessage(String message) throws IOException { 

       

            JSONObject jsonTo = JSONObject.fromObject(message); 

            String mes = (String) jsonTo.get("message");

             

            if (!jsonTo.get("To").equals("All")){ 

                sendMessageTo(mes, jsonTo.get("To").toString()); 

            }else{ 

                sendMessageAll("给所有人"); 

            } 

        } 

       

        @OnError 

        public void onError(Session session, Throwable error) { 

            error.printStackTrace(); 

        } 

       

        public void sendMessageTo(String message, String To) throws IOException { 

            // session.getBasicRemote().sendText(message); 

            //session.getAsyncRemote().sendText(message); 

            for (WebSocket item : clients.values()) { 

                if (item.username.equals(To) ) 

                    item.session.getAsyncRemote().sendText(message); 

            } 

        } 

           

        public void sendMessageAll(String message) throws IOException { 

            for (WebSocket item : clients.values()) { 

                item.session.getAsyncRemote().sendText(message); 

            } 

        } 

       

        public static synchronized int getOnlineCount() { 

            return onlineCount; 

        } 

       

        public static synchronized void addOnlineCount() { 

            WebSocket.onlineCount++; 

        } 

       

        public static synchronized void subOnlineCount() { 

            WebSocket.onlineCount--; 

        } 

       

        public static synchronized Map getClients() { 

            return clients; 

        }