WebSocket realize simple chat room

Front page:

Package com.uptop.websocket;
Import Com.alibaba.fastjson.JSON;

Import Com.uptop.entity.ResultVo;
Import javax.websocket.*;
Import Javax.websocket.server.ServerEndpoint;
Import java.io.IOException;

Import Java.util.concurrent.CopyOnWriteArraySet; /** * WebSocket Chat Room * * @author Administrator * @create 2018-02-05 15:17/@ServerEndpoint ("/wschat") public class W Ebsocketchat {//static variable, used to record the current number of online connections.
    It should be designed to be thread-safe.

    private static int onlinecount = 0; The thread-safe set of the concurrent package, which holds the corresponding Mywebsocket object for each client. To enable the server to communicate with a single client, you can use a map to store where key can be the user identity public static copyonwritearrayset<websocketchat> Websocketset = new C

    Opyonwritearrayset<websocketchat> ();

    A connection session with a client, which needs to be sent to the client to send the data private sessions; /** * Connection to establish a successful call method * * @param session Optional parameters. Session for a connection with a client, you need to send the data to the client/@OnOpen public void OnOpen {this.session = SE
        Ssion;     Websocketset.add (this); Add Addonlinecou in SetNT ();
        Online number plus 1//Send online number of people data resultvo Resultvo = new Resultvo ("0", This.onlinecount, "from server");
        Sendmsg (json.tojsonstring (Resultvo)); SYSTEM.OUT.PRINTLN ("There are new joins.")
    Current online number is "+ Getonlinecount ()");  /** * Connection Shutdown method of call/@OnClose public void OnClose () {websocketset.remove (this);           Deletes the Subonlinecount () from the set;
        Online number minus 1//Send online number of data resultvo Resultvo = new Resultvo ("0", This.onlinecount, "from server");
        Sendmsg (json.tojsonstring (Resultvo)); System.out.println ("There is a connection closed.")
    Current online number is "+ Getonlinecount ()"); 
    /** * The method called after receiving client messages * * @param message Client Sent messages * @param session Optional Parameters * * @OnMessage
        public void OnMessage (String messages, session sessions) {SYSTEM.OUT.PRINTLN ("Message from client: ' +");
        Encapsulates client messages Resultvo Resultvo = new Resultvo ("1", Message, "from client");
      String jsonstr = json.tojsonstring (RESULTVO);  Mass message for (Websocketchat Item:websocketset) {try {item.sendmessage (JSONSTR);
                catch (IOException e) {e.printstacktrace ();
            Continue  /** * * @param session * @param error/@OnError public
        void OnError (Session session, throwable error) {System.out.println ("error occurred");
    Error.printstacktrace (); /** * This method is not the same as the above methods.
     Without annotations, it is based on the method you need to add. * * @param message * @throws IOException */public void SendMessage (String message) throws IOException

    {this.session.getBasicRemote (). SendText (message);
    public static synchronized int Getonlinecount () {return onlinecount;
    public static synchronized void Addonlinecount () {websocketchat.onlinecount++; public static synchronized void Subonlinecount () {Websocketchat.onlinecount--;
                public static void Sendmsg (String msg) {for (websocketchat Item:websocketset) {try {
            Item.sendmessage (msg);
                catch (IOException e) {e.printstacktrace ();
            Continue }
        }
    }
}

Effect Chart:

Note: This case refers to the front page of the IBM Library case and is implemented in the background using Java.