Javascript client reading from java web socket

Question

I have a Java websocket that keeps sending a bunch of coordinates which I want to CONSTANTLY intercept from a js client. Here is a simplified version of the java code:

public static void main(String args[]) throws IOException {
    final int portNumber = 2500;
    System.out.println("Creating server socket on port " + portNumber);
    ServerSocket serverSocket = new ServerSocket(portNumber);

    while (true) {
        Socket socket = serverSocket.accept();
        OutputStream os = socket.getOutputStream();
        PrintWriter pw = new PrintWriter(os, true);

        pw.println("test");
        pw.println("\r");

    }
    //later on close connection
    pw.close();
    socket.close();
}

As for my js code here is how it looks like:

var connection; 
   try{
         connection = new MozWebSocket('ws://localhost:2500/');
   }catch(e){
         connection = new WebSocket('ws://localhost:2500/');
   }
connection.onopen = function () {console.log('opened');};

connection.onclose = function(evt) { console.log("closed"); };
connection.onmessage = function(evt) { console.log("message"); };
connection.onerror = function(evt) { console.log(evt); };

After running this I get something like " Error during WebSocket handshake: No response code found in status line " and I understand that it's a difficult problem to overcome from a javascript client. Thus I'm wondering if I should rearrange the way I implemented the websocket or should I make a websocket server instead? But I am not sure if it will still allow me to constantly read the data my socket will be broadcasting at ALL TIMES. Thank you in advance.

Answer 1

You realize that websockets is a protocol right? It is not just sending plaintext.

I made an open source java webserver called Bowser that supports websockets. You can take a look at some of the code here for inspiration or just use the library: https://github.com/mirraj2/Bowser/tree/master/src/bowser/websocket

To start a websocket server, it is as simple as:

int port = 12345;
 new WebSocketServer(port).onOpen(socket->{
   System.out.println("Client connected: " + socket);
 }).start();