Sending data through sockets in java

Question

I am currently working on a one server many clients system. I am trying to get it so the server can send out one command, through a PrintWriter, that will go through to all of the clients connected on that socket. However in practice the command only goes through to one client. All of the clients are created on one socket, and all use the same Scanner. Is what I am trying to do possible?

Some code(incase it helps)

Creation of the socket:

serverSocketRefresh = new ServerSocket(PORTREFRESH); refresh = serverSocketRefresh.accept(); Creation of the Print Writer and the Scanner: networkOutputRefresh = new PrintWriter(refresh.getOutputStream(), true); networkInput = new Scanner(refresh.getInputStream());

Ceation of the clients:

do { // Wait for client... client = serverSocket.accept(); System.out.println("\nNew client accepted.\n"); handler = new ClientHandler(client,networkOutputRefresh, itemArray, bidderArray); handler.start(); } while (true);

The command im trying to transmit to all of the clients:

public static void updatePrice() { networkOutputRefresh.println("1"); }

what kind of different clients are connected on one socket?

M Sach
– M Sach

2013-05-01 03:56:17 +00:00
Commented May 1, 2013 at 3:56 — M Sach
– M Sach, Commented May 1, 2013 at 3:56

Juned Ahsan · Accepted Answer · 2013-05-01 04:34:58Z

I am not sure if I correctly understand your code but it seems you are using a single reference of client. And your client reference will be holding the last client reference and hence the printwrite is writing only for that client. Ideally if you want to publish something to all the clients then you should have a collection of client references.Whenever you get an accept on the server socket, add the new client reference to your collection. And whenever you have to publish to all the clients just iterate over your client collection and publish using their associated printwriters.

AppleDash · Accepted Answer · 2013-05-01 03:47:17Z

0

Why not just use a BufferedReader and BufferedWriter, and make a new one each time you accept a client?

Edit: Or, if that '1' is the only thing you will ever send over that socket, just send it over the socket directly, as a byte. I believe the method is something like socket.write(new byte[] { 1 }, 0, 1), and to read on the other end, socket.read(buffer, 0, 1), where buffer is a byte array of length 1.

answered May 1, 2013 at 3:47

AppleDash

1,7742 gold badges16 silver badges27 bronze badges

9 Comments

user2254372 Over a year ago

It is a uni project all about sockets, and the tutorial specifically tells us to use PrintWriters and scanners:/

AppleDash Over a year ago

@user2254372 Ah, OK. PrintWriters and Scanners should work, as long as you make a new one for each client the connects.

user2254372 Over a year ago

Is their no way to do it with a print writer that writes to several threads using the same scanner?

user2254372 Over a year ago

Basically, I have a thread on each client that sits and waits for the command, and I want the server to send one command out to all the different threads telling them all to update simultaneously, but I have no idea if it is possible:/

user2254372 Over a year ago

If I create a PrintWriter and Scanner for each new client, only one client will receive the message though?

|

Collectives™ on Stack Overflow

Sending data through sockets in java

2 Answers 2

Comments

9 Comments

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

9 Comments

Related