Local connection

[Totte_ch]

Hey

I read a book, years ago, about Java. One of the last chapters was about how to create connections and send/reveice messages between a computer and a server.

Now I need to create a connection between two computers in the same network (peer to peer, or what is it called). The examples in the book used java.net.MulticastSocket to create a connection to a server. When I try the same with my second computer (connected in same network), I get a UnknownHost-exception.

Does anybody know how to create a connection between two computers in same network?
I would like to know how to send and receive messages/bytes too.


Thanks in advance
Totte

[chazzy]

do you mean something like a P2P/IM client type of thing?

[Totte_ch]

P2P = Peer 2 Peer? IM = Instant Messaging? - Right?

Well, I mean a connection between two computers, a connection without a server, so the applications could "talk" by the network. I'm making a game that could be played in multiplayer between computers in same network (without any server). I just want to send messages (bytes of code) between computers.

Example: Computer 1 handles a key press (arrow down) and sends the command to Computer 2. Every single computer computes the command/key press, and draws the new game area with the character owned by Computer 1 (player 1) one square down.

Peer to peer - Yes, maybe you could call this connection that. I mean, there is no server involved.
Instant Messaging - Well, there is a chat function in my game (or will be) and I must be able to send messages, but it's not only a chat program...

I think every computer must be like a server (listen to ports, accept connections etc.), but I don't know how to do it.

I am maybe not good at explaining. Thanks for helping me!

[chazzy]

no you're right. every computer in the network is both a client and a server. you just need to have 2 threads on every machine, one to send data and another to receive data.

[Totte_ch]

But how do I create a connection? I've tried with java.net.MulticastSocket:
Computer 1 = 192.168.0.101
Computer 2 = 192.168.0.102
The result I got was "java.net.SocketException: Not a multicast address". I need something to connect peer to peer inside a network, not between a public server (like google.com).

[chazzy]

do you have socket servers running on each of those IPs? i believe you need to have a socket server on each group member in the multicast socket group.

it's a bit old, but should give you a decent start

http://java.sun.com/docs/books/tutor...adcasting.html

Also, I've got a book, it's written for java 5, when i was doing some network programming. http://oreilly.com/catalog/9781565928701/