multi clients connect to udp server

[bachma7]

hi every body,i have a question- i programing UDP server to download file,it 's work but it can serve only one client one time, how could i create a udp server that can serve a lot clients at the same time. thank you very much.

[fishtoprecords]

Why are you using UDP?
Moving a file is exactly why TCP was invented.

If you use UDP, you have to implement all the error correction and out of order stuff yourself.

[neilcoffey]

Essentially, you have to "manage it". That's the thing about UDP.

I think you have a couple of options. The first is, just have a single DatagramSocket object. This could be a simple option if the result of every received datagram is to immediately send out a corresponding packet. Obviously, you check the packet to see which client send the request, and send back a packet to that client.

Java also supports the pretend notion of "connecting" datagram sockets to a client (i.e. limiting a DatagramSocket object to sending/receiving from a particular client). So you could have a DatagramSocket object per client that you send to, and use a traditional server model of having worker threads that send the data back. This would be a better option if the server needs to "think" a little after receiving each request before sending back the response.

[bachma7]

Essentially, you have to "manage it". That's the thing about UDP.

I think you have a couple of options. The first is, just have a single DatagramSocket object. This could be a simple option if the result of every received datagram is to immediately send out a corresponding packet. Obviously, you check the packet to see which client send the request, and send back a packet to that client.

Java also supports the pretend notion of "connecting" datagram sockets to a client (i.e. limiting a DatagramSocket object to sending/receiving from a particular client). So you could have a DatagramSocket object per client that you send to, and use a traditional server model of having worker threads that send the data back. This would be a better option if the server needs to "think" a little after receiving each request before sending back the response.

thanks for your relpy. i create a loop which receive a connection from once client, then i create a thread to transfer file to that client while the loop go back to listen other connection.
but the problem is when i create a thread, program said that "address is used", but which my knowledge,a UDPserver can communicate with many clients at the same socket. please help me!!

[neilcoffey]

I wonder if you could post appropriate snippets of your code, with the exact line where you're getting "address is used" (plus the actual, verbatim error).

[kirbushok]

Please suggest some firewall.