Client server communication java

Question

I have a problem in a client-server application. The client sends a picture to the server and the server responds with a reply message.

Here is my server code:

public class Server
{
    public static void main(String[] args) throws Exception
    {
        String response="response";
        ServerSocket socket = new ServerSocket(3333);
        while (true)
        {
            Socket clientSocket = socket.accept();

            DataInputStream dis = new DataInputStream(clientSocket.getInputStream());
            FileOutputStream fout = new FileOutputStream("output.jpg");
            int i;
            while ( (i = dis.read()) > -1) 
                fout.write(i);    

            DataOutputStream outToClient= new    DataOutputStream(clientSocket.getOutputStream());

            outToClient.writeBytes(response);

            fout.flush();
            fout.close();
            dis.close();
            outToClient.close();
            clientSocket.close();
        }
    }
}

Client:

public static void main(String[] args) throws Exception
{
    // TODO Auto-generated method stub
    String sentence;
    int i;
    FileInputStream fis = new FileInputStream ("pathphoto.jpg");   
    Socket sock = new Socket ("hostname",3333);
    DataOutputStream os = new DataOutputStream(sock.getOutputStream());
    System.out.println("Sending....");
    while ((i = fis.read()) > -1)
        os.write(i);

    BufferedReader inFromServer= new BufferedReader(new InputStreamReader(sock.getInputStream()));
    sentence=inFromServer.readLine();
    System.out.println("FROM SERVER: " + sentence);
    fis.close();
    os.close();
    sock.close();
}
}

The problem is that the client doesn't receive the response from the server and I think along these lines:

BufferedReader inFromServer= new BufferedReader(new InputStreamReader(sock.getInputStream()));
sentence=inFromServer.readLine();

Because without them the server sends the response.

Any advice on how to fix it?

how are you running this? in two separate threds? if yes, are both the threds alive all the time? — Ravi Bhatt
– Ravi Bhatt, Commented Nov 5, 2012 at 12:18
does any one of your applications close down before the other can read/write to a socket? check if you are not closing sockets too fast. — Ravi Bhatt
– Ravi Bhatt, Commented Nov 5, 2012 at 12:41
You have an extra } at your client code hope that is just a typo or that it does have something to close. — Prix
– Prix, Commented Jun 30, 2013 at 7:05

Rohit · Accepted Answer · 2012-11-05 12:41:33Z

1

Its not stuck in BufferedReader, it is actually stuck in while ((i = fis.read()) > -1) Since your client never told server length of stream, or closed stream server will try to read next byte from inputstream and will be stuck when client is done sending file and waiting for response from server.

When you remove code to read response back from server, client goes ahead and closes all streams and in that case server reads a -1 and goes ahead.

answered Nov 5, 2012 at 12:41

Rohit

5253 silver badges8 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

sqtd Over a year ago

i try to put os.close before BufferedRedear but it launch an exception becouse it closes the socket

Collectives™ on Stack Overflow

Client server communication java

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related