Skip to content
Snippets Groups Projects
Commit 5ba0ace0 authored by Brutzman, Don's avatar Brutzman, Don
Browse files

Merge origin/master

parents fafa174c d1508748
No related branches found
No related tags found
No related merge requests found
package MV3500Cohort2021JulySeptember.homework1.Pugh;
import java.io.*;
import java.net.*;
/**
* Very slightly more complex than example1. The only thing this does
* differently is introduce a loop into the response, so you don't have to
* restart the program after one response. Also, it prints out the socket pair
* the server sees. Run the program via telnet several times and compare the
* socket pairs.
*
* <code>telnet localhost 2317</code>
*
* If you're sophisticated you can contact the instructor's computer while
* running this program.
*
* <code>telnet ipOfServersLaptop 2317</code>
*
* And have that machine display the socket pairs received.
*
* @author pugh
* @author brutzman
*/
public class PughTcp2ConnectionCounting {
/**
* Program invocation, execution starts here
*
* @param args command-line arguments
*/
public static void main(String[] args) {
try {
System.out.println("TcpExample2ConnectionCounting has started and is waiting for a connection.");
System.out.println("Get Ready To Network!!!");
System.out.println(" help: https://savage.nps.edu/Savage/developers.html#telnet");
System.out.println(" enter (nc localhost 2317) or (telnet localhost 2317)...");
// ServerSocket waits for a connection from a client.
// Notice that it is outside the loop; ServerSocket needs to be made only once.
int connectionCount = 0; // state variable
ServerSocket serverSocket = new ServerSocket(2317); // server decides here what port to listen on.
// of interest: often client doesn't care what port it uses locally when connecting to that server port.
// Loop, infinitely, waiting for client connections.
// Stop the program somewhere else.
while (true) {
// blocks! then proceeds once a connection is "accept"ed
try ( Socket clientConnection = serverSocket.accept()) {
connectionCount++; // got another one!
OutputStream os = clientConnection.getOutputStream();
PrintStream ps = new PrintStream(os);
ps.println("This client response was written by server " + PughTcp2ConnectionCounting.class.getName()); // to remote client
System.out.println("This server response was written by server " + PughTcp2ConnectionCounting.class.getName() + "\n"); // to server console
if (connectionCount % 2 == 1) {
System.out.println("Go\n");
}
if (connectionCount % 2 == 0) {
System.out.println("Gators!\n");
}
if (connectionCount % 3 == 1 && connectionCount != 0) {
System.out.println("O'Doyle Rules!!! \n");
}
ps.println("You were connection #" + connectionCount + ", by my count");
// Print some information locally about the Socket connection.
// This includes the port and IP numbers on both sides (the socket pair.)
InetAddress localAddress = clientConnection.getLocalAddress();
InetAddress remoteAddress = clientConnection.getInetAddress();
int localPort = clientConnection.getLocalPort();
int remotePort = clientConnection.getPort(); // remember the prior question, why are 2 ports different?
// My socket pair connection looks like this, to localhost:
// Socket pair: (( /0:0:0:0:0:0:0:1, 2317 ), ( /0:0:0:0:0:0:0:1, 54876 )) note IPv6
// Socket pair: (( /0:0:0:0:0:0:0:1, 2317 ), ( /0:0:0:0:0:0:0:1, 54881 ))
//
// Why is first IP/port the same, while the second set has different ports?
System.out.println("Socket pair: (( " + localAddress.toString() + ", " + localPort + " ), ( "
+ remoteAddress.toString() + ", " + remotePort + " ))");
System.out.println("got another connection, #" + connectionCount); // report progress
// Notice the use of flush() and close(). Without
// the close() to Socket object may stay open for
// a while after the client has stopped needing this
// connection. Close() explicitly ends the connection.
ps.flush();
}
}
} catch (IOException e) {
System.err.println("Problem with " + PughTcp2ConnectionCounting.class.getName() + " networking:"); // describe what is happening
System.err.println("Error: " + e);
// Provide more helpful information to user if exception occurs due to running twice at one time
if (e instanceof java.net.BindException) {
System.err.println("*** Be sure to stop any other running instances of programs using this port!");
}
}
}
}
package MV3500Cohort2021JulySeptember.homework1.Pugh;
package MV3500Cohort2021JulySeptember.homework1;
import java.io.*;
import java.net.*;
......
0% Loading or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment