Merge origin/master

projects/Assignments/FinalProjects/2018March/ConardSnell/ConardTcpClient.java

+//package tcpclient;
+
+import java.io.*;
+import java.net.*;
+
+/**
+ * Before, we always used telnet to connect to the server. We
+ * are now writing our own program to do the connection.
+ * 
+ * As you will see, when we run this after we start the server
+ * we will see the same string telnet printed, sent by the server.
+ * The output at the server will show different socket pairs for
+ * each time we ran it.
+ * 
+ * @author mcgredo
+ */
+public class ConardTcpClient {
+
+  
+    public static void main(String[] args) 
+    {
+        try
+        {
+           System.out.println("creating socket");
+           
+           // We request an IP to connect to ("localhost") and
+           // port number at that IP (2317). This establishes
+           // a connection to that IP in the form of the Socket
+           // object; the server uses a ServerSocket to wait for
+           // connections.
+           Socket socket = new Socket("localhost", 2317); 
+           
+           // Read the single line written by the server. We'd
+           // do things a bit differently if many lines to be read
+           // from the server, instead of one only.
+           InputStream is = socket.getInputStream();
+           InputStreamReader isr = new InputStreamReader(is);
+           BufferedReader br = new BufferedReader(isr);
+           
+           String serverMessage = br.readLine();
+           System.out.println("What is your location?    " + serverMessage);
+           
+        }
+        catch(Exception e)
+        {
+            System.out.println(e);
+            System.out.println("Problem with client");
+        }
+
+    }
+    
+}

projects/Assignments/FinalProjects/2018March/ConardSnell/ConardTcpServer.java

+//package tcpserver;
+
+import java.io.*;
+import java.net.*;
+
+/**
+ * Very slightly more complex than example1. A complete copy of
+ * example 2. 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.
+ * 
+ * telnet localhost 2317
+ * 
+ * If you're sophisticated you can contact the instructor's computer
+ * while running this program.
+ * 
+ * telnet <ipOfServersLaptop> 2317
+ * 
+ * And have him display the socket pairs he got.
+ * @author mcgredo
+ */
+public class ConardTcpServer 
+{
+
+    public static void main(String[] args) 
+    {
+        try
+        {
+            // ServerSocket waits for a connection from a client. 
+            // Notice that it is outside the loop; ServerSocket
+            // needs to be made only once.
+            
+            ServerSocket serverSocket = new ServerSocket(2317);
+//            System.out.println("socketCreated"); 
+
+            // Loop, infinitely, waiting for client connections.
+            // Stop the program somewhere else.
+            while(true)
+            {
+                Socket clientConnection = serverSocket.accept();
+                OutputStream os = clientConnection.getOutputStream();
+                PrintStream ps = new PrintStream(os);
+
+                ps.println("My location is 1,2,5");
+                
+                // 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();
+                
+                // 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 ))
+                // Socket pair: (( /0:0:0:0:0:0:0:1, 2317 ), ( /0:0:0:0:0:0:0:1, 54881 ))
+                //
+                // Why is the first IP/port the same, while the second set has
+                // different ports?
+
+
+                System.out.println("Socket pair: (( " + localAddress.toString() + ", " + localPort + " ), ( " + 
+                        remoteAddress.toString() + ", " + remotePort + " ))");
+                
+                // 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();
+                clientConnection.close();
+            }
+       }
+        catch(Exception e)
+        {
+            System.out.println("problem with networking");
+        }
+       
+    }
+    
+}
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