Tcp Echo Client HelppppNa faksu moramo da napisemo TCP Echo Client koji ce da posalje neku poruku perma TCP Echo Serveru i tad ce taj Server da "odjekne" (ili ti echo na engleskom) poruku nazad.
Znaci server drzi nastavnik a ja kao student moram da napisem Client program kojeg kad pokrenem koristeci "command line" u formatu:
javac Client.java (da se compile)
java Client IPadresa PORTbroj "poruka" (da posalje poruku)
znaci
args[0]=server
args[1]=broj porta
args[2]=poruka
Ne mora da bude bas u tom redosledu al je "pozeljno".
E sad ja posto jako malo znam Java Programming ja sam lepo otisao na GOOGLE i ukucao TCPEchoClient.java i nasao neke programcice i izabrao jedan koji najvise razumijem ali i dalje ne razumem sve.
Pa bi zamolio citaoce da mi objasne sta TACNO svaka linija programa radi.
Code:
import java.net.*; // for Socket
import java.io.*; // for IOException and Input/OutputStream
public class Client {
public static void main(String[] args) throws IOException
{
if ((args.length < 2) || (args.length > 3)) // Test for correct # of args
throw new IllegalArgumentException("Parameter(s): <Server> <Word> [<Port>]");
String server = args[0]; // Server name or IP address
// Convert input String to bytes using the default character encoding
byte[] byteBuffer = args[1].getBytes();
int servPort = (args.length == 3) ? Integer.parseInt(args[2]) : 7;
// Create socket that is connected to server on specified port
Socket socket = new Socket(server, servPort);
System.out.println("Connected to server...sending echo string");
InputStream in = socket.getInputStream();
OutputStream out = socket.getOutputStream();
out.write(byteBuffer); // Send the encoded string to the server
// Receive the same string back from the server
int totalBytesRcvd = 0; // Total bytes received so far
int bytesRcvd; // Bytes received in last read
while (totalBytesRcvd < byteBuffer.length)
{
if ((bytesRcvd = in.read(byteBuffer, totalBytesRcvd,
byteBuffer.length - totalBytesRcvd)) == -1)
throw new SocketException("Connection close prematurely");
totalBytesRcvd += bytesRcvd;
}
System.out.println("Received: " + new String(byteBuffer));
socket.close(); // Close the socket and its streams
}
}
import java.net.*; // for Socket
import java.io.*; // for IOException and Input/OutputStream
public class Client {
public static void main(String[] args) throws IOException
{
if ((args.length < 2) || (args.length > 3)) // Test for correct # of args
throw new IllegalArgumentException("Parameter(s): <Server> <Word> [<Port>]");
String server = args[0]; // Server name or IP address
// Convert input String to bytes using the default character encoding
byte[] byteBuffer = args[1].getBytes();
int servPort = (args.length == 3) ? Integer.parseInt(args[2]) : 7;
// Create socket that is connected to server on specified port
Socket socket = new Socket(server, servPort);
System.out.println("Connected to server...sending echo string");
InputStream in = socket.getInputStream();
OutputStream out = socket.getOutputStream();
out.write(byteBuffer); // Send the encoded string to the server
// Receive the same string back from the server
int totalBytesRcvd = 0; // Total bytes received so far
int bytesRcvd; // Bytes received in last read
while (totalBytesRcvd < byteBuffer.length)
{
if ((bytesRcvd = in.read(byteBuffer, totalBytesRcvd,
byteBuffer.length - totalBytesRcvd)) == -1)
throw new SocketException("Connection close prematurely");
totalBytesRcvd += bytesRcvd;
}
System.out.println("Received: " + new String(byteBuffer));
socket.close(); // Close the socket and its streams
}
}
Razumijem da treba da se spojim na server putem socketa zvan "sock", razumijem da mora neki buffer da ima koji ce da spremi ukucana slova sa tastature, i razumijem da onda to mora da posalje i razumijem da mora da tu poruku primi od servera i pokaze na ekran (isto putem nekog buffera).
Kao sto vidite vec ima //comments ali ako bi neko mogao jos detaljnije da mi objasni sve to, POGOTOVO
int servPort = (args.length == 3) ? Integer.parseInt(args[2]) : 7;
i
if ((bytesRcvd = in.read(byteBuffer, totalBytesRcvd,
byteBuffer.length - totalBytesRcvd)) == -1)
throw new SocketException("Connection close prematurely");
totalBytesRcvd += bytesRcvd;
Pliz narode pomagaj. HVALA UNAPRED !!!
