Socket Programming

Chapter 3 Socket Programming Lecturer: Sivadon Chaisiri Mathematics, Statistics and Computer Department Faculty of Science, Ubon Rajathanee University

Protocols Application = HTTP, FTP, SMTP, NSF, Telnet, SSH, ECHO, … Presentation = SMB, NCP, … Session = SSH, NetBIOS, RPC, … Transport = TCP, UDP, … Network = IP, ICMP, IPX Data link = Ethernet, Token Ring, ISDN, … Physical = 100BASE-T, 1000BASE-T, 802.11

IP, TCP, and UDP IP (Internet Protocol) TCP (Transmission Control Protocol) UDP (User Datagram Protocol) = Unreliable communication, no ordering guarantee (e.g., DNS, TFTP, VoIP, …)

Ports A port is a special number present in the data packet. Ports are typically used to map data to a particular process running on a computer (i.e., which process associates with the data determining by port number) IANA is responsible for assigning TCP and UDP port numbers to specific used. Well-known ports (0-1023) Registered ports (1024-49151) Dynamic and/or Private ports (49152-65535)

Socket Application A socket is a connection between two hosts (endpoints). A socket can perform 7 basic operations. Connect to a remote machine Send data Receive data Close a connection Bind to a port Listen for incoming data Accept connections from remote machines on the bound port

Endpoint-to-Endpoint Communications

Java and Socket java.net.Socket Constructors: Socket(InetAddress address, int port) Socket(String host, int port) Socket(InetAddress address, int port, InetAddress localAddr, int localPort) Methods: InputStream getInputStream() Out putStream getOutputStream() void close() InetAddress getLocalAddress() int getLocalPort() void setSoTimeout(int timeout)

Java and Socket java.net.ServerSocket Constructors: ServerSocket(int port) Methods: Socket accept() void close() void setSoTimeout(int timeout)

Streams More stream classes InputStream : DataInputStream, ObjectInputStream OutputStream : DataOutputStream, ObjectOutputStream

Code: Socket Information import java . net . Socket; public class SocketInfo { public static void main ( String [] args ) throws Exception { Socket socket = new Socket (" www . sanook . com " , 80 ) ; System . out . println (" Connected to " + socket . getInetAddress () + " on port " + socket . getPort () + " from port " + socket . getLocalPort () + " of " + socket . getLocalAddress ()) ; } }

Steps to develop a socket app Client-Side Bind Socket object with a specified host&port then connect to the host&port [option] Send data via stream (from getOutputStream) Wait for a response of the host via getInputStream Server-Side Bind ServerSocket object with a specified port Listening for the incoming requesting Accept connection while listened to an incoming contact and get its Socket reference Send/Receive data via streams of the Socket Object

Code: Time Server import java . io . DataOutputStream; import java . net . *; import java . util . Date; public class TimeServer { public static void main ( String [] args ) throws Exception { ServerSocket server = new ServerSocket ( 7000 ) ; System . out . println (" Server is started ") ; while ( true ) { Socket socket = server . accept () ; DataOutputStream dos = new DataOutputStream ( socket . getOutputStream ()) ; String time = new Date (). toString () ; dos . writeUTF ( time ) ; socket . close () ; } } }

Code: Time Client import java . io . DataInputStream; import java . io . DataOutputStream; import java . net . Socket; public class TimeClient { public static void main ( String [] args ) throws Exception { Socket socket = new Socket (" localhost " , 7000 ) ; DataInputStream din = new DataInputStream ( socket . getInputStream ()) ; String time = din . readUTF () ; System . out . println ( time ) ; } }

Code: Hello Server import java . io . *; import java . net . *; public class HelloServer { public static void main ( String [] args ) throws Exception { ServerSocket server = new ServerSocket ( 12345 ) ; System . out . println (" Server is started ") ; while ( true ) { Socket socket = server . accept () ; DataInputStream dis = new DataInputStream ( socket . getInputStream ()) ; DataOutputStream dos = new DataOutputStream ( socket . getOutputStream ()) ; String name = dis . readUTF () ; System . out . println (" I see " + name ) ; dos . writeUTF (" Hello " + name ) ; socket . close () ; } } }

Code: Hello Client import java . io*; import java . net . *; public class HelloClient { public static void main ( String [] args ) throws Exception { Socket socket = new Socket (" localhost " , 12345 ) ; DataInputStream din = new DataInputStream ( socket . getInputStream ()) ; DataOutputStream dos = new DataOutputStream ( socket . getOutputStream ()) ; String name = " World " ; if ( args . length > 0 ) name = args [ 0 ] ; dos . writeUTF ( name ) ; String message = din . readUTF () ; System . out . println ( message ) ; } }

Code: Busy Hello Server import java . io . *; import java . net . *; public class BusyHelloServer { public static void main ( String [] args ) throws Exception { ServerSocket server = new ServerSocket ( 12345 ) ; while ( true ) { Socket socket = server . accept () ; DataInputStream dis = new DataInputStream ( socket . getInputStream ()) ; DataOutputStream dos = new DataOutputStream ( socket . getOutputStream ()) ; String name = dis . readUTF () ; System . out . println (" I see " + name ) ; for ( int i = 0 ; i < 10 ; i ++) { Thread . sleep ( 1000 ) ; System . out . println (" Delay for " + name + " # " + i ) ; } dos . writeUTF (" Hello " + name ) ; socket . close () ; } } }

Code: Multithread Hello Server import java . io . *; import java . net . *; public class ThreadingHelloServer extends Thread { Socket soc; public ThreadingHelloServer ( Socket soc ) { this . soc = soc; } public void run () { try { DataInputStream dis = new DataInputStream ( soc . getInputStream ()) ; DataOutputStream dos = new DataOutputStream ( soc . getOutputStream ()) ; String name = dis . readUTF () ; System . out . println (" I see " + name ) ; for ( int i = 0 ; i < 10 ; i ++) { Thread . sleep ( 1000 ) ; System . out . println (" Delay for " + name + " # " + i ) ; } dos . writeUTF (" Hello " + name ) ; soc . close () ; } catch ( Exception ex ) {ex . printStackTrace () ;} } public static void main ( String [] args ) throws Exception { ServerSocket server = new ServerSocket ( 12345 ) ; while ( true ) { Socket socket = server . accept () ; new ThreadingHelloServer ( socket ) .start () ; } } }

Code: Multithread Hello Server (Short Form) import java.io.*; import java.net.*; public class ThreadingHelloServer2 { public static void main(String[] args) throws Exception { ServerSocket server = new ServerSocket(12345); System.out.println("Server is started"); while(true) { final Socket socket = server.accept(); Thread t = new Thread() { public void run() { try { DataInputStream dis = new DataInputStream(socket.getInputStream()); DataOutputStream dos = new DataOutputStream(socket.getOutputStream()); String name = dis.readUTF(); System.out.println("I see " + name); for (int i = 0 ; i < 10 ; i++) { Thread.sleep(1000); System.out.println("Delay for " + name + " #" + i); } dos.writeUTF("Hello " + name); socket.close(); } catch(Exception ex) { ex.printStackTrace(); } }}; t.start(); }}}

Socket Programming

More Related Content

What's hot (20)

Viewers also liked (19)

Similar to Socket Programming (20)

Recently uploaded (20)

Socket Programming