Tcp/ip server sockets

tcp/ip client sockets

1. Tcp /ip server sockets, tcp /ip client sockets R.Pavithra Department of CS&IT Nadar saraswathi college of arts & science, theni .

2. contents Introduction Sockets Server Socket And Client Socket Tcp / Ip In Java Types Of Sockets In Java Tcp /Ip Server Socket Tcp /Ip Client Socket Conculsion

3. Introduction sockets The term socket programming refers to writing programs that execute across multiple computers in which the devices are all connected to each other using a network. There are two communication protocols that one can use for socket programming :User datagram protocol(UDP)and Transfer control protocol(TCP)

4. Server socket and client socket A server socket keeps on listening to any incoming connections from any of the clients. When you create a client socket, you simply specify the server address and port. You never bind or listen using a client socket. You simply connect a client socket . On the other hand you dont connect using a server socket.

5. TCP/IP in java Accessing TCP/IP from java is Straightforward. The main functionality is in the following classes: Java.net.InetAddress: Represents an IP address( either IPV4or IPV6) and has methods for performing DNS lookup( next slide). Java.net.Socket: Represents a TCP socket. Java.net.ServerSocket: Represents a server socket which is capable of waiting for requests from clients.

6. Types of sockets in java Java provides three different types of sockets connection-oriented(TCP) sockets are implemented with the socket class. Connectionless(UDP) sockets uses the Datagram Socket class. A third type is the Multicast Socket class, which is a subclass of the datagram Socket class. Server client

7. TCP/IP SERVER SOCKETS A socket in java is one endpoint of two-way communication link between two programs runnning on the network. A socket is bound to a port number so that the TCP layer can identify the application that data is destined to be sent to . An endpoint is a combination of an IP address and a port number.

8. continue syntax descriptions Server Socket( int port ) throws IOException Creates server socket on the specified port with a queue length of 50 Server Socket( int port, int maxQueue) Throws IOException Creates a server socket on the specified port with a maximum queue length of maxQueue. Server Socket( it port, int maxQueue,inetAddress local Address) Throws IOException Creates a server socket on the specified port with a maximum queue length of maxQueue, on a multihomed host, local Address specifies the ip address to which this socket binds.

9. Example program for server socket Import java.net.*; Import java.io.*; Public class serverside { Private Socket socket =null; Private serversocket =null; Sop(“server started”); Sop(“waiting for client”); Socket= server.accept (); Sop(“client accepted”); In=new dataintputstream ( New bufferedinputstream ( socket.getInputstream ())); String line=””; While(! line.equals (‘over ”)){

10. Try{ Line= input.readline (); Out.writeUTF (line);} Catch(IOException i ){ Sop( i );}} Sop(“closing connection”); Socket.close (); In.close ();} Catch(IOException i ){ Sop( i );}} Public static void main( stringargs []){ Server server =new server(5000);}}  

11. TCP/IP CLIENT SOCKET TCP/IP client sockets. TCP/IP sockets are used to implement reliable, bidirectional, persistent, point-to-point, stream-based connections between hosts on the internet. A socket can be used to connect java’s I/O system to other programs that may reside either on the local machine or on any other machine on the internet.

12. syntax description InetAddress getInetAddress() Returns the InetAdd associated with the socket object .It returns null If the socket is not connected. Intgetport() Returns the remote port to which the invoking socket object is connected . It returns O if the socket is not connected. Intgetlocalport() Returns the local port to which the invoking socket object is bound. It returns -1if the socket is not bound.

13. Continue…… You can gain access I/P and O/P streams associated with socket by use of Get I/P stream() Get O/P stream() Each can throw an IOException if the socket has been invalidated by a loss of connections. syntax description inputstream getI/ Pstream () Throws IOException Returns the inputs stream associated with the invoking socket Outputstream get O/P stream() throws IOException Returns the outputs stream associated with the invoking socket

14. Other method Syntax Description “including connect()” Which allows you to specify a new connections “is connected()” Which returns true if the socket is connected to server. “is bound()” Which returns if the socket is bound to an address “is closed()” Which returns true if the socket is closed.

15. Example program client socket Import java.net.*; Import java.io.*; Public class clientprogram { Private Socket socket =null; Private datainputstream input=null; Private dataoutputstream output=null; Public client(string address,int port){ Try{ Socket =new socket( address,port ); Sop(“connected”); Input=new datainputstream ( system.in ); Out=new dataoutputstream ( socket.getoutputstream ());} Catch( unknownHostException u){

16. Sop(u);} Catch(IOException i ){ Sop( i );} String line=””; While(! line.equals (‘over”)){ Try{ Line= input.readline (); Out.writeUTF (line);} Catch(IOException i ){ Sop( i );}} Try { input.close (); Out.close (); Socket.close ();} Catch(IOException i ){ Sop( i );}} Public static void n= amin ( stringargs []){ Client client =new client(127.0.0.1”,5000);}}

17. conculsion Programing client and server applications in java is fun and challenging. Programming socket programming injava is much easier than doing it in other languages such as C. Key words: Client,servers,TCP / IP,port,number,sockets , java sockets.