Java Example Event Programming

Network Program

import java.net.*;

class dataclient

{

public static DatagramSocket ds;

public static byte buffer[] = new byte[1024];

public static void main(String args[]) throws Exception

{

ds = new DatagramSocket(1999);

while(true)

{

DatagramPacket p = new DatagramPacket(buffer,buffer.length);

ds.receive(p);

System.out.println(new String(p.getData(),0,p.getLength()));

}

}

}



import java.net.*;

class dataserver

{

public static DatagramSocket ds;

public static byte buffer[] = new byte[1024];

public static void main(String args[]) throws Exception

{

InetAddress ia = InetAddress.getByName(args[0]);

ds = new DatagramSocket(1666);

int pos=0;

while(true)

{

int c = System.in.read();

switch(c)

{

case 'q':

System.out.println("Server quits");

return;

case '\r':

break;

case '\n':

ds.send(new DatagramPacket(buffer,pos,ia,1999));

pos=0;

break;

default:

buffer[pos++] = (byte) c;

}

}

}

}



// a simple client that sends lines to server and reads lines from server

import java.net.*;

import java.io.* ;

public class tcpclient

{

public static void main(String arg[]) throws IOException

{

InetAddress addr;

if(arg.length > 0)

addr = InetAddress.getByName(arg[0]);

else

addr = InetAddress.getByName("localhost");

System.out.println("addr = " + addr);

Socket s = new Socket(addr,1666);

try

{

System.out.println("Socket = " + s);

BufferedReader in = new BufferedReader(new InputStreamReader(s.getInputStream()));

PrintWriter out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(s.getOutputStream())),true);

for(int i =0;i<5;i++)

{

out.println("howdy " + i);

String str = in.readLine();

System.out.println(str);

}

out.println("End");

} finally

{

System.out.println("closing...");

s.close();

}

}

}



import java.io.* ;

import java.net.* ;

public class tcpserver

{

public static void main(String arg[]) throws IOException

{

ServerSocket ss = new ServerSocket(1666);

System.out.println("Server started " + ss);

try

{

Socket s = ss.accept();

try

{

System.out.println("Connection accepted " + s);

BufferedReader br = new BufferedReader(new InputStreamReader(s.getInputStream()));

// output is flushed by printwriter

PrintWriter pw = new PrintWriter(new OutputStreamWriter(s.getOutputStream()),true);

while(true)

{

String str = br.readLine();

if(str.equals("End"))

break;

System.out.println("Echoing : " + str);

pw.println(str);

}

}

finally

{

System.out.println("closing ...");

s.close();

}

}

finally

{

ss.close();

}

}

}



import java.net.*;

class client

{

public static DatagramSocket ds;

public static byte buffer[] = new byte[1024];

public static void main(String arg[]) throws Exception

{

ds = new DatagramSocket(6);

while(true)

{

String a;

DatagramPacket p = new DatagramPacket(buffer,buffer.length);

ds.receive(p);

a=new String(p.getData(),p.getLength(),1);

if (a.equals("q"))

{

System.out.println("Server response is shut off now");

return;

}

System.out.println(new String(p.getData(),0,p.getLength()));

}

}

}



import java.net.*;

class dataclient

{

public static DatagramSocket ds;

public static byte buffer[] = new byte[1024];

public static void main(String args[]) throws Exception

{

ds = new DatagramSocket(1999);

while(true)

{

DatagramPacket p = new DatagramPacket(buffer,buffer.length);

ds.receive(p);

System.out.println(new String(p.getData(),0,p.getLength()));

}

}

}



import java.net.*;

class dataserver

{

public static int serverport = 1666;

public static int clientport = 1999;

public static DatagramSocket ds;

public static byte buffer[] = new byte[1024];

public static void server() throws Exception

{

int pos=0;

while(true)

{

int c = System.in.read();

switch(c)

{

case -1:

System.out.println("Server quits");

return;

case '\r':

break;

case '\n':

ds.send(new DatagramPacket(buffer,pos,InetAddress.getLocalHost(),clientport));

pos=0;

break;

default:

buffer[pos++] = (byte) c;

}

}

}

public static void client() throws Exception

{

while(true)

{

DatagramPacket p = new DatagramPacket(buffer,buffer.length);

ds.receive(p);

System.out.println(new String(p.getData(),0,p.getLength()));

}

}

public static void main(String args[]) throws Exception

{

if(args.length ==1)

{

ds = new DatagramSocket(serverport);

server();

}

else

{

ds = new DatagramSocket(clientport);

client();

}

}

}



import java.net.*;

class inet

{

public static void main(String arg[]) throws UnknownHostException,MalformedURLException

{

InetAddress b = InetAddress.getLocalHost();

System.out.println(b);

String s = b.getHostAddress();

System.out.println(s);

InetAddress c = InetAddress.getByName(arg[0]);

System.out.println(c);



URL u = new URL("file:/j:/j002");

}

}

import java.net.*;

class server

{

public static DatagramSocket ds;

public static byte buffer[] = new byte[1024];

public static void main(String a[]) throws Exception

{

InetAddress ia = InetAddress.getByName("tmproj13");

System.out.print("Connect to ");

System.out.println(ia);

ds = new DatagramSocket(123);

int pos=0;

while(true)

{

int c = System.in.read();

switch(c)

{

case 'q':

System.out.println("Server quits");

return;

case '\r':

break;

case '\n':

DatagramPacket dp = new DatagramPacket(buffer,pos,ia,456);

ds.send(dp);

pos=0;

break;

default:

buffer[pos++] = (byte) c;

}

}

}

}



// a simple client that sends lines to server and reads lines from server

import java.net.*;

import java.io.* ;

public class tcpclient

{

public static void main(String arg[]) throws IOException

{

InetAddress addr = InetAddress.getByName(null);

// instead of null you can use localhost

System.out.println("addr = " + addr);

Socket s = new Socket(addr,tcpserver.port);

try

{

System.out.println("Socket = " + s);

BufferedReader in = new BufferedReader(new InputStreamReader(s.getInputStream()));

PrintWriter out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(s.getOutputStream())),true);

for(int i =0;i<10;i++)

{

out.println("howdy " + i);

String str = in.readLine();

System.out.println(str);

}

out.println("End");

} finally{

System.out.println("closing...");

s.close();

}

}

}



import java.io.* ;

import java.net.* ;

public class tcpserver

{

public static final int port=8080;

public static void main(String arg[]) throws IOException

{

ServerSocket ss = new ServerSocket(port);

Socket s ;

System.out.println("Server started " + ss);

try {

s = ss.accept();

System.out.println("Connection accepted " + s);

BufferedReader br = new BufferedReader(new InputStreamReader(s.getInputStream()));

// output is flushed by printwriter

PrintWriter pw = new PrintWriter(new OutputStreamWriter(s.getOutputStream()),true);

while(true)

{

String str = br.readLine();

if(str.equals("stop"))

break;

System.out.println("Echoing : " + str);

pw.println(str);

}

}finally {

System.out.println("closing ...");

s.close();

ss.close();

}}}



import java.net.*;

class udpclient

{

public static int serverport = 666;

public static int clientport = 999;

public static DatagramSocket ds;

public static byte buffer[] = new byte[1024];

public static void client() throws Exception

{

while(true)

{

DatagramPacket p = new DatagramPacket(buffer,buffer.length);

ds.receive(p);

System.out.print(new String(p.getData(),0,p.getLength()));

}

}

public static void main(String args[]) throws Exception

{

ds = new DatagramSocket(clientport);

client();

}

}

import java.net.*;

class udpserver

{

public static int serverport = 666;

public static int clientport = 999;

public static DatagramSocket ds;

public static byte buffer[] = new byte[1024];

public static void server() throws Exception

{

int pos=0;

while(true)

{

InetAddress ia = InetAddress.getByName("rad-tm-17");

int c = System.in.read();

ds.send(new DatagramPacket(buffer,pos,ia,clientport));

pos=0;

buffer[pos++] = (byte) c;

}

}

public static void main(String args[]) throws Exception

{

ds = new DatagramSocket(serverport);

server();

}}