Using SocketChannel sc =(SocketChannel)key.channel();, we can fetch data from port into buffer.
In order to receive the data continuously from port without the loss of data, how the code should be ?
Here is my code
import java.io.*;
import java.net.*;
import java.nio.*;
import java.nio.channels.*;
import java.util.*;
public class MultiPortEcho
{
private int ports[];
private ByteBuffer echoBuffer = ByteBuffer.allocate(32000);
public MultiPortEcho( int ports[] ) throws IOException
{
this.ports = ports;
go();
}
private void go() throws IOException
{
// Create a new selector
Selector selector = Selector.open();
// Open a listener on each port, and register each one
// with the selector
for (int i=0; i<ports.length; ++i)
{
ServerSocketChannel ssc = ServerSocketChannel.open();
ssc.configureBlocking( false );
ServerSocket ss = ssc.socket();
InetSocketAddress address = new InetSocketAddress( ports[i] );
ss.bind( address );
SelectionKey key = ssc.register( selector, SelectionKey.OP_ACCEPT );
System.out.println( "Going to listen on "+ports[i] );
}
while (true)
{
int num = selector.select();
System.out.println("num::::"+num);
Set selectedKeys = selector.selectedKeys();
Iterator it = selectedKeys.iterator();
while (it.hasNext())
{
SelectionKey key = (SelectionKey)it.next();
if ((key.readyOps() & SelectionKey.OP_ACCEPT)== SelectionKey.OP_ACCEPT)
{
// Accept the new connection
ServerSocketChannel ssc = (ServerSocketChannel)key.channel();
SocketChannel sc = ssc.accept();
sc.configureBlocking( false );
// Add the new connection to the selector
SelectionKey newKey = sc.register(selector,SelectionKey.OP_READ);
it.remove();
System.out.println( "Got connection from "+sc );
}
else if ((key.readyOps() & SelectionKey.OP_READ)== SelectionKey.OP_READ)
{
// Read the data
SocketChannel sc =(SocketChannel)key.channel();
System.out.println("sc::::"+sc);
// data to fetched from channel and dump into the datatbase
int bytesEchoed = 0;
//while(true)
{
echoBuffer.clear();
int r = sc.read(echoBuffer);
System.out.println("r:::" + r);
/*int pos=echoBuffer.position();
System.out.println("pos:::" +pos);*/
if (r == -1)
{
//echoBuffer.flip();
echoBuffer.rewind();
byte[] array = new byte[100000];
while (echoBuffer.hasRemaining())
{
int n = echoBuffer.remaining();
System.out.println("size:" + n);
echoBuffer.get(array,0,n );
System.out.println(new String(array,0,n));
key.cancel();
it.remove();
}
}
/*int pos=echoBuffer.position();
System.out.println("pos:::" + pos);
if(r<=0)
{
echoBuffer.flip();
for (int j = 0; j < pos; j++ )
{
String ss =Integer.toHexString(echoBuffer.get());
if (ss.length() == 1)
System.out.print("0" + ss + " ");
else if (ss.length() > 2)
System.out.print(ss.substring(6) + " ");
else System.out.print(ss + " ");
}
break;
}
echoBuffer.flip();
sc.write( echoBuffer );
bytesEchoed += r;*/
}
//System.out.println( "Echoed "+bytesEchoed+" from "+sc );
//it.remove();
}
}
//System.out.println( "going to clear" );
// selectedKeys.clear();
//System.out.println( "cleared" );
}
}
static public void main( String args[] ) throws Exception
{
FileOutputStream fileoutputstream = new FileOutputStream("MultiPort.txt", false);
PrintStream printstream = new PrintStream(fileoutputstream);
System.setOut(printstream);
if (args.length<=0) {
System.err.println( "Usage: java MultiPortEcho port [port port ...]" );
System.exit( 1 );
}
int ports[] = new int[args.length];
for (int i=0; i<args.length; ++i) {
ports[i] = Integer.parseInt( args[i] );
}
new MultiPortEcho( ports );
}
}