Creating java sockets behind proxy servers.

Question

Hi,
I am trying to create a socket to an external server(i.e. a public server) from behind a proxy firewall, but the socket creation statement throws an IO exception. Can someone please let me know how to create sockets using proxy servers.
TIA
Shishir

Answer 1

I tried using java.net.Proxy for the connection. But the socket to the proxy itself is not getting created. It throws the IllegalArgumentException.
import java.io.*;
import java.net.*;
import java.net.Proxy.Type;
public class Client {
static Socket proxSocket = null;
static PrintWriter out = null;
static BufferedReader in = null;
public static void main(String[] args) throws IOException {    
try {
System.out.println("Trying to create socket");
InetSocketAddress proxyadd = new InetSocketAddress(InetAddress.getByName("148.87.19.20"),80);
Proxy ps = new Proxy(Proxy.Type.HTTP,proxyadd);
Socket proxSocket = new Socket(ps);
out = new PrintWriter(proxSocket.getOutputStream(), true);
in = new BufferedReader(new InputStreamReader(
proxSocket.getInputStream()));
} catch (UnknownHostException e) {
System.err.println("Don't know about host: ...");
System.exit(1);
} catch (IOException e) {
System.err.println("Couldn't get I/O for "
+ "the connection to: ...");
System.exit(1);
catch(IllegalArgumentException e)
System.err.println("Unable to describe the proxy.");
System.exit(1);
}