java socket(3)

 

import java.net.*;
import java.io.*;
public class PortScanner {
  public static void main(String args[]){
    String host="localhost";
    if(args.length>0)host=args[0];
    new PortScanner().scan(host);
  }
  public void scan(String host){
    Socket socket=null;
    for(int port=1;port<1024;port++){
      try {
          socket = new Socket(host, port);
          System.out.println("There is a server on port "+port);
      } catch (IOException e) {
          System.out.println("Can't connect to port "+port);
      } finally {
        try {
            if(socket!=null)socket.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
      }
    }
  }
}

 

 

 

package ch02;

import java.io.IOException;
import java.net.BindException;
import java.net.ConnectException;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.net.SocketAddress;
import java.net.SocketException;
import java.net.UnknownHostException;

public class ConnectTest {
    public static void main(String[] args) {
        String host = "www.baidu.com";
        int port = 80;
        if (args.length > 1) {
            host = args[0];
            port = Integer.parseInt(args[1]);
        }
        new ConnectTest().connect(host, port);
    }

    private void connect(String host, int port) {
        SocketAddress remoteAddress = new InetSocketAddress(host, port);
        Socket socket = null;
        String result;

        try {
            long begin = System.currentTimeMillis();
            socket = new Socket();
            socket.connect(remoteAddress, 1000);
            long end = System.currentTimeMillis();
            result = (end - begin) + "ms";
        } catch (BindException e) {
            result = "Local Address and port cant't be binded";
        } catch (UnknownHostException e) {
            result = "UnknownHost";
        } catch (ConnectException e) {
            result = "Connection Refused";
        } catch (SocketException e) {
            result = "Time out";
        } catch (IOException e) {
            result = "failure";
        } finally {
            if (socket != null)
                try {
                    socket.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
        }
        System.out.println(remoteAddress + ":" + result);
    }
}

Result：

 

 

package ch02;

import java.io.IOException;
import java.net.ServerSocket;

public class SimpleServer {

    /**
     * @param args
     * @throws IOException 
     * @throws InterruptedException 
     */
    public static void main(String[] args) throws IOException, InterruptedException {

        ServerSocket serverSocket=new ServerSocket(8000,2);
        new Thread().sleep(3600);
    }

}

package ch02;

import java.io.IOException;
import java.net.Socket;
import java.net.UnknownHostException;

public class SimpleClient {
    public static void main(String[] args) throws UnknownHostException, IOException {
        Socket socket1=new Socket("localhost",8000);
        System.out.println("first connect success");
        Socket socket2=new Socket("localhost",8000);
        System.out.println("second connect success");
        Socket socket3=new Socket("localhost",8000);
        System.out.println("third connect success");
    }
}