创建套接字客户端

import java.io.*;

import java.net.*;
//from n o w    j a v a  . c o m

public class EchoClient {

    public static void main(String[] args) throws IOException {


        if (args.length != 2) {

            System.err

                    .println("Usage: java EchoClient <host name> <port number>");

            System.exit(1);

        }


        String hostName = args[0];

        int portNumber = Integer.parseInt(args[1]);


        try (Socket echoSocket = new Socket(hostName, portNumber);

                PrintWriter out = new PrintWriter(

                        echoSocket.getOutputStream(), true);

                BufferedReader in = new BufferedReader(

                        new InputStreamReader(echoSocket.getInputStream()));

                BufferedReader stdIn = new BufferedReader(/*来 自 时 代 J a v a 公 众 号*/

                        new InputStreamReader(System.in))) {

            String userInput;

            while ((userInput = stdIn.readLine()) != null) {

                out.println(userInput);

                System.out.println("echo: " + in.readLine());

            }

        } catch (UnknownHostException e) {

            System.err.println("Don't know about host " + hostName);

            System.exit(1);

        } catch (IOException e) {

            System.err.println("Couldn't get I/O for the connection to "

                    + hostName);

            System.exit(1);

        }

    }

}