java socket 통신 예제

소켓통신을 통해 클라이언트 - > 서버로 메세지를 보내는 간단한 예제 

 

 

서버 - EchoServer.java

package sample;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;

public class EchoServer {
    public static void main(String[] args) throws IOException {
        ServerSocket serverSocket = null;

        try {
            serverSocket = new ServerSocket(10007);
        } catch (IOException e) {
            System.err.println("Could not listen on port: 10007.");
            System.exit(1);
        }

        Socket clientSocket = null;
        System.out.println("Waiting for connection.....");

        try {
            clientSocket = serverSocket.accept();
        } catch (IOException e) {
            System.err.println("Accept failed.");
            System.exit(1);
        }

        System.out.println("Connection successful");
        System.out.println("Waiting for input.....");

        PrintWriter out = new PrintWriter(clientSocket.getOutputStream(), true);
        BufferedReader in = new BufferedReader(new InputStreamReader(
                clientSocket.getInputStream()));

        String inputLine;

        while ((inputLine = in.readLine()) != null) {
            System.out.println("Server: " + inputLine);
            out.println(inputLine);

            if (inputLine.equals("Bye."))
                break;
        }

        out.close();
        in.close();
        clientSocket.close();
        serverSocket.close();
    }
}

 

 

클라이언트 - EchoClient.java

 

package sample;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;
import java.net.UnknownHostException;

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

        String serverHostname = new String("127.0.0.1");

        if (args.length > 0)
            serverHostname = args[0];
        System.out.println("Attemping to connect to host " + serverHostname
                + " on port 10007.");

        Socket echoSocket = null;
        PrintWriter out = null;
        BufferedReader in = null;

        try {
            // echoSocket = new Socket("taranis", 7);
            echoSocket = new Socket(serverHostname, 10007);
            out = new PrintWriter(echoSocket.getOutputStream(), true);
            in = new BufferedReader(new InputStreamReader(
                    echoSocket.getInputStream()));
        } catch (UnknownHostException e) {
            System.err.println("Don't know about host: " + serverHostname);
            System.exit(1);
        } catch (IOException e) {
            System.err.println("Couldn't get I/O for " + "the connection to: "
                    + serverHostname);
            System.exit(1);
        }

        BufferedReader stdIn = new BufferedReader(new InputStreamReader(
                System.in));
        String userInput;

        System.out.print("input: ");
        while ((userInput = stdIn.readLine()) != null) {
            out.println(userInput);
            System.out.println("echo: " + in.readLine());
            System.out.print("input: ");
        }

        out.close();
        in.close();
        stdIn.close();
        echoSocket.close();
    }
}