20일차1 c/s programming, TCP통신 복습.

20일차 오전.

c/s (client , server 간 network programming)

프로토콜의 종류.

* UDP : packit 을 이용하는 1:1 개념, brodcasting service 느낌.

* TCP : c/s 의 socket을 열어 통신하는 방법.

기본적인 TCP 통신의 예제를 통해 알아보자.

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* 기본적인 생성자호출 부분은 생략.

Client

package hb.net.java_20151217; import java.io.BufferedReader; import java.io.BufferedWriter; import java.io.InputStream; import java.io.InputStreamReader; import java.io.OutputStream; import java.io.OutputStreamWriter; import java.net.Socket; public class ExClient { Socket socket ; InputStream ins; OutputStream outs; public ExClient(){ try { //localhost , 127.0.0.1 이 두가지는 이 컴퓨터 내에서만 작업할 때 socket = new Socket("192.168.0.42", 3000); System.out.println("어허~ 소켓부분"); String str = "하잇"; //to server outs = socket.getOutputStream(); OutputStreamWriter osw = new OutputStreamWriter(outs); BufferedWriter bw = new BufferedWriter(osw); bw.write(str); bw.newLine(); bw.flush(); System.out.println("보냈다! " + bw); //from server ins = socket.getInputStream(); InputStreamReader isr = new InputStreamReader(ins); BufferedReader br = new BufferedReader(isr); String stt = br.readLine(); System.out.println("읽었다."+ stt); } catch (Exception e) {e.printStackTrace();} }//constructor }

Server

package hb.net.java_20151217; import java.io.BufferedReader; import java.io.BufferedWriter; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.OutputStream; import java.io.OutputStreamWriter; import java.net.ServerSocket; import java.net.Socket; public class ExServer { ServerSocket server; Socket socket; InputStream ins; OutputStream outs; public ExServer(){ try { System.out.println("실행"); server = new ServerSocket(3000); /** 중요. *생성자 안에서 소켓을 생성했기 때문에 소켓이 한번만 리턴된다. *다중접속에서는 반복시켜야한다. **/ } catch (Exception e) {e.printStackTrace();} }//constructor public void StartServer(){ System.out.println("실행한다"); try { socket = server.accept(); System.out.println("accpet"); //수신 BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream())); String data = br.readLine(); System.out.println("데이터를 읽었다.2 : "+data); //송신(전송) BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream())); bw.write(data); bw.newLine(); bw.flush(); System.out.println("데이터를 보냈다.3 : "+data); } catch (IOException e) {e.printStackTrace();} } }