포스코DX X 비트교육센터 6기 - 소켓통신

package test;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.InetSocketAddress;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketException;

public class TCPServer {

	public static void main(String[] args) {
		ServerSocket serverSocket = null;
		
		try {
			//1. Server Socket 생성
			serverSocket = new ServerSocket();
			
			//2. 바인딩(Binding)
			// Socket에 InetSocketAddress(IPAddresss + port)를 바인딩 한다.
			// IPAddress: 0.0.0.0: 특정 호스트 IP에 바인딩 하지 않는다.
			// IPAddress : 내가 접속할 IP주소 0.0.0.0 - 특정 호스트 IP에 바인딩하지 않는다, 아무데서나 접근 가능
			serverSocket.bind(new InetSocketAddress("0.0.0.0", 5000), 10);
			
			//3. accept
			Socket socket = serverSocket.accept(); // blocking
			
			try {
				InetSocketAddress remoteInetSocketAddress = (InetSocketAddress)socket.getRemoteSocketAddress();
				String remoteHostAddress = remoteInetSocketAddress.getAddress().getHostAddress();
				int remotePort = remoteInetSocketAddress.getPort();
				System.out.println("[server] connected by client[" + remoteHostAddress + ":" + remotePort + "]");
				
				//4.  IO Stream 받아오기
				OutputStream os = socket.getOutputStream();
				InputStream is = socket.getInputStream();
				
				while(true) {
					//5. 데이터읽기
					byte[] buffer = new byte[256]; 
					int readByteCount = is.read(buffer);  // blocking
					
					if(readByteCount == -1) {
						// 클라이언트가 정상적으로 종료(close() 호출)
						System.out.println("[server] closed by client");
						break;
					}
					
					String data = new String(buffer, 0, readByteCount, "utf-8");
					System.out.println("[server] received:" + data);
					
					//6. 데이터 쓰기
					os.write(data.getBytes("utf-8"));
				}				
			} catch(SocketException e) {
				System.out.println("[server] suddenly closed by client");
			} catch (IOException e) {
				System.out.println("[server] error:" + e);
			} finally {
				try {
					if(socket != null && !socket.isClosed()) {
						socket.close();
					}
				} catch(IOException e) {
					e.printStackTrace();
				}
			}
			
		} catch (IOException e) {
			System.out.println("[server] error:" + e);
		} finally {
			try {
				if(serverSocket != null && !serverSocket.isClosed()) {
					serverSocket.close();
				}
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
		

	}

}

package thread;

public class threadEx01 {
	public static void main(String[] args) {
		//for(int i = 0 ; i <10; i++) {
		//	System.out.print(i);
		//}
		
		//Thread를 쓰면, 자리 선점하는데 시간이 걸려서 밀린다. 
		//출력 결과 : abc0123456789defghijklmnopqrstuvwxyz
		new DigitalThread().start();
		
		for(char c= 'a'; c<= 'z'; c++) {
			System.out.print(c);
			
			try {
				//sleep을 통해 이 두 가지 for문을 섞어줌.
				Thread.sleep(1000);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
		}
	}
}

package thread;

public class DigitalThread extends Thread {

	@Override
	public void run() {
		for(int i = 0 ; i <10; i++) {
			System.out.print(i);
			
			try {
				Thread.sleep(1000);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
		}
		
	}

	

}