InputStream 과 OutputStream

InputStream input  = socket.getInputStream();
OutputStream output = socket.getOutputStream();

while(true) {
	//5. 데이터 읽기
	byte buffer[] = new byte[256];

	int readByteCount = input.read(buffer);//blocking.

	if(readByteCount == -1) {
		// 클라이언트 정상종료 한 경우
		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
	output.write(data.getBytes("utf-8"));

	}