From 0c46bb587e8df62e2132b3d742c7465d45bf7e0a Mon Sep 17 00:00:00 2001
From: kyoohyunlee <khyhlee@naver.com>
Date: Tue, 29 Jul 2025 16:50:52 +0900
Subject: [PATCH] =?UTF-8?q?Java=20Network:=20TCP=20=EC=84=9C=EB=B2=84=20?=
 =?UTF-8?q?=EB=8F=99=EC=8B=9C=EC=9A=94=EC=B2=AD=20=EC=B2=98=EB=A6=AC(?=
 =?UTF-8?q?=EC=8A=A4=EB=A0=88=EB=93=9C=20=ED=92=80)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../req_execution_threadpool/EchoSercer.java  | 105 ++++++++++++++++++
 1 file changed, 105 insertions(+)
 create mode 100644 src/step06_network/req_execution_threadpool/EchoSercer.java

diff --git a/src/step06_network/req_execution_threadpool/EchoSercer.java b/src/step06_network/req_execution_threadpool/EchoSercer.java
new file mode 100644
index 0000000..980fea1
--- /dev/null
+++ b/src/step06_network/req_execution_threadpool/EchoSercer.java
@@ -0,0 +1,105 @@
+package step06_network.req_execution_threadpool;
+
+import javax.xml.crypto.Data;
+import java.io.DataInputStream;
+import java.io.DataOutput;
+import java.io.DataOutputStream;
+import java.io.IOException;
+import java.lang.reflect.Executable;
+import java.net.InetSocketAddress;
+import java.net.ServerSocket;
+import java.net.Socket;
+import java.util.Scanner;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+
+public class EchoSercer {
+    private static ServerSocket serverSocket = null;
+    //10개의 스레드로 요청을 처리하는 스레드풀 생성
+    private static ExecutorService executorService =
+            Executors.newFixedThreadPool(10);
+
+    public static void main(String[] args) {
+        System.out.println("------------------------------------------");
+        System.out.println("서버를 종료하려면 q를 입력하고 Enter키를 입력하세요.");
+        System.out.println("------------------------------------------");
+
+        //TCP 서버 시작
+        startServer();
+
+        //키보드 입력
+        Scanner sc = new Scanner(System.in);
+        while(true){
+            String key = sc.nextLine();
+            if(key.toLowerCase().equals("q")){
+                break;
+            }
+        }
+        sc.close();
+
+        //TCP 서버 종료
+        stopServer();
+    }
+
+    public static void startServer(){
+        //작업 스레드 정의
+        Thread thread = new Thread(){
+            @Override
+            public void run(){
+                try{
+                    //serverSocket 생성, Port 바인딩
+                    serverSocket = new ServerSocket(50001);
+                    System.out.println("[서버] 시작됨\n");
+
+                    //연결 수락 및 데이터 통신
+                    while (true){
+                        //연결 수락
+                        Socket socket = serverSocket.accept();
+                        /**
+                         * 작업 큐에 처리 작업 넣기
+                         * RUnnable은 함수형 인터페이스라 람다식으로 표현
+                         */
+                        executorService.execute(() -> {
+                            try{
+                                //연결된 클라이언트 정보 얻기
+                                InetSocketAddress isa =
+                                        (InetSocketAddress) socket.getRemoteSocketAddress();
+                                System.out.println("[서버] "+isa.getHostName()+"의 연결 요청 수락");
+
+                                //데이터 받기
+                                DataInputStream dis = new DataInputStream(
+                                        socket.getInputStream());
+                                String message = dis.readUTF();
+
+                                //데이터 보내기
+                                DataOutputStream dos =
+                                        new DataOutputStream(socket.getOutputStream());
+                                dos.writeUTF(message);
+                                dos.flush();
+                                System.out.println("[서버] 받은 데이터를 다시 보냄 "+message);
+
+                                //연결 끊기
+                                socket.close();
+                                System.out.println("[서버] "+isa.getHostName()+"의 연결을 끊음\n");
+                            }catch (IOException e){
+                            }
+                        });
+                    }
+                }catch (IOException e){
+                }
+            }
+        };
+        //스레드 시작
+        thread.start();
+    }
+
+    public static void stopServer(){
+        try{
+            //ServerSocket을 닫고 Port 언 바인딩
+            serverSocket.close();
+            executorService.shutdownNow(); //스레드풀 종료
+            System.out.println("[서버] 종료됨 ");
+        }catch (IOException e){
+        }
+    }
+}