Socketソケットプログラミング

UDP

サービス側

public static void main(String[] args) throws IOException {
        //1. DatagramSocket
        DatagramSocket socket=new DatagramSocket(9999);
        // 
        byte[]buffer=new byte[1024];
        DatagramPacket packet=new DatagramPacket(buffer,buffer.length);
//2. 
        // 
       socket.receive(packet);// 

       String str=new String(buffer,0,packet.getLength(),"UTF-8");
        System.out.println(str);
        
       byte[]arr=" ".getBytes("UTF-8");
       DatagramPacket data=new DatagramPacket(buffer,packet.getLength(),packet.getAddress() ,packet.getPort() );

       socket.send(data);

    }

クライアント

public static void main(String[] args) throws IOException {
        DatagramSocket socket=new DatagramSocket();

        byte[]buffer=" ".getBytes("UTF-8");
        DatagramPacket packet=new DatagramPacket(buffer,buffer.length,InetAddress.getLoopbackAddress() ,9999);

        socket.send(packet);

        byte[]arr=new byte[1024];
        DatagramPacket data=new DatagramPacket(arr,arr.length);
        
        socket.receive(data);
        String str=new String(arr,0,data.getLength(),"UTF-8");
        System.out.println(str);
    }

TCP

サービス側

public static void main(String[] args) throws IOException {
        ServerSocket serversocket=new ServerSocket(8888);
        Scanner scanner=new Scanner(System.in);
        while(true){
            Socket socket=serversocket.accept();// ， 
            System.out.println(" "+socket.getInetAddress().getHostAddress() +":"+socket.getPort() );

            InputStream is=socket.getInputStream();
            InputStreamReader ism=new InputStreamReader(is,"UTF-8");
            BufferedReader reader=new BufferedReader(ism);

            OutputStream os=socket.getOutputStream();
            PrintStream out=new PrintStream(os,true,"UTF-8");

            String sc=reader.readLine();
            System.out.println(" ："+sc);
            System.out.println(" :");

            String response=scanner.nextLine() ;
            out.println(response);
            socket.close();
        }
    }

クライアント

 public static void main(String[] args) throws IOException {
        Scanner scanner = new Scanner(System.in);
        Socket socket = new Socket();
        byte[] arr = {(byte) 127, (byte) 0, (byte) 0, (byte) 1};
        InetAddress intadd = InetAddress.getByAddress(arr);
        SocketAddress address = new InetSocketAddress(intadd, 8888);
        socket.connect(address);
        while (true) {
            OutputStream os = socket.getOutputStream();
            PrintStream out = new PrintStream(os, true, "UTF-8");

            String request = scanner.nextLine();
            out.println(request);
            out.flush();

            InputStream is = socket.getInputStream();
            BufferedReader reader = new BufferedReader(new InputStreamReader(is));
            String str=reader.readLine();
            System.out.println(str);
        }
        }