Java如何使伺服器允許連線到通訊端埠？

在Java程式設計中，如何使伺服器允許連線到通訊端埠？

以下範例顯示如何使伺服器通過使用ServerSocket類的server.accept()方法和Socket類的sock.getInetAddress()方法來允許連線到通訊端埠：`1234。

package com.yiibai;

import java.io.IOException;
import java.net.InetAddress;
import java.net.ServerSocket;
import java.net.Socket;

public class ConnectingSocket {
    public static void main(String[] args) {
      try {
         ServerSocket server = new ServerSocket(12345);
         while (true) {
            System.out.println("Listening");
            Socket sock = server.accept();
            InetAddress addr = sock.getInetAddress();
            System.out.println("Connection made to " + addr.getHostName() + " (" + addr.getHostAddress() + ")");
            pause(5000);
            sock.close();
         }
      } catch (IOException e) {
         System.out.println("Exception detected: " + e);
      }
   }

    private static void pause(int ms) {
        try {
            Thread.sleep(ms);
        } catch (InterruptedException e) {
        }
    }
}

上述程式碼範例將產生以下結果 -

Listening
Connection made to 127.0.0.1 (127.0.0.1)
Listening

用戶端程式碼參考如下 -

package com.yiibai;

import java.io.IOException;
import java.net.InetAddress;
import java.net.Socket;
import java.net.SocketException;
import java.net.UnknownHostException;

public class SocketClient {
    public static void main(String[] args) {
        try {
            //InetAddress addr = InetAddress.getByName("127.0.0.1");
            Socket theSocket = new Socket("127.0.0.1", 12345);
            System.out.println("Connected to " + theSocket.getInetAddress() + " on port " + theSocket.getPort()
                    + " from port " + theSocket.getLocalPort() + " of " + theSocket.getLocalAddress());
        } catch (UnknownHostException e) {
            System.err.println("I can't find " + e);
        } catch (SocketException e) {
            System.err.println("Could not connect to " + e);
        } catch (IOException e) {
            System.err.println(e);
        }
    }
}