如何通过互联网从Java客户端连接服务器？

Question

我在java服务器和客户端创建了两个程序，我通过localhost连接，但我想通过互联网连接全世界的客户端。

public class Client {

    public static void main(String[] args) throws UnknownHostException, IOException {

        Socket socket = new Socket("localhost", 1234);

        OutputStream outputStream = socket.getOutputStream();
        DataOutputStream dataOutputStream = new DataOutputStream(outputStream);

        dataOutputStream.writeInt(Integer.parseInt(args[0]));

        InputStream inputStream = socket.getInputStream();
        DataInputStream dataInputStream = new DataInputStream(inputStream);

        System.out.println(dataInputStream.readUTF());

    }

}

public class Server {

    public static void main(String[] args) throws IOException {

        ServerSocket serverSocket = new ServerSocket(1234);

        while(true) {

            Socket socket = serverSocket.accept();

            InputStream inputStream = socket.getInputStream();
            DataInputStream dataInputStream = new DataInputStream(inputStream);

            int a = dataInputStream.readInt();

            OutputStream outputStream = socket.getOutputStream();
            DataOutputStream dataOutputStream = new DataOutputStream(outputStream);


            if(a == 1698) 
                dataOutputStream.writeUTF("Welcome Salman");

            else if(a == 1700) 

                dataOutputStream.writeUTF("Welcome Wajeh");

            else if(a == 1694) 

                dataOutputStream.writeUTF("Welcome Farhan");

            else 
                dataOutputStream.writeUTF("Wrong Roll No");

        }

    }

}

Answer 1

与浏览器连接到SO的方式相同，您应该获取服务器的IP地址并连接到它，这可以通过DNS完成。

Answer 2

您可以通过替换该行的参数来执行此操作：

Socket socket = new Socket("localhost", 1234);

进入服务器的公共IP地址和运行应用程序的端口。