Question

对于我的班级项目，我有以下问题。我能够接收客户信息并将信息重新发送给相应的客户。但是，我无法将每个客户的信息发送给其他所有客户端（广播？）。我还需要实现给定的功能。任何帮助，将不胜感激。

目标是通过UDP设计和实现简单的应用层协议促进高可用性群集（HAC）。 HAC有一套检测故障转移的机制，网络/节点故障等，以便将流量重新路由到可用系统。在这个项目中您将不会处理诸如如何执行一致的故障转移或高的问题可用性分布式管理程序但是，您的任务是设计和实现协议维护整个集群中的上行节点信息。您设计的协议应执行以下功能：

a）定期检测节点故障

b）通知网络中的其他节点有关故障（对等选项）

c）能够检测故障节点何时恢复生命

d）通知其他节点有关新节点的可用性

客户类：

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.net.*;
import java.util.Random;

public class UDPClient 
{
    DatagramSocket Socket;

    public UDPClient() 
    {

    }

    public void createAndListenSocket() throws ClassNotFoundException, InterruptedException 
    {
        try 
        {
            Socket = new DatagramSocket();
            InetAddress IPAddress = InetAddress.getByName("localhost");
            byte[] incomingData = new byte[1024];
            String sentence = "Client 1 is up";
            byte[] data = sentence.getBytes();
            boolean flag = true; 
            CreatePacket packet = new CreatePacket(data, flag, data.length);

         while(true)
         {            
            //Serialize to send          
             Random rnd = new Random();
             int timeout = rnd.nextInt(30);
             Thread.sleep(timeout*1000); 

            ByteArrayOutputStream buffer = new ByteArrayOutputStream();
            ObjectOutputStream out = new ObjectOutputStream(buffer);
            out.writeObject(packet);
            out.close();
            buffer.close();

            DatagramPacket sendPacket = new DatagramPacket(buffer.toByteArray(), buffer.size(), IPAddress, 9876);
            Socket.send(sendPacket);
            System.out.println("Message sent from client");           

            //Deserialize and receive packet from server
            DatagramPacket incomingPacket = new DatagramPacket(incomingData, incomingData.length);
            Socket.receive(incomingPacket);

            ByteArrayInputStream bis = new ByteArrayInputStream(incomingPacket.getData());
            ObjectInputStream in = new ObjectInputStream(bis);
            Object receivedPacket = in.readObject();
            in.close();

            InetAddress IPAddress1 = incomingPacket.getAddress();
            int port = incomingPacket.getPort();

            System.out.println();
            System.out.println("Response from server: ");
            System.out.println("Message : " + receivedPacket.toString());
            System.out.println("Client IP: "+ IPAddress1.getHostAddress());
            System.out.println("Client port: "+ port);                       
         }           
        }
        catch (UnknownHostException e) 
        {
            e.printStackTrace();
        } 
        catch (SocketException e) 
        {
            e.printStackTrace();
        } 
        catch (IOException e) 
        {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) throws Exception 
    {
        UDPClient client = new UDPClient();
        client.createAndListenSocket(); 
    }
}

服务器代码：

public class UDPServer 
{
    DatagramSocket socket = null;

    public UDPServer() 
    {

    }
    public void createAndListenSocket() throws ClassNotFoundException 
    {
        try 
        {
            socket = new DatagramSocket(9876);
            byte[] incomingData = new byte[1024];

            while (true) 
            {

                DatagramPacket incomingPacket = new DatagramPacket(incomingData, incomingData.length);
                socket.receive(incomingPacket);
                CreatePacket toSendPacket = new CreatePacket(incomingData, incomingData.length);
                ArrayList <CreatePacket> clients = new ArrayList<CreatePacket>(4);

               ByteArrayInputStream bis = new ByteArrayInputStream(incomingPacket.getData());
               ObjectInputStream in = new ObjectInputStream(bis);
               Object receivedPacket = in.readObject();
               in.close();

               clients.add(toSendPacket); 

               InetAddress IPAddress = incomingPacket.getAddress();
               int port = incomingPacket.getPort();

               System.out.println(); 
               System.out.println("" + receivedPacket.toString());
               System.out.println("Client IP: "+ IPAddress.getHostAddress());
               System.out.println("Client port: "+ port);

               DatagramPacket replyPacket = new DatagramPacket(incomingData, incomingData.length, IPAddress, port);
               Thread.sleep(10*1000);
                socket.send(replyPacket);
                //socket.close();
            }
        } 
        catch (SocketException e) 
        {
            e.printStackTrace();
        } 
        catch (IOException i) 
        {
            i.printStackTrace();
        } 
        catch (InterruptedException e) 
        {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) throws ClassNotFoundException, IOException 
    {
        UDPServer server = new UDPServer();
        server.createAndListenSocket();
    }
}

Answer 1

你想要 1 - 客户端在服务器启动/活动时向服务器发送消息 2 - 如果服务器收到信号，它会向所有客户端发送一些消息吗？

我不确定，但你可以试试这个， InetAddress IPAddress =incomingPacket.getAddress(); int port =incomingPacket.getPort(); 当您获取一个客户端的 IP 地址时，您可以存储服务器端所有客户端的地址，这些客户端在列表或数组中处于启动状态/活动状态。然后，如果您收到到服务器的信号，请使用该列表发送响应。您需要根据 up/alive 客户端更新列表。

利用Java促进高可用性集群（HAC）

1 个答案: