DatagramSocket可以接收多播数据包吗 [英] Can DatagramSocket Receive multicast Packets

问题描述

我有一个在线程中运行的代码，用于将DatagramPacket发送到计算机中每个NetworkInterface的广播地址以及多播组.如下:

I have a code that runs in a thread, which i use to send a DatagramPacket to broadcast address of each NetworkInterface in the computer and also to a multicast group. It is as follows:

try {
    String decl="Mymessage";
    DatagramPacket ackdp;
    while(true)
        {
        Thread.sleep(3000);
        //First sending multicast (not broadcast) packet to a multicast group
        //231.26.179.75:37486
        ackdp=new DatagramPacket(s.getBytes(),s.length(),multicastGroup,port);
        BroadcastSocket.send(ackdp);
        //Now sending same message to broadcast address of each of the n/w interfaces
        Enumeration nwInterfaces = NetworkInterface.getNetworkInterfaces();
        while(nwInterfaces.hasMoreElements())
                {
                NetworkInterface ni=(NetworkInterface) nwInterfaces.nextElement();
                if(ni.isLoopback()||!ni.isUp())
                        continue;
                for(InterfaceAddress ifa:ni.getInterfaceAddresses())
                        {
                        InetAddress broadcastIP=ifa.getBroadcast();
                        if(broadcastIP==null)
                                continue;
                        ackdp=new DatagramPacket(s.getBytes(),s.length(),broadcastIP,port);
                        BroadcastSocket.send(ackdp);
                        //port is same here :37486 (ip varies with network interface)
                        }
                }
        }
    } catch (Exception ex) {ex.printStackTrace();}

我的问题是:我可以使用相同的DatagramSocket接收(组播和广播)数据包吗?请注意，两者都发送到同一端口.我应该在37486端口上打开MulticastSocket还是DatagramSocket来接收两个数据包吗?

My question is: Can i receive both (multicast and broadcast) packets using same DatagramSocket? Note that both are sent to same port. Should i open a MulticastSocket or a DatagramSocket at the port 37486 to receive both packets?

(数据包是从PC发送的，但在Android上已接收)

推荐答案

DatagramSocket是否可以接收多播数据包

Can DatagramSocket receive multicast Packets

否，因为它无法加入多播组.

No, because it can't join the multicast group.

您没有要求，但是为了完整性:

You didn't ask, but for completeness:

DatagramSocket是否可以发送多播数据包

Can DatagramSocket send multicast Packets

是的

MulticastSocket可以接收数据报(非多播)数据包

Can MulticastSocket receive datagram (non-multicast) packets

是的

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