java (多网卡环境下)发送组播广播(multicast/broadcast)失败问题

	/**
	 * 向指定的组播或广播地址和端口发送组播数据
	 * @param group 组播或广播地址
	 * @param port 端口
	 * @param message 发送的数据
	 * @param ttl  time-to-live for multicast packets 
	 * @param nic 指定发送数据的网卡
	 * @throws IOException
	 */
	public static void sendMulticast(InetAddress group,int port,byte[] message, Integer ttl,NetworkInterface nic) throws IOException{
		checkArgument(null != group,"group is null");
		// 如果地址不是组播或广播地址则抛出异常
		checkArgument(group.isMulticastAddress() || isBroadcast(group),"group %s is not a multicast or broadcast address",group);
		checkArgument(message != null && message.length > 0,"message is null or empty");
		checkArgument(null != nic,"nic is null");
		// 获取网卡的绑定的所有IP地址枚举对象
		Enumeration<InetAddress> nifAddresses = nic.getInetAddresses();
		if(!nifAddresses.hasMoreElements()){
			System.out.printf("NOT ADDRESS ON %sn",nic.toString());
			return;
		}
		// 从网卡上绑定的IP地址创建的InetSocketAddress 对象
		InetSocketAddress inetAddr= new InetSocketAddress(nifAddresses.nextElement(),0);

		DatagramSocket ds = null;
		try {
			if(group.isMulticastAddress()){
				// MulticastSocket 绑定到指定的网卡
				@SuppressWarnings("resource")
				MulticastSocket ms =  new MulticastSocket(inetAddr);
				if(ttl != null){
					ms.setTimeToLive(ttl);
				}
				ds = ms;
			}else{
				// DatagramSocket绑定到指定的网卡
				ds = new DatagramSocket(inetAddr);
				ds.setBroadcast(true);
			}
			
			ds.send(new DatagramPacket(message, message.length,group,port));
		} finally {
			if(ds != null){
				ds.close();
			}
		}
	}
	/**
	 * 向指定的组播或广播地址和端口发送组播数据
	 * @param group 组播或广播地址
	 * @param port 端口
	 * @param message 发送的数据
	 * @param ttl  time-to-live for multicast packets 
	 * @throws IOException
	 */
	public static void sendMulticast(InetAddress group,int port,byte[] message, Integer ttl) throws IOException{
		checkArgument(null != group,"group is null");
		// 如果地址不是组播或广播地址则抛出异常
		checkArgument(group.isMulticastAddress() || isBroadcast(group),"group %s is not a multicast or broadcast address",group);
		checkArgument(message != null && message.length > 0,"message is null or empty");
		// 遍历所有物理网卡，将数据在每个网卡上发送一次
		for(NetworkInterface nic:getNICs(Filter.UP,Filter.PHYICAL_ONLY)){
			sendMulticast(group,port,message,ttl,nic);
		}
	}
	/**
	 * 判断一个地址是否为广播地址(255.255.255.255)
	 * @param addr
	 * @return
	 */
	public static boolean isBroadcast(InetAddress addr){
		return addr.getHostAddress().equals("255.255.255.255");
	}

	/**
	 * socket初始化
	 * @return 当前对象
	 * @throws IOException 创建组播对象({@link MulticastSocket})时出错
	 */
	public MultiCastDispatcher init() throws IOException{
		if(null == datagramSocket){
			if(NetworkUtil.isBroadcast(group)){
				datagramSocket = new DatagramSocket(port);
				datagramSocket.setBroadcast(true);
			}else{
				MulticastSocket multicastSocket = new MulticastSocket(port);
				// 遍历所有物理网卡，对每块网卡执行joinGroup
				for(NetworkInterface nic:NetworkUtil.getNICs(Filter.UP,Filter.PHYICAL_ONLY)){
					InetSocketAddress inetAddr= new InetSocketAddress(group,0);
					multicastSocket.joinGroup(inetAddr,nic);
				}
				this.datagramSocket = multicastSocket;
			}
		}
		return this;
	}
	/**
	 * 循环接收group,port指定的组播地址发送的数据并交给{@link #processor}处理
	 */
	@Override
	public void run() {
		stopListener = Boolean.FALSE;
		DatagramPacket packet = new DatagramPacket(message, message.length);
		try {
			while(!Boolean.TRUE .equals(stopListener)){
				try {
					checkArgument(datagramSocket != null,"multicastSocket is uninitizlied");
					datagramSocket.receive(packet);
					byte[] recevied = new byte[packet.getLength()];
					System.arraycopy(message, 0, recevied, 0, packet.getLength());
					// 处理收到的广播/组播数据
					if(!processor.apply(recevied)){
						break;
					}
				} catch (Exception e) {
					if(!onerr.apply(e)){
						break;
					}
				}
			}
		} finally {
			try {
				if(datagramSocket instanceof MulticastSocket){
					// 遍历所有物理网卡，对每块网卡执行leaveGroup
					for(NetworkInterface nic:NetworkUtil.getNICs(Filter.UP,Filter.PHYICAL_ONLY)){
						InetSocketAddress inetAddr= new InetSocketAddress(group,0);
						((MulticastSocket) datagramSocket).leaveGroup(inetAddr,nic);
					}
				}
			} catch (IOException e) {
				e.printStackTrace();
			}
			datagramSocket.close();
			datagramSocket = null;
			stopListener = null;
		}				
	}