问题描述
在我的程序中,我发送 UDP 广播并对它们做出反应.我需要一种方法来忽略 我 发出的 UDP 广播,但对不是来自我的机器的广播做出反应.
In my program I'm sending out UDP broadcasts and reacting to them. I need a way to ignore the UDP broadcasts that I send out, but react to ones that aren't from my machine.
我确实尝试过使用:if (NetworkInterface.getByInetAddress(packet.getAddress()) != null)
但这在某些情况下会产生 IOExceptions(java.net.SocketException: no network interface is bound to such an IP address)
I did try using:if (NetworkInterface.getByInetAddress(packet.getAddress()) != null)
but this generated IOExceptions in some cases (java.net.SocketException: no network interface is bound to such an IP address)
有人有什么想法吗?
还有:我的套接字上的 getInetAddress() 抛出 NullPointerException
Also:getInetAddress() on my socket throws a NullPointerException
推荐答案
我觉得javadoc和NetworkInterface getByInetAddress()
的实际实现有点出入.javadoc 似乎建议 getByInetAddress 如果未找到匹配项将返回 null,但实现要么返回匹配项,要么抛出 SocketException.
I think there's a little discrepancy between the javadoc and the actual implementation of NetworkInterface getByInetAddress()
. The javadoc seems to suggest that getByInetAddress would return null if no match was found, yet the implementation either returns a match, either throws a SocketException.
public static NetworkInterface getByInetAddress(InetAddress addr)
throws SocketException
返回:一个 NetworkInterface 或 如果没有具有指定 IP 地址的网络接口,则返回 null.
Returns: A NetworkInterface or null if there is no network interface with the specified IP address.
public static NetworkInterface getByInetAddress (InetAddress addr)
throws SocketException
{
if (networkInterfaces == null)
networkInterfaces = getRealNetworkInterfaces ();
for (Enumeration interfaces = networkInterfaces.elements ();
interfaces.hasMoreElements (); )
{
NetworkInterface tmp = (NetworkInterface) interfaces.nextElement ();
for (Enumeration addresses = tmp.inetAddresses.elements ();
addresses.hasMoreElements (); )
{
if (addr.equals ((InetAddress) addresses.nextElement ()))
return tmp;
}
}
throw new SocketException (
"no network interface is bound to such an IP address");
}
我建议要么捕获异常并将其视为来自第 3 方的答案,要么使用 getNetworkInterfaces()
方法重新实现它.
I suggest to either catch the exception and treat it as an answer from a 3rd party, either re-implement it using the getNetworkInterfaces()
method.
这篇关于在 Java 中忽略您自己的 UDP 广播的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!