java 如何使用Java获取客户端的LAN IP？
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How to get the LAN IP of a client using Java?
提问by cragiz
How can i get the LAN IP-address of a computer using Java? I want the IP-address which is connected to the router and the rest of the network.
如何使用 Java 获取计算机的 LAN IP 地址？我想要连接到路由器和网络其余部分的 IP 地址。
I've tried something like this:
我试过这样的事情：
Socket s = new Socket("www.google.com", 80);
String ip = s.getLocalAddress().getHostAddress();
s.close();
This seem to work on some cases, but sometimes it returns the loopback-address or something completely different. Also, it requires internet connection.
这似乎在某些情况下有效，但有时它会返回环回地址或完全不同的东西。此外，它需要互联网连接。
Does anyone got a more accurate method of doing this?
有没有人有更准确的方法来做到这一点？
EDIT:Thought it would be better to ask here than in a comment..
编辑：认为在这里提问比在评论中更好..
What if you got many interfaces? For example, one for cable, one for wifi and one for virtual box or so. Is it impossible to actually see which one is connected to the network?
如果你有很多接口怎么办？例如，一个用于电缆，一个用于wifi，一个用于虚拟盒等等。真的不可能看到哪个连接到网络吗？
回答by Alexander Pogrebnyak
Try java.net.NetworkInterface
试试 java.net.NetworkInterface
import java.net.NetworkInterface;
...
for (
final Enumeration< NetworkInterface > interfaces =
NetworkInterface.getNetworkInterfaces( );
interfaces.hasMoreElements( );
)
{
final NetworkInterface cur = interfaces.nextElement( );
if ( cur.isLoopback( ) )
{
continue;
}
System.out.println( "interface " + cur.getName( ) );
for ( final InterfaceAddress addr : cur.getInterfaceAddresses( ) )
{
final InetAddress inet_addr = addr.getAddress( );
if ( !( inet_addr instanceof Inet4Address ) )
{
continue;
}
System.out.println(
" address: " + inet_addr.getHostAddress( ) +
"/" + addr.getNetworkPrefixLength( )
);
System.out.println(
" broadcast address: " +
addr.getBroadcast( ).getHostAddress( )
);
}
}
回答by Daniel
At first: There is no single address. Your machine has at least two adresses (127.0.0.1 on "lo" and maybe 192.168.1.1 on "eth1").
起初：没有单一地址。您的机器至少有两个地址（“lo”上的 127.0.0.1 和“eth1”上的 192.168.1.1）。
You want this: Listing network interfaces
你想要这个：列出网络接口
As you may expect, you cannot automatically detect which one is connected to any of your routers, since this needs potentially complex parsing of your routing tables. But if you just want any non-local address this should be enought. To be sure, try to use this at least one time on vista or Windows 7, since they add IPv6 addresses.
正如您所料，您无法自动检测哪个路由器连接到您的任何路由器，因为这可能需要对路由表进行复杂的解析。但是，如果您只想要任何非本地地址，这应该足够了。可以肯定的是，尝试在 vista 或 Windows 7 上至少使用一次，因为它们添加了 IPv6 地址。
import java.io.*;
import java.net.*;
import java.util.*;
import static java.lang.System.out;
public class ListNets
{
public static void main(String args[]) throws SocketException {
Enumeration<NetworkInterface> nets = NetworkInterface.getNetworkInterfaces();
for (NetworkInterface netint : Collections.list(nets))
displayInterfaceInformation(netint);
}
static void displayInterfaceInformation(NetworkInterface netint) throws SocketException {
out.printf("Display name: %s\n", netint.getDisplayName());
out.printf("Name: %s\n", netint.getName());
Enumeration<InetAddress> inetAddresses = netint.getInetAddresses();
for (InetAddress inetAddress : Collections.list(inetAddresses)) {
out.printf("InetAddress: %s\n", inetAddress);
}
out.printf("\n");
}
}
The following is sample output from the example program:
以下是示例程序的示例输出：
Display name: bge0
Name: bge0
InetAddress: /fe80:0:0:0:203:baff:fef2:e99d%2
InetAddress: /121.153.225.59
Display name: lo0
Name: lo0
InetAddress: /0:0:0:0:0:0:0:1%1
InetAddress: /127.0.0.1
回答by aioobe
This is a method I've used for a while. It includes a little hack to figure out the externally visible ip-address as well.
这是我使用了一段时间的方法。它包括一个小技巧来找出外部可见的 ip 地址。
private List<String> getLocalHostAddresses() {
List<String> addresses = new ArrayList<String>();
try {
Enumeration<NetworkInterface> e = NetworkInterface.getNetworkInterfaces();
while (e.hasMoreElements()) {
NetworkInterface ni = e.nextElement();
Enumeration<InetAddress> e2 = ni.getInetAddresses();
while (e2.hasMoreElements())
addresses.add(e2.nextElement().getHostAddress());
}
URL u = new URL("http://whatismyip.org");
BufferedReader in = new BufferedReader(new InputStreamReader(
u.openStream()));
addresses.add(in.readLine());
in.close();
} catch (Exception ignore) {
}
return addresses;
}
回答by andreasm
As Daniel already pointed out, you cannot know which interface is the one "connected". What if, for example, the computer has multiple network interface cards which are both connected to separate physical LANs?
正如丹尼尔已经指出的那样，您无法知道哪个接口是“连接”的。例如，如果计算机有多个网络接口卡，它们都连接到单独的物理 LAN，该怎么办？
Let the user decide which interface to use or try them all, depending on what your use case is.
让用户决定使用哪个界面或全部尝试，这取决于您的用例是什么。
回答by Mahmoud Al-Qudsi
try {
InetAddress addr = InetAddress.getLocalHost();
// Get IP Address
byte[] ipAddr = addr.getAddress();
// Get hostname
String hostname = addr.getHostName();
} catch (UnknownHostException e) {
}
