web网络 - 获取本机网卡ip地址 - 《编程》

pfmiles ```java import java.net.InetAddress; import java.net.NetworkInterface; import java.net.SocketException; import java.util.Enumeration; import java.util.HashSet; import java.util.Iterator; import java.util.Set;

/**

获取本地ip的工具
@author pf-miles
@since 2014-11-25 */ public class LocalIpAddressUtil {

/**
- 获取本地ip地址，有可能会有多个地址, 若有多个网卡则会搜集多个网卡的ip地址 */ public static Set resolveLocalAddresses() { Set addrs = new HashSet(); Enumeration ns = null; try {
```
 ns = NetworkInterface.getNetworkInterfaces();
```
  } catch (SocketException e) {
```
 // ignored...
```
  } while (ns != null && ns.hasMoreElements()) {
```
 NetworkInterface n = ns.nextElement();
 Enumeration<InetAddress> is = n.getInetAddresses();
 while (is.hasMoreElements()) {
     InetAddress i = is.nextElement();
     if (!i.isLoopbackAddress() && !i.isLinkLocalAddress() && !i.isMulticastAddress()
         && !isSpecialIp(i.getHostAddress())) addrs.add(i);
 }
```
  } return addrs; }
  
  public static Set resolveLocalIps() { Set addrs = resolveLocalAddresses(); Set ret = new HashSet(); for (InetAddress addr : addrs)
```
 ret.add(addr.getHostAddress());
```
  return ret; }
  
  /**
- 取得当前机器的address信息，若有多个则随机选一个 */ public static InetAddress resolveLocalAddress() { Set addrs = resolveLocalAddresses(); if (addrs != null && !addrs.isEmpty()) return addrs.iterator().next(); return null; }
  
  private static boolean isSpecialIp(String ip) { if (ip.contains(“:”)) return true; if (ip.startsWith(“127.”)) return true; if (ip.startsWith(“169.254.”)) return true; if (ip.equals(“255.255.255.255”)) return true; return false; }

}


2. dubbo中的方式
```java
private static InetAddress getLocalAddress0() {
    InetAddress localAddress = null;
    // 首先尝试获取 /etc/hosts 中 hostname 对应的 IP
    localAddress = InetAddress.getLocalHost();
    Optional<InetAddress> addressOp = toValidAddress(localAddress);
    if (addressOp.isPresent()) {
        return addressOp.get();
    }

    // 没有找到适合注册的 IP，则开始轮询网卡
    Enumeration<NetworkInterface> interfaces = NetworkInterface.getNetworkInterfaces();
    if (null == interfaces) {
        return localAddress;
    }
    while (interfaces.hasMoreElements()) {
        NetworkInterface network = interfaces.nextElement();
        if (network.isLoopback() || network.isVirtual() || !network.isUp()) {
            continue;
        }
        Enumeration<InetAddress> addresses = network.getInetAddresses();
        while (addresses.hasMoreElements()) {
            // 返回第一个匹配的适合注册的 IP
            Optional<InetAddress> addressOp = toValidAddress(addresses.nextElement());
            if (addressOp.isPresent()) {
                return addressOp.get();
            }
        }
    }
    return localAddress;
}

private static Optional<InetAddress> toValidAddress(InetAddress address) {
    if (address instanceof Inet6Address) {
        Inet6Address v6Address = (Inet6Address) address;
        if (isValidV6Address(v6Address)) {
            return Optional.ofNullable(normalizeV6Address(v6Address));
        }
    }
    if (isValidV4Address(address)) {
        return Optional.of(address);
    }
    return Optional.empty();
}

static boolean isValidV6Address(Inet6Address address) {
    boolean preferIpv6 = Boolean.getBoolean("java.net.preferIPv6Addresses");
    if (!preferIpv6) {
        return false;
    }
    try {
        return address.isReachable(100);
    } catch (IOException e) {
        // ignore
    }
    return false;
}

static boolean isValidV4Address(InetAddress address) {
    if (address == null || address.isLoopbackAddress()) {
        return false;
    }
    String name = address.getHostAddress();
    boolean result = (name != null
            && IP_PATTERN.matcher(name).matches()
            && !Constants.ANYHOST_VALUE.equals(name)
            && !Constants.LOCALHOST_VALUE.equals(name));
    return result;
}