下面列出了java.net.UnknownHostException#initCause ( ) 实例代码，或者点击链接到github查看源代码，也可以在右侧发表评论。
@Override
public List<InetAddress> lookup(String hostname) throws UnknownHostException {
if (hostname == null) throw new UnknownHostException("hostname == null");
InetAddress inetAddress = hosts.get(hostname);
if (inetAddress != null) {
return Collections.singletonList(inetAddress);
}
if (Settings.getBuiltInHosts()) {
inetAddress = builtInHosts.get(hostname);
if (inetAddress != null) {
return Collections.singletonList(inetAddress);
}
}
try {
return Arrays.asList(InetAddress.getAllByName(hostname));
} catch (NullPointerException e) {
UnknownHostException unknownHostException =
new UnknownHostException("Broken system behaviour for dns lookup of " + hostname);
unknownHostException.initCause(e);
throw unknownHostException;
}
}
/**
* 获取本服务的IP
* @return ip
* @throws UnknownHostException 异常
*/
public static InetAddress getLocalHostLANAddress() throws UnknownHostException {
try {
// 遍历所有的网络接口
InetAddress candidateAddress = getLocalHost();
if(candidateAddress != null){
return candidateAddress;
}
// 如果没有发现 non-loopback地址.只能用最次选的方案
InetAddress jdkSuppliedAddress = InetAddress.getLocalHost();
if (jdkSuppliedAddress == null) {
throw new UnknownHostException("The JDK InetAddress.getLocalHost() method unexpectedly returned null.");
}
return jdkSuppliedAddress;
} catch (Exception e) {
UnknownHostException unknownHostException = new UnknownHostException(
"Failed to determine LAN address: " + e);
unknownHostException.initCause(e);
throw unknownHostException;
}
}
@Override
public List<InetAddress> lookup(String hostname) throws UnknownHostException {
if (hostname == null) throw new UnknownHostException("hostname == null");
InetAddress inetAddress = hosts.get(hostname);
if (inetAddress != null) {
return Collections.singletonList(inetAddress);
}
if (Settings.getBuiltInHosts()) {
inetAddress = builtInHosts.get(hostname);
if (inetAddress != null) {
return Collections.singletonList(inetAddress);
}
}
try {
return Arrays.asList(InetAddress.getAllByName(hostname));
} catch (NullPointerException e) {
UnknownHostException unknownHostException =
new UnknownHostException("Broken system behaviour for dns lookup of " + hostname);
unknownHostException.initCause(e);
throw unknownHostException;
}
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Debug.v("onCreate here!");
Debug.d(1, 2, 3, 4, 5);
Debug.i("0", "1", "2", "3"); // will just enumerate strings
Debug.w("%s %s %s", null, null, null); // will call String.format
Debug.e(true, null, Integer.MAX_VALUE, Long.MIN_VALUE);
Debug.wtf("No, really, WTF?!");
// lint in action
Debug.i("%d", false);
Debug.i("array: %s", new int[]{1, 2, 3, 4, 5});
// Trace current method calls chain
Debug.trace(100);
final UnknownHostException exception = new UnknownHostException();
exception.initCause(new Throwable());
Debug.e(exception, "Hello this is a message for exception");
Debug.e(exception);
Debug.i("object as json: %s", json(this));
}
private static InetAddress getLocalHostLANAddress() throws UnknownHostException {
try {
InetAddress candidateAddress = null;
// 遍历所有的网络接口
for (Enumeration<NetworkInterface> ifaces = NetworkInterface.getNetworkInterfaces(); ifaces.hasMoreElements();) {
NetworkInterface iface = (NetworkInterface) ifaces.nextElement();
// 在所有的接口下再遍历IP
for (Enumeration<InetAddress> inetAddrs = iface.getInetAddresses(); inetAddrs.hasMoreElements();) {
InetAddress inetAddr = (InetAddress) inetAddrs.nextElement();
if (!inetAddr.isLoopbackAddress()) {// 排除loopback类型地址
if (inetAddr.isSiteLocalAddress()) {
// 如果是site-local地址，就是它了
return inetAddr;
} else if (candidateAddress == null) {
// site-local类型的地址未被发现，先记录候选地址
candidateAddress = inetAddr;
}
}
}
}
if (candidateAddress != null) {
return candidateAddress;
}
// 如果没有发现 non-loopback地址.只能用最次选的方案
InetAddress jdkSuppliedAddress = InetAddress.getLocalHost();
if (jdkSuppliedAddress == null) {
throw new UnknownHostException("The JDK InetAddress.getLocalHost() method unexpectedly returned null.");
}
return jdkSuppliedAddress;
} catch (Exception e) {
UnknownHostException unknownHostException = new UnknownHostException(
"Failed to determine LAN address: " + e);
unknownHostException.initCause(e);
throw unknownHostException;
}
}
/**
* https://stackoverflow.com/questions/9481865/getting-the-ip-address-of-the-current-machine-using-java
*
* <p>
* Returns an <code>InetAddress</code> object encapsulating what is most likely the machine's LAN IP address.
* <p/>
* This method is intended for use as a replacement of JDK method <code>InetAddress.getLocalHost</code>, because
* that method is ambiguous on Linux systems. Linux systems enumerate the loopback network interface the same
* way as regular LAN network interfaces, but the JDK <code>InetAddress.getLocalHost</code> method does not
* specify the algorithm used to select the address returned under such circumstances, and will often return the
* loopback address, which is not valid for network communication. Details
* <a href="http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4665037">here</a>.
* <p/>
* This method will scan all IP addresses on all network interfaces on the host machine to determine the IP address
* most likely to be the machine's LAN address. If the machine has multiple IP addresses, this method will prefer
* a site-local IP address (e.g. 192.168.x.x or 10.10.x.x, usually IPv4) if the machine has one (and will return the
* first site-local address if the machine has more than one), but if the machine does not hold a site-local
* address, this method will return simply the first non-loopback address found (IPv4 or IPv6).
* <p/>
* If this method cannot find a non-loopback address using this selection algorithm, it will fall back to
* calling and returning the result of JDK method <code>InetAddress.getLocalHost</code>.
* <p/>
*
* @throws UnknownHostException If the LAN address of the machine cannot be found.
*/
private static InetAddress getLocalHostLanAddress() throws UnknownHostException {
try {
InetAddress candidateAddress = null;
// Iterate all NICs (network interface cards)...
for (Enumeration ifaces = NetworkInterface.getNetworkInterfaces(); ifaces.hasMoreElements(); ) {
NetworkInterface iface = (NetworkInterface) ifaces.nextElement();
// Iterate all IP addresses assigned to each card...
for (Enumeration inetAddrs = iface.getInetAddresses(); inetAddrs.hasMoreElements(); ) {
InetAddress inetAddr = (InetAddress) inetAddrs.nextElement();
if (!inetAddr.isLoopbackAddress()) {
if (inetAddr.isSiteLocalAddress()) {
// Found non-loopback site-local address. Return it immediately...
return inetAddr;
} else if (candidateAddress == null) {
// Found non-loopback address, but not necessarily site-local.
// Store it as a candidate to be returned if site-local address is not subsequently found...
candidateAddress = inetAddr;
// Note that we don't repeatedly assign non-loopback non-site-local addresses as candidates,
// only the first. For subsequent iterations, candidate will be non-null.
}
}
}
}
if (candidateAddress != null) {
// We did not find a site-local address, but we found some other non-loopback address.
// Server might have a non-site-local address assigned to its NIC (or it might be running
// IPv6 which deprecates the "site-local" concept).
// Return this non-loopback candidate address...
return candidateAddress;
}
// At this point, we did not find a non-loopback address.
// Fall back to returning whatever InetAddress.getLocalHost() returns...
InetAddress jdkSuppliedAddress = InetAddress.getLocalHost();
if (jdkSuppliedAddress == null) {
throw new UnknownHostException("The JDK InetAddress.getLocalHost() method unexpectedly returned null.");
}
return jdkSuppliedAddress;
} catch (Exception e) {
UnknownHostException unknownHostException = new UnknownHostException("Failed to determine LAN address: " + e);
unknownHostException.initCause(e);
throw unknownHostException;
}
}
/**
* https://stackoverflow.com/questions/9481865/getting-the-ip-address-of-the-current-machine-using-java
*
* <p>
* Returns an <code>InetAddress</code> object encapsulating what is most likely the machine's LAN IP address.
* <p/>
* This method is intended for use as a replacement of JDK method <code>InetAddress.getLocalHost</code>, because
* that method is ambiguous on Linux systems. Linux systems enumerate the loopback network interface the same
* way as regular LAN network interfaces, but the JDK <code>InetAddress.getLocalHost</code> method does not
* specify the algorithm used to select the address returned under such circumstances, and will often return the
* loopback address, which is not valid for network communication. Details
* <a href="http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4665037">here</a>.
* <p/>
* This method will scan all IP addresses on all network interfaces on the host machine to determine the IP address
* most likely to be the machine's LAN address. If the machine has multiple IP addresses, this method will prefer
* a site-local IP address (e.g. 192.168.x.x or 10.10.x.x, usually IPv4) if the machine has one (and will return the
* first site-local address if the machine has more than one), but if the machine does not hold a site-local
* address, this method will return simply the first non-loopback address found (IPv4 or IPv6).
* <p/>
* If this method cannot find a non-loopback address using this selection algorithm, it will fall back to
* calling and returning the result of JDK method <code>InetAddress.getLocalHost</code>.
* <p/>
*
* @throws UnknownHostException If the LAN address of the machine cannot be found.
*/
private static InetAddress getLocalHostLANAddress() throws UnknownHostException {
try {
InetAddress candidateAddress = null;
// Iterate all NICs (network interface cards)...
for (Enumeration ifaces = NetworkInterface.getNetworkInterfaces(); ifaces.hasMoreElements(); ) {
NetworkInterface iface = (NetworkInterface) ifaces.nextElement();
// Iterate all IP addresses assigned to each card...
for (Enumeration inetAddrs = iface.getInetAddresses(); inetAddrs.hasMoreElements(); ) {
InetAddress inetAddr = (InetAddress) inetAddrs.nextElement();
if (!inetAddr.isLoopbackAddress()) {
if (inetAddr.isSiteLocalAddress()) {
// Found non-loopback site-local address. Return it immediately...
return inetAddr;
} else if (candidateAddress == null) {
// Found non-loopback address, but not necessarily site-local.
// Store it as a candidate to be returned if site-local address is not subsequently found...
candidateAddress = inetAddr;
// Note that we don't repeatedly assign non-loopback non-site-local addresses as candidates,
// only the first. For subsequent iterations, candidate will be non-null.
}
}
}
}
if (candidateAddress != null) {
// We did not find a site-local address, but we found some other non-loopback address.
// Server might have a non-site-local address assigned to its NIC (or it might be running
// IPv6 which deprecates the "site-local" concept).
// Return this non-loopback candidate address...
return candidateAddress;
}
// At this point, we did not find a non-loopback address.
// Fall back to returning whatever InetAddress.getLocalHost() returns...
InetAddress jdkSuppliedAddress = InetAddress.getLocalHost();
if (jdkSuppliedAddress == null) {
throw new UnknownHostException("The JDK InetAddress.getLocalHost() method unexpectedly returned null.");
}
return jdkSuppliedAddress;
} catch (Exception e) {
UnknownHostException unknownHostException = new UnknownHostException("Failed to determine LAN address: " + e);
unknownHostException.initCause(e);
throw unknownHostException;
}
}
/**
* Returns the {@link EndpointGroup} this client will connect to, derived from {@link #hosts()}.
*
* @throws UnknownHostException if failed to resolve the host names from the DNS servers
*/
protected final EndpointGroup endpointGroup() throws UnknownHostException {
final Set<InetSocketAddress> hosts = hosts();
checkState(!hosts.isEmpty(), "no hosts were added.");
final InetSocketAddress firstHost = Iterables.getFirst(hosts, null);
if (hosts.size() == 1 && !firstHost.isUnresolved()) {
return toResolvedHostEndpoint(firstHost);
}
final List<Endpoint> staticEndpoints = new ArrayList<>();
final List<EndpointGroup> groups = new ArrayList<>();
for (final InetSocketAddress addr : hosts) {
if (addr.isUnresolved()) {
groups.add(DnsAddressEndpointGroup.builder(addr.getHostString())
.eventLoop(clientFactory.eventLoopGroup().next())
.port(addr.getPort())
.build());
} else {
staticEndpoints.add(toResolvedHostEndpoint(addr));
}
}
if (!staticEndpoints.isEmpty()) {
groups.add(EndpointGroup.of(staticEndpoints));
}
final EndpointGroup group;
if (groups.size() == 1) {
group = groups.get(0);
} else {
group = new CompositeEndpointGroup(groups, EndpointSelectionStrategy.roundRobin());
}
if (group instanceof DynamicEndpointGroup) {
// Wait until the initial endpointGroup list is ready.
try {
group.whenReady().get(10, TimeUnit.SECONDS);
} catch (Exception e) {
final UnknownHostException cause = new UnknownHostException(
"failed to resolve any of: " + hosts);
cause.initCause(e);
throw cause;
}
}
if (!healthCheckInterval.isZero()) {
return HealthCheckedEndpointGroup.builder(group, HttpApiV1Constants.HEALTH_CHECK_PATH)
.clientFactory(clientFactory)
.protocol(isUseTls() ? SessionProtocol.HTTPS
: SessionProtocol.HTTP)
.retryInterval(healthCheckInterval)
.build();
} else {
return group;
}
}
private static InetAddress getLocalHostLANAddress() throws UnknownHostException {
try {
InetAddress candidateAddress = null;
// Iterate all NICs (network interface cards)...
for (Enumeration ifaces = NetworkInterface.getNetworkInterfaces(); ifaces.hasMoreElements();) {
NetworkInterface iface = (NetworkInterface) ifaces.nextElement();
// Iterate all IP addresses assigned to each card...
for (Enumeration inetAddrs = iface.getInetAddresses(); inetAddrs.hasMoreElements();) {
InetAddress inetAddr = (InetAddress) inetAddrs.nextElement();
if (!inetAddr.isLoopbackAddress()) {
if (inetAddr.isSiteLocalAddress()) {
// Found non-loopback site-local address. Return it immediately...
return inetAddr;
} else if (candidateAddress == null) {
// Found non-loopback address, but not necessarily site-local.
// Store it as a candidate to be returned if site-local address is not subsequently found...
candidateAddress = inetAddr;
// Note that we don't repeatedly assign non-loopback non-site-local addresses as candidates,
// only the first. For subsequent iterations, candidate will be non-null.
}
}
}
}
if (candidateAddress != null) {
// We did not find a site-local address, but we found some other non-loopback address.
// Server might have a non-site-local address assigned to its NIC (or it might be running
// IPv6 which deprecates the "site-local" concept).
// Return this non-loopback candidate address...
return candidateAddress;
}
// At this point, we did not find a non-loopback address.
// Fall back to returning whatever InetAddress.getLocalHost() returns...
InetAddress jdkSuppliedAddress = InetAddress.getLocalHost();
if (jdkSuppliedAddress == null) {
throw new UnknownHostException("The JDK InetAddress.getLocalHost() method unexpectedly returned null.");
}
return jdkSuppliedAddress;
} catch (Exception e) {
UnknownHostException unknownHostException = new UnknownHostException("Failed to determine LAN address: " + e);
unknownHostException.initCause(e);
throw unknownHostException;
}
}
/**
* http://stackoverflow.com/questions/9481865/getting-the-ip-address-of-the-current-machine-using-java
* <p>
* Returns an <code>InetAddress</code> object encapsulating what is most likely the machine's LAN IP address.
* <p>
* This method is intended for use as a replacement of JDK method <code>InetAddress.getLocalHost</code>, because
* that method is ambiguous on Linux systems. Linux systems enumerate the loopback network interface the same
* way as regular LAN network interfaces, but the JDK <code>InetAddress.getLocalHost</code> method does not
* specify the algorithm used to select the address returned under such circumstances, and will often return the
* loopback address, which is not valid for network communication. Details
* <a href="http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4665037">here</a>.
* <p>
* This method will scan all IP addresses on all network interfaces on the host machine to determine the IP address
* most likely to be the machine's LAN address. If the machine has multiple IP addresses, this method will prefer
* a site-local IP address (e.g. 192.168.x.x or 10.10.x.x, usually IPv4) if the machine has one (and will return the
* first site-local address if the machine has more than one), but if the machine does not hold a site-local
* address, this method will return simply the first non-loopback address found (IPv4 or IPv6).
* <p>
* If this method cannot find a non-loopback address using this selection algorithm, it will fall back to
* calling and returning the result of JDK method <code>InetAddress.getLocalHost</code>.
* <p>
*
* @throws UnknownHostException If the LAN address of the machine cannot be found.
*/
static InetAddress discoverLANAddress() throws UnknownHostException {
InetAddress inetAddress = InetAddress.getLocalHost();
if (!inetAddress.isLoopbackAddress() && inetAddress.isSiteLocalAddress()) {
return inetAddress;
}
try {
InetAddress candidateAddress = null;
// Iterate all NICs (network interface cards)...
for (Enumeration<NetworkInterface> ifaces = NetworkInterface.getNetworkInterfaces(); ifaces.hasMoreElements(); ) {
NetworkInterface iface = ifaces.nextElement();
// Iterate all IP addresses assigned to each card...
for (Enumeration<InetAddress> inetAddrs = iface.getInetAddresses(); inetAddrs.hasMoreElements(); ) {
InetAddress inetAddr = inetAddrs.nextElement();
if (!inetAddr.isLoopbackAddress()) {
if (inetAddr.isSiteLocalAddress()) {
// Found non-loopback site-local address. Return it immediately...
return inetAddr;
} else if (candidateAddress == null) {
// Found non-loopback address, but not necessarily site-local.
// Store it as a candidate to be returned if site-local address is not subsequently found...
candidateAddress = inetAddr;
// Note that we don't repeatedly assign non-loopback non-site-local addresses as candidates,
// only the first. For subsequent iterations, candidate will be non-null.
}
}
}
}
if (candidateAddress != null) {
// We did not find a site-local address, but we found some other non-loopback address.
// Server might have a non-site-local address assigned to its NIC (or it might be running
// IPv6 which deprecates the "site-local" concept).
// Return this non-loopback candidate address...
return candidateAddress;
}
// At this point, we did not find a non-loopback address.
// Fall back to returning whatever InetAddress.getLocalHost() returns...
InetAddress jdkSuppliedAddress = InetAddress.getLocalHost();
if (jdkSuppliedAddress == null) {
throw new UnknownHostException("The JDK InetAddress.getLocalHost() method unexpectedly returned null.");
}
return jdkSuppliedAddress;
} catch (Exception e) {
UnknownHostException unknownHostException = new UnknownHostException("Failed to determine LAN address: " + e);
unknownHostException.initCause(e);
throw unknownHostException;
}
}
/**
* Returns an <code>InetAddress</code> object encapsulating what is most likely the machine's LAN IP address.
* <p/>
* This method is intended for use as a replacement of JDK method <code>InetAddress.getLocalHost</code>, because
* that method is ambiguous on Linux systems. Linux systems enumerate the loopback network interface the same
* way as regular LAN network interfaces, but the JDK <code>InetAddress.getLocalHost</code> method does not
* specify the algorithm used to select the address returned under such circumstances, and will often return the
* loopback address, which is not valid for network communication. Details
* <a href="http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4665037">here</a>.
* <p/>
* This method will scan all IP addresses on all network interfaces on the host machine to determine the IP address
* most likely to be the machine's LAN address. If the machine has multiple IP addresses, this method will prefer
* a site-local IP address (e.g. 192.168.x.x or 10.10.x.x, usually IPv4) if the machine has one (and will return the
* first site-local address if the machine has more than one), but if the machine does not hold a site-local
* address, this method will return simply the first non-loopback address found (IPv4 or IPv6).
* <p/>
* If this method cannot find a non-loopback address using this selection algorithm, it will fall back to
* calling and returning the result of JDK method <code>InetAddress.getLocalHost</code>.
* <p/>
*
* @throws java.net.UnknownHostException If the LAN address of the machine cannot be found.
* @return The LAN address of the machine
*/
public static InetAddress getLocalHostLANAddress() throws UnknownHostException {
try {
InetAddress candidateAddress = null;
// Iterate all NICs (network interface cards)...
for (Enumeration ifaces = NetworkInterface.getNetworkInterfaces(); ifaces.hasMoreElements();) {
NetworkInterface iface = (NetworkInterface) ifaces.nextElement();
// Iterate all IP addresses assigned to each card...
for (Enumeration inetAddrs = iface.getInetAddresses(); inetAddrs.hasMoreElements();) {
InetAddress inetAddr = (InetAddress) inetAddrs.nextElement();
if (!inetAddr.isLoopbackAddress()) {
if (inetAddr.isSiteLocalAddress()) {
// Found non-loopback site-local address. Return it immediately...
return inetAddr;
}
else if (candidateAddress == null) {
// Found non-loopback address, but not necessarily site-local.
// Store it as a candidate to be returned if site-local address is not subsequently found...
candidateAddress = inetAddr;
// Note that we don't repeatedly assign non-loopback non-site-local addresses as candidates,
// only the first. For subsequent iterations, candidate will be non-null.
}
}
}
}
if (candidateAddress != null) {
// We did not find a site-local address, but we found some other non-loopback address.
// Server might have a non-site-local address assigned to its NIC (or it might be running
// IPv6 which deprecates the "site-local" concept).
// Return this non-loopback candidate address...
return candidateAddress;
}
// At this point, we did not find a non-loopback address.
// Fall back to returning whatever InetAddress.getLocalHost() returns...
InetAddress jdkSuppliedAddress = InetAddress.getLocalHost();
if (jdkSuppliedAddress == null) {
throw new UnknownHostException("The JDK InetAddress.getLocalHost() method unexpectedly returned null.");
}
return jdkSuppliedAddress;
}
catch (Exception e) {
UnknownHostException unknownHostException = new UnknownHostException("Failed to determine LAN address: " + e);
unknownHostException.initCause(e);
throw unknownHostException;
}
}
/**
* @hide - internal use only.
*/
public UnknownHostException rethrowAsUnknownHostException(String detailMessage) throws UnknownHostException {
UnknownHostException newException = new UnknownHostException(detailMessage);
newException.initCause(this);
throw newException;
}
/**
* Returns an <code>InetAddress</code> object encapsulating what is most likely the machine's LAN IP address.
* <p/>
* This method is intended for use as a replacement of JDK method <code>InetAddress.getLocalHost</code>, because
* that method is ambiguous on Linux systems. Linux systems enumerate the loopback network interface the same
* way as regular LAN network interfaces, but the JDK <code>InetAddress.getLocalHost</code> method does not
* specify the algorithm used to select the address returned under such circumstances, and will often return the
* loopback address, which is not valid for network communication. Details
* <a href="http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4665037">here</a>.
* <p/>
* This method will scan all IP addresses on all network interfaces on the host machine to determine the IP address
* most likely to be the machine's LAN address. If the machine has multiple IP addresses, this method will prefer
* a site-local IP address (e.g. 192.168.x.x or 10.10.x.x, usually IPv4) if the machine has one (and will return the
* first site-local address if the machine has more than one), but if the machine does not hold a site-local
* address, this method will return simply the first non-loopback address found (IPv4 or IPv6).
* <p/>
* If this method cannot find a non-loopback address using this selection algorithm, it will fall back to
* calling and returning the result of JDK method <code>InetAddress.getLocalHost</code>.
* <p/>
*
* @throws UnknownHostException If the LAN address of the machine cannot be found.
*/
public static InetAddress getLocalHostLANAddress() throws UnknownHostException {
try {
InetAddress candidateAddress = null;
// Iterate all NICs (network interface cards)...
for (Enumeration<NetworkInterface> ifaces = NetworkInterface.getNetworkInterfaces(); ifaces.hasMoreElements();) {
NetworkInterface iface = ifaces.nextElement();
// Iterate all IP addresses assigned to each card...
for (Enumeration<InetAddress> inetAddrs = iface.getInetAddresses(); inetAddrs.hasMoreElements();) {
InetAddress inetAddr = inetAddrs.nextElement();
if (!inetAddr.isLoopbackAddress()) {
if (inetAddr.isSiteLocalAddress()) {
// Found non-loopback site-local address. Return it immediately...
return inetAddr;
}
else if (candidateAddress == null) {
// Found non-loopback address, but not necessarily site-local.
// Store it as a candidate to be returned if site-local address is not subsequently found...
candidateAddress = inetAddr;
// Note that we don't repeatedly assign non-loopback non-site-local addresses as candidates,
// only the first. For subsequent iterations, candidate will be non-null.
}
}
}
}
if (candidateAddress != null) {
// We did not find a site-local address, but we found some other non-loopback address.
// Server might have a non-site-local address assigned to its NIC (or it might be running
// IPv6 which deprecates the "site-local" concept).
// Return this non-loopback candidate address...
return candidateAddress;
}
// At this point, we did not find a non-loopback address.
// Fall back to returning whatever InetAddress.getLocalHost() returns...
InetAddress jdkSuppliedAddress = InetAddress.getLocalHost();
if (jdkSuppliedAddress == null) {
throw new UnknownHostException("The JDK InetAddress.getLocalHost() method unexpectedly returned null.");
}
return jdkSuppliedAddress;
}
catch (Exception e) {
UnknownHostException unknownHostException = new UnknownHostException("Failed to determine LAN address: " + e);
unknownHostException.initCause(e);
throw unknownHostException;
}
}
/**
* Returns an <code>InetAddress</code> object encapsulating what is most likely the machine's
* LAN IP address.
* <p>
* This method is intended for use as a replacement of JDK method
* <code>InetAddress.getLocalHost</code>, because that method is ambiguous on Linux systems.
* Linux systems enumerate the loopback network interface the same way as regular LAN network
* interfaces, but the JDK <code>InetAddress.getLocalHost</code> method does not specify the
* algorithm used to select the address returned under such circumstances, and will often return
* the loopback address, which is not valid for network communication. Details <a
* href="http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4665037">here</a>.
* <p>
* This method will scan all IP addresses on all network interfaces on the host machine to
* determine the IP address most likely to be the machine's LAN address. If the machine has
* multiple IP addresses, this method will prefer a site-local IP address (e.g. 192.168.x.x or
* 10.10.x.x, usually IPv4) if the machine has one (and will return the first site-local address
* if the machine has more than one), but if the machine does not hold a site-local address,
* this method will return simply the first non-loopback address found (IPv4 or IPv6).</p>
* <p>
* If this method cannot find a non-loopback address using this selection algorithm, it will
* fall back to calling and returning the result of JDK method
* <code>InetAddress.getLocalHost</code>.
* <p>
* <a href="http://issues.apache.org/jira/browse/JCS-40">JIR ISSUE JCS-40</a>
* <p>
* @return InetAddress
* @throws UnknownHostException If the LAN address of the machine cannot be found.
*/
public static InetAddress getLocalHostLANAddress()
throws UnknownHostException
{
try
{
InetAddress candidateAddress = null;
// Iterate all NICs (network interface cards)...
for ( Enumeration<NetworkInterface> ifaces = NetworkInterface.getNetworkInterfaces(); ifaces.hasMoreElements(); )
{
NetworkInterface iface = ifaces.nextElement();
// Iterate all IP addresses assigned to each card...
for ( Enumeration<InetAddress> inetAddrs = iface.getInetAddresses(); inetAddrs.hasMoreElements(); )
{
InetAddress inetAddr = inetAddrs.nextElement();
if ( !inetAddr.isLoopbackAddress() )
{
if ( inetAddr.isSiteLocalAddress() )
{
// Found non-loopback site-local address. Return it immediately...
return inetAddr;
}
else if ( candidateAddress == null )
{
// Found non-loopback address, but not necessarily site-local.
// Store it as a candidate to be returned if site-local address is not subsequently found...
candidateAddress = inetAddr;
// Note that we don't repeatedly assign non-loopback non-site-local addresses as candidates,
// only the first. For subsequent iterations, candidate will be non-null.
}
}
}
}
if ( candidateAddress != null )
{
// We did not find a site-local address, but we found some other non-loopback address.
// Server might have a non-site-local address assigned to its NIC (or it might be running
// IPv6 which deprecates the "site-local" concept).
// Return this non-loopback candidate address...
return candidateAddress;
}
// At this point, we did not find a non-loopback address.
// Fall back to returning whatever InetAddress.getLocalHost() returns...
InetAddress jdkSuppliedAddress = InetAddress.getLocalHost();
if ( jdkSuppliedAddress == null )
{
throw new UnknownHostException( "The JDK InetAddress.getLocalHost() method unexpectedly returned null." );
}
return jdkSuppliedAddress;
}
catch ( SocketException e )
{
UnknownHostException unknownHostException = new UnknownHostException( "Failed to determine LAN address: "
+ e );
unknownHostException.initCause( e );
throw unknownHostException;
}
}