NetworkInterface get the host IP, judge the internal and external network

I. NetworkInterface concept

Java provides a NetworkInterface class. This class can get information about all the physical network interfaces of the machine and the logical network interfaces that the virtual machines and other software use to create the physical network interface of the machine.
Step One: NetworkInterface enumerates all of the network interfaces of the machine by means of the Getnetworkinterfaces method.

Step two: Traverse all network IPs, get native IP

Two. Java implementation

Private Staticstring Getlocalip () {string SIP=NULL; InetAddress IP=NULL; BooleanBfindip =false; Enumeration<NetworkInterface> netinterfaces =NULL; Try{netinterfaces= (enumeration<networkinterface>) networkinterface.getnetworkinterfaces (); } Catch(SocketException e) {e.printstacktrace (); }         while(Netinterfaces.hasmoreelements ()) {if(BFINDIP) { Break; } networkinterface ni=(NetworkInterface) netinterfaces.nextelement (); //----------specific situations, consider using Ni.getname to judge//Traverse all IPsenumeration<inetaddress> ips =ni.getinetaddresses ();  while(Ips.hasmoreelements ()) {IP=(inetaddress) ips.nextelement (); if(Ip.issitelocaladdress () &&!ip.isloopbackaddress ()//127. Start with Lookback address&& ip.gethostaddress (). IndexOf (":") = =-1) {Bfindip=true;  Break; }            }        }        if(IP! =NULL) {SIP=ip.gethostaddress (); }        returnsip; }

Three. js distinguish inside and outside the network

functionGetipnum (ipAddress) {varIP =NewArray (); IP= Ipaddress.split ("."); varA = parseint (ip[0]); varb = parseint (ip[1]); varc = parseint (ip[2]); varD = parseint (ip[3]); returnA * * * * * * * * * * * * * * * + + c * 256 +D; }//is the intranetfunctionIsinnerip (IP) {varA1 = Getipnum ("10.0.0.0"); varA2 = Getipnum ("10.255.255.255"); varB1 = Getipnum ("172.16.0.0"); varB2 = Getipnum ("172.31.255.255"); varC1 = Getipnum ("192.168.0.0"); varC2 = Getipnum ("192.168.255.255"); varD1 = Getipnum ("10.44.0.0"); varD2 = Getipnum ("10.69.0.255"); varn =getipnum (IP); return(n >= A1 && n <= a2) | | (N >= b1 && n <= b2) | | (n >= C1 && n <= c2) | | (n >= d1 && n <=D2);}/** * * * intercept URL Request parameters * * @param paras * @returns*/functionGetrequesturl (paras) {varURL =Location.href; varparastring = url.substring (Url.indexof ("?") + 1, url.length). Split ("&"); varParaobj = {}     for(i = 0; j = parastring[i]; i++) {paraobj[j.substring (0, J.indexof ("=")). toLowerCase ()] =j.substring (J. IndexOf ("=") + 1, j.length); }    varReturnValue =paraobj[paras.tolowercase ()]; if(typeof(returnvalue) = = "Undefined") {        return""; } Else {        returnreturnvalue; }}

　　

NetworkInterface get the host IP, judge the internal and external network