关于获取本机真实IP

一般情况下，获取的是本机的一个代理地址：127.0.0.1，而并非本机的真是IP。

public static String getRealIp() throws SocketException {
        String localip = null;// 本地IP，如果没有配置外网IP则返回它
        String netip = null;// 外网IP

        Enumeration<NetworkInterface> netInterfaces =
            NetworkInterface.getNetworkInterfaces();
        InetAddress ip = null;
        boolean finded = false;// 是否找到外网IP
        while (netInterfaces.hasMoreElements() && !finded) {
            NetworkInterface ni = netInterfaces.nextElement();
            Enumeration<InetAddress> address = ni.getInetAddresses();
            while (address.hasMoreElements()) {
                ip = address.nextElement();
                if (!ip.isSiteLocalAddress()
                        && !ip.isLoopbackAddress()
                        && ip.getHostAddress().indexOf(":") == -1) {// 外网IP
                    netip = ip.getHostAddress();
                    finded = true;
                    break;
                } else if (ip.isSiteLocalAddress()
                        && !ip.isLoopbackAddress()
                        && ip.getHostAddress().indexOf(":") == -1) {// 内网IP
                    localip = ip.getHostAddress();
                }
            }
        }

        if (netip != null && !"".equals(netip)) {
            return netip;
        } else {
            return localip;
        }
    }

最常用的是如何获取登陆者IP

public String getIpAddr(HttpServletRequest request) {        String ip = request.getHeader("x-forwarded-for");         if(ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {             　　ip = request.getHeader("Proxy-Client-IP");         }         if(ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {             　　ip = request.getHeader("WL-Proxy-Client-IP");         }         if(ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {            　　ip = request.getRemoteAddr();         }        　　return ip;    } 

/**
     * 获取当前网络ip
     * @param request
     * @return*/
    public String getIpAddr(HttpServletRequest request){
        String ipAddress = request.getHeader("x-forwarded-for");
            if(ipAddress == null || ipAddress.length() == 0 || "unknown".equalsIgnoreCase(ipAddress)) {
                ipAddress = request.getHeader("Proxy-Client-IP");
            }
            if(ipAddress == null || ipAddress.length() == 0 || "unknown".equalsIgnoreCase(ipAddress)) {
                ipAddress = request.getHeader("WL-Proxy-Client-IP");
            }
            if(ipAddress == null || ipAddress.length() == 0 || "unknown".equalsIgnoreCase(ipAddress)) {
                ipAddress = request.getRemoteAddr();
                if(ipAddress.equals("127.0.0.1") || ipAddress.equals("0:0:0:0:0:0:0:1")){
                    //根据网卡取本机配置的IP
                    InetAddress inet=null;
                    try {
                        inet = InetAddress.getLocalHost();
                    } catch (UnknownHostException e) {
                        e.printStackTrace();
                    }
                    ipAddress= inet.getHostAddress();
                }
            }
            //对于通过多个代理的情况，第一个IP为客户端真实IP,多个IP按照‘,‘分割
            if(ipAddress!=null && ipAddress.length()>15){ //"***.***.***.***".length() = 15
                if(ipAddress.indexOf(",")>0){
                    ipAddress = ipAddress.substring(0,ipAddress.indexOf(","));
                }
            }
            return ipAddress;
    }