获取客户端IP地址

/**
     * 获取客户端Ip地址
     * @param request   HttpServletRequest
     * @return  ip addr
     */
    private String getRemoteIP(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();
        }
        if (ip.contains(",")) {
            List<String> moreIps = Arrays.stream(ip.split(",")).map(String::trim).collect(Collectors.toList());
            String firstReliableIp = moreIps.stream().filter(i -> !"unknown".equalsIgnoreCase(i)).findFirst().orElse(null);
            if (firstReliableIp != null) {
                ip = firstReliableIp;
            }
        }
        return  ip;
    }