Get real ip from request

requestIp.java

public static String getClientIP(HttpServletRequest request)
{
    String ip = request.getHeader("X-Real-IP");
    if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip))
        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;
}