从HTTP请求中获取客户IP地址

/**
     * 从HTTP请求中获取客户IP地址
     *
     * @param request http请求
     * @return 客户IP地址
     */
    public static String getIPAddress( 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;
    }