获取请求主机IP地址,如果通过代理进来，则透过防火墙获取真实IP地址

/**
     * 获取请求主机IP地址,如果通过代理进来，则透过防火墙获取真实IP地址; 
     * @Title: getIpAddress
     * @Description: TODO(这里用一句话描述这个方法的作用)
     * @param @param request
     * @param @return
     * @param @throws IOException    参数
     * @return String    返回类型
     * @throws
     */
    public String getIpAddress(HttpServletRequest request) throws IOException {  
        // 获取请求主机IP地址,如果通过代理进来，则透过防火墙获取真实IP地址  
  
        String ip = request.getHeader("X-Forwarded-For");  
  
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {  
            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.getHeader("HTTP_CLIENT_IP");  
            }  
            if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {  
                ip = request.getHeader("HTTP_X_FORWARDED_FOR");  
            }  
            if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {  
                ip = request.getRemoteAddr();  
            }  
        } else if (ip.length() > 15) {  
            String[] ips = ip.split(",");  
            for (int index = 0; index < ips.length; index++) {  
                String strIp = (String) ips[index];  
                if (!("unknown".equalsIgnoreCase(strIp))) {  
                    ip = strIp;  
                    break;  
                }  
            }  
        }  
        return ip;  
    }