request獲取客戶端IP地址

 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();
  }
  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");
  }
  // 如果是多級代理，那麼取第一個ip爲客戶ip
  if (ip != null && ip.indexOf(",") != -1) {
   ip = ip.substring(ip.lastIndexOf(",") + 1, ip.length()).trim();
  }
  return ip;
 }