如何獲得客戶端的真實IP

         //獲取客戶端IP
         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.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();
             ip = ip.equals("0:0:0:0:0:0:0:1")?"127.0.0.1":ip;//當你使用localhost訪問的時候ip=0:0:0:0:0:0:0:1
         }
         // 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();
         }