Java获取客户端真实IP地址的代码

public static 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.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();          }          return ip;      }