从request获取远程IP

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;
	  }