取得IP地址

	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.getRemoteAddr();
		return ip;
	}