public static String getMultistageReverseProxyIp(String ip) {
		// 多级反向代理检测
		if (ip != null && StrUtil.indexOf(ip, ',') > 0) {
			final List<String> ips = StrUtil.splitTrim(ip, ',');
			for (final String subIp : ips) {
				if (false == isUnknown(subIp)) {
					ip = subIp;
					break;
				}
			}
		}
		return ip;
	}
@Test
	public void issueI64P9JTest() {
		// 获取结果应该去掉空格
		final String ips = "unknown, 12.34.56.78, 23.45.67.89";
		final String ip = NetUtil.getMultistageReverseProxyIp(ips);
		assertEquals("12.34.56.78", ip);
	}