Spring Cloud手动创建Feign客户端后zipkin调用链断层问题解决

Spring Cloud下通过手动创建Feign客户端进行服务间调用，导致zipkin调用链被截断，traceId不能延续导致调用链断层

解决方案：为Feign.Builder添加请求拦截器，加入请求头X-B3-TraceId和X-B3-SpanId，值为traceIdString和spanIdString

ChannelGatewayPayApi channelGatewayPayApi;
if ((channelGatewayPayApi = channelGatewayApiMap.get(channelInfo.getChnlCode())) == null) {
    channelGatewayPayApi = feignConfig.getFeignBuilder()
            .requestInterceptor(p -> {
                p.header("X-B3-TraceId", TraceHelper.getTraceIdString());
                p.header("X-B3-SpanId", TraceHelper.getSpanIdString());
                p.header("X-B3-Sampled", String.valueOf(TraceHelper.getSampled()));
                log.info("ChannelPayService.cancel TraceId: {}, SpanId: {}", TraceHelper.getTraceIdString(), TraceHelper.getSpanIdString());
            }).target(ChannelGatewayPayApi.class, "http://" + channelProduct.getServiceAppName());
    channelGatewayApiMap.put(channelInfo.getChnlCode(), channelGatewayPayApi);
    channelGatewayMap.put(channelInfo.getChnlCode(), channelProduct.getServiceAppName().substring(channelProduct.getServiceAppName().indexOf("gateway") + 8));
}