Spring cloud 用zuul做网关，请求头信息丢失

@Component
public class WebFilter extends ZuulFilter {
    @Override
    public String filterType() {
        return "pre";
    }

    @Override
    public int filterOrder() {
        return 0;
    }

    @Override
    public boolean shouldFilter() {
        return true;
    }

    @Override
    public Object run() throws ZuulException {
        System.out.println("zuul过滤器...");
        //向header中添加鉴权令牌
        RequestContext requestContext = RequestContext.getCurrentContext();
        //获取header
        HttpServletRequest request = requestContext.getRequest();
        String authorization = request.getHeader("Authorization");
        if(authorization != null) {
            System.out.println("authorization: " + authorization);
            requestContext.addZuulRequestHeader("Authorization", authorization);
        }
        return null;
    }
}