如何通过zuul添加或修改请求参数

RequestContext ctx = RequestContext.getCurrentContext();
httpservletRequest request = ctx.getRequest();

ctx.setRequest(new HttpServletRequestWrapper(request) {})

// 例如在请求参数中添加 userId
try {
  InputStream in = ctx.getRequest().getInputStream();
  String body = StreamUtils.copyToString(in, Charset.forName("UTF-8"));
  if（StringUtils.isBlank(body)）{
    body = "{}";
  }
  JSONObject jsonObject = JSON.parseObject(body);
  jsonObject.put("userId", 666);
  String newBody = jsonObject.toString();
  final byte[] reqBodyBytes = newBody.getBytes();
  ctx.setRequest(new HttpServletRequestWrapper(request){    
    @Override
    public ServletInputStream getInputStream() throws ioException {
      return new ServletInputStreamWrapper(reqBodyBytes);
    }
    @Override
    public int getContentLength() {
      return reqBodyBytes.length;
    }
    @Override
    public long getContentLengthLong() {
      return reqBodyBytes.length;
    }
  });
} catch (IOException e) {
  e.printStackTrace();
}

InputStream in = request().getInputStream();
String body = StreamUtils.copyToString(in, Charset.forName("UTF-8"));
if（StringUtils.isNotBlank(body)）{
  JSONObject jsonObject = JSON.parseObject(body);
  Object userId = jsonObject.get("userId");
}

demo:
  ribbon:
    NIWSServerListClassName: com.netflix.loadbalancer.ConfigurationBasedServerList
    listOfServers: 192.168.99.100,192.168.99.101
zuul:
  routes:
    demo:
      path: /demo/**
      stripPrefix: true
      serviceId: demo

@Component
public class UrlPathFilter extends ZuulFilter{
    @Override
    public String filterType() {
        return FilterConstants.PRE_TYPE;
    }
    @Override
    public int filterOrder() {
        return FilterConstants.PRE_DECORATION_FILTER_ORDER + 1;
    }
    @Override
    public boolean shouldFilter() {
        final String serviceId = (String) RequestContext.getCurrentContext().get("proxy");
        return "demo".equals(serviceId);
    }
    @Override
    public Object run() {
        RequestContext context = RequestContext.getCurrentContext();
        Object originalRequestPath = context.get(FilterConstants.REQUEST_URI_KEY);
        //http://localhost:10000/demo/list/data
        //-->/api/prefix/list/data
        String modifiedRequestPath = "/api/prefix" + originalRequestPath;
        context.put(FilterConstants.REQUEST_URI_KEY, modifiedRequestPath);
        return null;
    }
}