why the url statistic disply null

[auqf]

[auqf]

I use the ai tools analysis the code, and give the following advice:

[ga-ram]

Cases Where URI Statistics Are Aggregated as /NULL

When a trace finishes, the Agent reads the URI template recorded in the trace. If the URI template is still Java null, the Agent replaces it with /NULL before sending the URI statistics.

Trace finishes
  → Read the URI template
  → URI template is null
  → Replace it with "/NULL"
  → Send URI statistics

Common Cases

Case	Description
No route matched	The framework does not provide a matching URI pattern. Typical examples include 404 responses and requests to unmapped URLs.
Request terminated before routing	The request is rejected or fails in a filter, security layer, or servlet container before reaching the framework's handler-mapping stage.
Framework-specific URI statistics are disabled	Global URI statistics are enabled, but settings such as profiler.uri.stat.spring.webmvc.enable or profiler.uri.stat.spring.webflux.enable are disabled.
Unsupported web framework	URI statistics are enabled globally, but the application uses a framework for which Pinpoint does not record URI templates.
Instrumentation failure or version incompatibility	The URI-recording interceptor is not applied because the framework's class or method signature is unsupported or has changed.
Tomcat is used without a higher-level supported framework	The Tomcat plugin does not record the raw request URI as a URI template by default. Without Spring MVC or explicit user input, the URI template can remain null.
User-defined URI template is missing	useuserinput is enabled, but the pinpoint.metric.uri-template request or exchange attribute is missing, empty, or set too late.
Spring MVC matching pattern is unavailable	HandlerMapping.bestMatchingPattern is not present or does not contain a valid URI pattern.
Spring WebFlux matching pattern is unavailable	HandlerMapping.bestMatchingPattern is missing or is not a supported PathPattern value.
Vert.x route information is unavailable	RoutingContext.currentRoute() is null, or the selected route does not provide a non-empty path.
Non-HTTP entry trace	URI Stat storage is attached to root traces generally. A message consumer or another non-HTTP entry point can therefore be collected without any URI template.
A custom plugin records null	A custom integration calls recordUriTemplate(null, true) or otherwise overwrites the URI template with null.

Important Configuration Combination

The following configuration can generate a large amount of /NULL data because global URI statistics remain enabled while WebFlux URI extraction is disabled:

profiler.uri.stat.enable=true
profiler.uri.stat.spring.webflux.enable=false

For user-defined WebFlux URI templates, all relevant settings must be enabled:

profiler.uri.stat.enable=true
profiler.uri.stat.spring.webflux.enable=true
profiler.uri.stat.spring.webflux.useuserinput=true

The application must set the following exchange attribute before Pinpoint attempts to read it:

exchange.getAttributes().put(
    "pinpoint.metric.uri-template",
    "/users/{id}"
);

On your AI Analysis

The current Pinpoint Spring WebFlux plugin only checks the standard matching-pattern attribute and the user-defined pinpoint.metric.uri-template attribute.

Since it is keep saying about Spring Cloud Gateway, I haven't tested with Spring Cloud Gateway with Spring Webflux and haven't considered this environment. URI STAT is not officially supported in this case.

Any PR on improving Pinpoint Spring WebFlux plugin to support any missing case is always welcome.
Meanwhile, If your /NULL is not one of the Common Cases listed above, I'd recommend to use user-defined pinpoint.metric.uri-template attribute to fill in the gap.

[auqf]

I found the proble in the spring gateway is obvious， you can have a test, and i use the ai analysis your answer, it's says as follows:
核心原因：Case 9 — Spring WebFlux matching pattern is unavailable
RoutePredicateHandlerMapping（Gateway 的路由处理器）不设置 HandlerMapping.bestMatchingPattern 到 exchange attribute，它存的是自己的 GATEWAY_ROUTE_ATTR。pinpoint 的 interceptors 只认 bestMatchingPattern，所以永远读不到 → URI = null。
次要原因：Case 4 — Unsupported web framework
Spring Cloud Gateway 本质上是 webflux 之上的另一个框架，pinpoint 没有专门的 spring-cloud-gateway plugin，现有的 spring-webflux plugin 只覆盖了 @RequestMapping / URL mapping 两种标准路由模式，Gateway 的 RoutePredicateHandlerMapping 不在覆盖范围内。
可配置缓解：Case 7 — User-defined URI template missing
你标出的这段配置说明是对的——如果应用 code 能加 GlobalFilter 设置 pinpoint.metric.uri-template 属性，再配合 useuserinput=true，可以不改 agent 代码解决问题：
profiler.uri.stat.enable=true
profiler.uri.stat.spring.webflux.enable=true
profiler.uri.stat.spring.webflux.useuserinput=true
本质上这是 「Gateway 作为 WebFlux 应用的 URI 提取存在代码盲区」，不是配置能绕过的。需要要么改 agent plugin 加 Gateway 支持，要么在 Gateway 应用侧打补丁填 pinpoint.metric.uri-template。

[ga-ram]

Since you are claiming that there is an "obvious problem to fix," I looked further into whether the existing pinpoint.metric.uri-template mechanism can be configured for Spring Cloud Gateway with WebFlux.

I am not planning to implement Agent code that specifically covers only Spring Cloud Gateway for this purpose. The pinpoint.metric.uri-template attribute was introduced to support additional frameworks and environments such as this one.

Any PR adding native Spring Cloud Gateway support would still be welcome. However, such a change would only become available in a future official release, whose schedule has not yet been determined. In the meantime, the existing user-defined URI-template mechanism can be used as shown below.

Example

The attribute must be set during route matching. Setting it in a GlobalFilter may be too late because Pinpoint can read the URI template before the Gateway filter chain executes.

package com.example.gateway;

import java.util.List;
import java.util.function.Predicate;

import org.springframework.cloud.gateway.handler.predicate.AbstractRoutePredicateFactory;
import org.springframework.stereotype.Component;
import org.springframework.util.StringUtils;
import org.springframework.web.server.ServerWebExchange;

import static org.springframework.cloud.gateway.support.ServerWebExchangeUtils
        .GATEWAY_PREDICATE_MATCHED_PATH_ATTR;

@Component
public class PinpointUriTemplateRoutePredicateFactory
        extends AbstractRoutePredicateFactory<
                PinpointUriTemplateRoutePredicateFactory.Config> {

    private static final String PINPOINT_URI_TEMPLATE =
            "pinpoint.metric.uri-template";

    public PinpointUriTemplateRoutePredicateFactory() {
        super(Config.class);
    }

    @Override
    public List<String> shortcutFieldOrder() {
        return List.of("fallbackTemplate");
    }

    @Override
    public Predicate<ServerWebExchange> apply(Config config) {
        return exchange -> {
            String matchedPath =
                    exchange.getAttribute(GATEWAY_PREDICATE_MATCHED_PATH_ATTR);

            String uriTemplate = StringUtils.hasText(matchedPath)
                    ? matchedPath
                    : config.getFallbackTemplate();

            if (StringUtils.hasText(uriTemplate)) {
                exchange.getAttributes().put(
                        PINPOINT_URI_TEMPLATE,
                        uriTemplate
                );
            }

            // This predicate only records the URI template.
            // It does not reject the route.
            return true;
        };
    }

    public static class Config {

        private String fallbackTemplate;

        public String getFallbackTemplate() {
            return fallbackTemplate;
        }

        public void setFallbackTemplate(String fallbackTemplate) {
            this.fallbackTemplate = fallbackTemplate;
        }
    }
}

Add the custom predicate after the Path predicate:

spring:
  cloud:
    gateway:
      routes:
        - id: user-service
          uri: lb://user-service
          predicates:
            - Path=/users/**
            - PinpointUriTemplate=/users/**

        - id: order-service
          uri: lb://order-service
          predicates:
            - Path=/orders/{orderId}/**
            - PinpointUriTemplate=/orders/{orderId}/**

Enable user-provided WebFlux URI templates in the Pinpoint Agent:

profiler.uri.stat.enable=true
profiler.uri.stat.spring.webflux.enable=true
profiler.uri.stat.spring.webflux.useuserinput=true

PinpointUriTemplate must be placed after Path so that Spring Cloud Gateway has already stored the matched path in the exchange before the custom predicate reads it.