Spring函数式端点返回404问题排查求助

问题场景 #

开发同时包含常规端点和函数式端点的Spring应用，常规端点可正常返回结果，但所有函数式端点均返回404。已按照Handler+Router模式实现，相关代码及日志如下：

Handler代码 #

@Service
public class LorcCardHandler {
    private final LorcCardReactiveRepository lorcCardReactiveRepository;

    @Autowired
    public LorcCardHandler(LorcCardReactiveRepository lorcCardReactiveRepository) {
        this.lorcCardReactiveRepository = lorcCardReactiveRepository;
    }

    public Mono<ServerResponse> getCardProjectionList(ServerRequest request) {
        return ServerResponse.ok().body(lorcCardReactiveRepository.getAllCardsProjection(), CardProjection.class);
    }
}

Router代码 #

@Configuration
public class LorcRouter {
    private final LorcCardHandler handler;

    public LorcRouter(LorcCardHandler handler) {
        this.handler = handler;
    }

    @Bean
    public RouterFunction<ServerResponse> getCardListByRoute() {
       return route().path("/lorc", builder -> builder.GET(handler::getCardProjectionList)).build();
    }
}

关键日志信息 #

Bean初始化日志

o.s.b.f.s.DefaultListableBeanFactory : Autowiring by type from beaame 'reactiveMongoTemplate' via factory method to beaamed 'mappingMongoConverter'
o.s.d.r.c.s.RepositoryFactorySuppo: Initializing repository instance for com.luizgomendes.lorc.rest.repository.LorcCardReactiveRepository…
o.s.d.r.c.s.RepositoryFactorySuppo: Finished creation of repository instance for com.luizgomendes.lorc.rest.repository.LorcCardReactiveRepository.
o.s.b.f.s.DefaultListableBeanFactory : Autowiring by type from beaame 'lorcReactiveService' via constructor to beaamed 'lorcCardReactiveRepository'
o.s.b.f.s.DefaultListableBeanFactory : Autowiring by type from beaame 'lorcReactiveController' via constructor to beaamed 'lorcReactiveService'
o.s.b.f.s.DefaultListableBeanFactory : Creating shared instance of singleton bean 'lorcRouter'
o.s.b.f.s.DefaultListableBeanFactory : Creating shared instance of singleton bean 'lorcCardHandler'
o.s.b.f.s.DefaultListableBeanFactory : Autowiring by type from beaame 'lorcCardHandler' via constructor to beaamed 'lorcCardReactiveRepository'
o.s.b.f.s.DefaultListableBeanFactory : Autowiring by type from beaame 'lorcRouter' via constructor to beaamed 'lorcCardHandler'
o.s.b.f.s.DefaultListableBeanFactory : Creating shared instance of singleton bean 'globalExceptionHandler'
o.s.b.f.s.DefaultListableBeanFactory : Creating shared instance of singleton bean 'getCardListByRoute'

服务调用日志

[Lorcana Rest Services] [nio-8080-exec-1] o.s.web.servlet.DispatcherServle : GET "/lorc", parameters={}
[Lorcana Rest Services] [nio-8080-exec-1] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped to ResourceHttpRequestHandler [classpath [META-INF/resources/], classpath [resources/], classpath [static/], classpath [public/], ServletContext [/]]
[Lorcana Rest Services] [nio-8080-exec-1] o.s.w.s.r.ResourceHttpRequestHandl: Resourcot found
[Lorcana Rest Services] [nio-8080-exec-1] .w.s.m.s.DefaultHandlerExceptionResolver : Resolved [org.springframework.web.servlet.resource.NoResourceFoundException: No static resource lorc.]
[Lorcana Rest Services] [nio-8080-exec-1] o.s.web.servlet.DispatcherServle : Completed 404 NOT_FOUND

问题分析 #

从服务调用日志可见，请求被映射到静态资源处理器，而非函数式路由。核心原因：

• 日志中出现o.s.web.servlet.DispatcherServle（Servlet栈的DispatcherServlet），而非WebFlux的org.springframework.web.reactive.DispatcherHandler，说明当前应用运行在Servlet栈环境中，WebFlux的RouterFunction不会被Servlet容器处理。
• 通常是因为项目同时引入了spring-boot-starter-web（Spring MVC）和spring-boot-starter-webflux依赖，Spring Boot默认优先启用Servlet栈，导致WebFlux路由失效。

解决方案 #

1. 清理依赖
   检查项目的pom.xml（Maven）或build.gradle（Gradle），移除spring-boot-starter-web依赖，仅保留spring-boot-starter-webflux。

   Maven示例：

   <!-- 移除该依赖 -->
   <!-- <dependency>
       <groupId>org.springframework.boot</groupId>
       <artifactId>spring-boot-starter-web</artifactId>
   </dependency> -->
   
   <!-- 保留WebFlux依赖 -->
   <dependency>
       <groupId>org.springframework.boot</groupId>
       <artifactId>spring-boot-starter-webflux</artifactId>
   </dependency>
   

2. 验证RouterFunction定义
   确保路由路径配置正确，可调整Router代码写法，显式指定路径匹配规则：

   @Bean
   public RouterFunction<ServerResponse> getCardListByRoute() {
       // 直接匹配GET /lorc
       return route(GET("/lorc"), handler::getCardProjectionList);
   }
   

   或使用path分组的写法（需明确子路径）：

   @Bean
   public RouterFunction<ServerResponse> getCardListByRoute() {
       return route().path("/lorc", builder -> 
           builder.GET("", handler::getCardProjectionList) // 子路径为空，对应/lorc
       ).build();
   }
   

3. 重启应用验证
   调整依赖和代码后，重启应用，再次请求/lorc，检查日志是否出现DispatcherHandler相关的路由匹配日志，确认请求是否正确映射到函数式端点。

内容的提问来源于stack exchange，提问作者Luiz Gustavo Mendes