java - 在spring-webflux中处理错误的正确方法是什么

Question

我一直在使用spring-webflux进行一些研究，我想了解使用路由器功能处理错误的正确方法。

我创建了一个小项目来测试几个场景，并且我希望获得有关它的反馈，并查看其他人在做什么。

到目前为止，我在做什么。

提供以下路由功能:

@Component
public class HelloRouter {
    @Bean
    RouterFunction<?> helloRouterFunction() {
        HelloHandler handler = new HelloHandler();
        ErrorHandler error = new ErrorHandler();

        return nest(path("/hello"),
                nest(accept(APPLICATION_JSON),
                        route(GET("/"), handler::defaultHello)
                                .andRoute(POST("/"), handler::postHello)
                                .andRoute(GET("/{name}"), handler::getHello)
                )).andOther(route(RequestPredicates.all(), error::notFound));
    }
}

我已经在我的处理程序上执行了

class HelloHandler {

    private ErrorHandler error;

    private static final String DEFAULT_VALUE = "world";

    HelloHandler() {
        error = new ErrorHandler();
    }

    private Mono<ServerResponse> getResponse(String value) {
        if (value.equals("")) {
            return Mono.error(new InvalidParametersException("bad parameters"));
        }
        return ServerResponse.ok().body(Mono.just(new HelloResponse(value)), HelloResponse.class);
    }

    Mono<ServerResponse> defaultHello(ServerRequest request) {
        return getResponse(DEFAULT_VALUE);
    }

    Mono<ServerResponse> getHello(ServerRequest request) {
        return getResponse(request.pathVariable("name"));
    }

    Mono<ServerResponse> postHello(ServerRequest request) {
        return request.bodyToMono(HelloRequest.class).flatMap(helloRequest -> getResponse(helloRequest.getName()))
                .onErrorResume(error::badRequest);
    }
}

它们是我的错误处理程序:

class ErrorHandler {

    private static Logger logger = LoggerFactory.getLogger(ErrorHandler.class);

    private static BiFunction<HttpStatus,String,Mono<ServerResponse>> response =
    (status,value)-> ServerResponse.status(status).body(Mono.just(new ErrorResponse(value)),
            ErrorResponse.class);

    Mono<ServerResponse> notFound(ServerRequest request){
        return response.apply(HttpStatus.NOT_FOUND, "not found");
    }

    Mono<ServerResponse> badRequest(Throwable error){
        logger.error("error raised", error);
        return response.apply(HttpStatus.BAD_REQUEST, error.getMessage());
    }
}

这是完整的示例存储库:

https://github.com/LearningByExample/reactive-ms-example

Answer 1

Spring 5提供了一个WebHandler，在JavaDoc中有以下一行:

Use HttpWebHandlerAdapter to adapt a WebHandler to an HttpHandler. The WebHttpHandlerBuilder provides a convenient way to do that while also optionally configuring one or more filters and/or exception handlers.

当前，官方文档建议我们在启动任何服务器之前将路由器功能包装到HttpHandler中:

HttpHandler httpHandler = RouterFunctions.toHttpHandler(routerFunction);

借助 WebHttpHandlerBuilder，我们可以配置自定义异常处理程序:

HttpHandler httpHandler = WebHttpHandlerBuilder.webHandler(toHttpHandler(routerFunction))
  .prependExceptionHandler((serverWebExchange, exception) -> {

      /* custom handling goes here */
      return null;

  }).build();