如何使用Spring WebFlux返回404

我有一个像这样的控制器(在Kotlin)：

@RestController
@RequestMapping("/")
class CustomerController (private val service: CustomerService) {
    @GetMapping("/{id}")
    fun findById(@PathVariable id: String,
                 @RequestHeader(value = IF_NONE_MATCH) versionHeader: String?): Mono<HttpEntity<KundeResource>> =
        return service.findById(id)
            .switchIfEmpty(Mono.error(NotFoundException()))
            .map {
                // ETag stuff ...
                ok().eTag("...").body(...)
            }
}

我想知道是否有一个更好的方法而不是抛出一个用@ResponseStatus注释的异常(代码= NOT_FOUND)

解决方法:

当Spring 5稳定时,我想使用RouteFunction而不是@RestController.定义HandlerFunction来处理请求,然后声明一个RouteFunction以将请求映射到HandlerFunction：

public Mono<ServerResponse> get(ServerRequest req) {
    return this.posts
        .findById(req.pathVariable("id"))
        .flatMap((post) -> ServerResponse.ok().body(Mono.just(post), Post.class))
        .switchIfEmpty(ServerResponse.notFound().build());
}

检查完整的示例代码here.

Kotlin版本,定义一个处理请求的函数,使用RouteFunctionDSL将传入的请求映射到HandlerFuncation：

fun get(req: ServerRequest): Mono<ServerResponse> {
    return this.posts.findById(req.pathVariable("id"))
            .flatMap { post -> ok().body(Mono.just(post), Post::class.java) }
            .switchIfEmpty(notFound().build())
}

它可以是一个表达式,如：

fun get(req: ServerRequest): Mono<ServerResponse> = this.posts.findById(req.pathVariable("id"))
            .flatMap { post -> ok().body(Mono.just(post), Post::class.java) }
            .switchIfEmpty(notFound().build())

查看Kotlin DSL here的完整示例代码.

如果您更喜欢传统控制器来公开REST API,请尝试这种方法.

首先定义一个例外,例如. PostNotFoundException.然后把它扔进控制器.

 @GetMapping(value =“/ {id}”)
    public Mono< Post> get(@PathVariable(value =“id”)Long id){
        return this.posts.findById(id).switchIfEmpty(Mono.error(new PostNotFoundException(id)));
    }

定义ExceptionHandler来处理异常,并在HttpHandler中注册它.

@Profile("default")
@Bean
public NettyContext nettyContext(ApplicationContext context) {
    HttpHandler handler = WebHttpHandlerBuilder.applicationContext(context)
        .exceptionHandler(exceptionHandler())
        .build();
    ReactorHttpHandlerAdapter adapter = new ReactorHttpHandlerAdapter(handler);
    HttpServer httpServer = HttpServer.create("localhost", this.port);
    return httpServer.newHandler(adapter).block();
}

@Bean
public WebExceptionHandler exceptionHandler() {
    return (ServerWebExchange exchange, Throwable ex) -> {
        if (ex instanceof PostNotFoundException) {
            exchange.getResponse().setStatusCode(HttpStatus.NOT_FOUND);
            return exchange.getResponse().setComplete();
        }
        return Mono.error(ex);
    };
}

在这里查看complete codes.对于Spring Boot用户,请查看this sample.

标签：spring,spring-boot-2,project-reactor,spring-webflux
来源： https://codeday.me/bug/20190715/1465004.html