Tukukkk

In my Java application I use Spring Webflux as dependency like:

<dependencies>

    <dependency>

        <groupId>org.springframework.boot</groupId>

        <artifactId>spring-boot-starter-webflux</artifactId>

        <version>2.1.0.RELEASE</version>

    </dependency>

</dependencies>

With version 2.0.6.RELEASE I could start Netty server with this code:

public static void main(String args) {

    RouterFunction<?> route;

    route = route(GET("/hello"),

            request -> {

                Mono<String> hi = Mono.just("hi");

                return ServerResponse.ok().contentType(TEXT_PLAIN).body(hi, String.class);

            });

    HttpHandler httpHandler = RouterFunctions.toHttpHandler(route);

    ReactorHttpHandlerAdapter adapter =

            new ReactorHttpHandlerAdapter(httpHandler);

    HttpServer server = HttpServer.create("localhost", 8080);

    server.startAndAwait(adapter);

}

but in 2.1.0 it doesn't compile. I also tried something like this, but still can't make it works.

    HttpServer

            .create()

            .host("localhost")

            .port(8080)

            .handle(adapter)

            .bind()

            .block();

How to start the Netty server?

https://docs.spring.io/spring/docs/current/spring-framework-reference/web-reactive.html#webflux-httphandler
https://projectreactor.io/docs/netty/release/api/

You don't need to manually start your server in a Spring Boot application, you can just declare your RouterFunction as @Bean like this:

@Bean

public RouterFunction<ServerResponse> hello() {

    return route(GET("/hello"),

            request -> {

                Mono<String> hi = Mono.just("hi");

                return ServerResponse.ok().contentType(TEXT_PLAIN).body(hi, String.class);

            });

}

Spring Boot is shielding you from the underlying API changes in the supported servers.

The main method here doesn't look like a typical Spring Boot main method, so I don't think you're actually using Spring Boot here. In any case, here's a code snippet that fixes your issue; since Reactor Netty 0.8, the bind() part is separated from the actual waiting part:

RouterFunction<?> route = RouterFunctions.route(RequestPredicates.GET("/hello"),

                request -> {

                    Mono<String> hi = Mono.just("hi");

                    return ServerResponse.ok().contentType(MediaType.TEXT_PLAIN).body(hi, String.class);

                });

HttpHandler httpHandler = RouterFunctions.toHttpHandler(route);

ReactorHttpHandlerAdapter adapter =

        new ReactorHttpHandlerAdapter(httpHandler);

HttpServer server = HttpServer.create().host("localhost").port(8080);

DisposableServer disposableServer = server.handle(adapter).bind().block();

disposableServer.onDispose().block();