@EnableWebFlux setup supports WebSocketHandler

Closes gh-22587

src/docs/asciidoc/web/webflux-websocket.adoc

@@ -54,7 +54,7 @@ The following example shows how to do so:
 	}
 ----
 
-Then you can map it to a URL and add a `WebSocketHandlerAdapter`, as the following example shows:
+Then you can map it to a URL:
 
 [source,java,indent=0,subs="verbatim,quotes",role="primary"]
 .Java
@@ -70,11 +70,6 @@ Then you can map it to a URL and add a `WebSocketHandlerAdapter`, as the followi
 
 			return new SimpleUrlHandlerMapping(map, order);
 		}
-
-		@Bean
-		public WebSocketHandlerAdapter handlerAdapter() {
-			return new WebSocketHandlerAdapter();
-		}
 	}
 ----
 [source,kotlin,indent=0,subs="verbatim,quotes",role="secondary"]
@@ -90,6 +85,34 @@ Then you can map it to a URL and add a `WebSocketHandlerAdapter`, as the followi
 
 			return SimpleUrlHandlerMapping(map, order)
 		}
+	}
+----
+
+If using the <<web-reactive.adoc#webflux-config, WebFlux Config>> there is nothing
+further to do, or otherwise if not using the WebFlux config you'll need to declare a
+`WebSocketHandlerAdapter` as shown below:
+
+[source,java,indent=0,subs="verbatim,quotes",role="primary"]
+.Java
+----
+	@Configuration
+	class WebConfig {
+
+		// ...
+
+		@Bean
+		public WebSocketHandlerAdapter handlerAdapter() {
+			return new WebSocketHandlerAdapter();
+		}
+	}
+----
+[source,kotlin,indent=0,subs="verbatim,quotes",role="secondary"]
+.Kotlin
+----
+	@Configuration
+	class WebConfig {
+
+		// ...
 
 		@Bean
 		fun handlerAdapter() =  WebSocketHandlerAdapter()
@@ -333,9 +356,11 @@ into the attributes of the `WebSocketSession`.
 === Server Configation
 [.small]#<<web.adoc#websocket-server-runtime-configuration, Same as in the Servlet stack>>#
 
-The `RequestUpgradeStrategy` for each server exposes WebSocket-related configuration
-options available for the underlying WebSocket engine. The following example sets
-WebSocket options when running on Tomcat:
+The `RequestUpgradeStrategy` for each server exposes configuration specific to the
+underlying WebSocket server engine. When using the WebFlux Java config you can customize
+such properties as shown in the corresponding section of the
+<<web-reactive.adoc#webflux-config-websocket-service, WebFlux Config>>, or otherwise if
+not using the WebFlux config, use the below:
 
 [source,java,indent=0,subs="verbatim,quotes",role="primary"]
 .Java

src/docs/asciidoc/web/webflux.adoc

@@ -4289,6 +4289,53 @@ reliance on it.
 
 
 
+[[webflux-config-websocket-service]]
+=== WebSocketService
+
+The WebFlux Java config declares of a `WebSocketHandlerAdapter` bean which provides
+support for the invocation of WebSocket handlers. That means all that remains to do in
+order to handle a WebSocket handshake request is to map a `WebSocketHandler` to a URL
+via `SimpleUrlHandlerMapping`.
+
+In some cases it may be necessary to create the `WebSocketHandlerAdapter` bean with a
+provided `WebSocketService` service which allows configuring WebSocket server properties.
+For example:
+
+[source,java,indent=0,subs="verbatim,quotes",role="primary"]
+.Java
+----
+	@Configuration
+	@EnableWebFlux
+	public class WebConfig implements WebFluxConfigurer {
+
+		@Override
+		public WebSocketService getWebSocketService() {
+			TomcatRequestUpgradeStrategy strategy = new TomcatRequestUpgradeStrategy();
+			strategy.setMaxSessionIdleTimeout(0L);
+			return new HandshakeWebSocketService(strategy);
+		}
+	}
+----
+[source,kotlin,indent=0,subs="verbatim,quotes",role="secondary"]
+.Kotlin
+----
+	@Configuration
+	@EnableWebFlux
+	class WebConfig : WebFluxConfigurer {
+
+		@Override
+		fun webSocketService(): WebSocketService {
+			val strategy = TomcatRequestUpgradeStrategy().apply {
+				setMaxSessionIdleTimeout(0L)
+			}
+			return HandshakeWebSocketService(strategy)
+		}
+	}
+----
+
+
+
+
 [[webflux-config-advanced-java]]
 === Advanced Configuration Mode
 [.small]#<<web.adoc#mvc-config-advanced-java, Web MVC>>#