Fix MyErrorWebExceptionHandler in documentation

Closes gh-38104

Author: mhalbritter

Diff for: spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/web/reactive/webflux/errorhandling/MyErrorWebExceptionHandler.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2021 the original author or authors.
+ * Copyright 2012-2023 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,12 +18,13 @@
 
 import reactor.core.publisher.Mono;
 
-import org.springframework.boot.autoconfigure.web.WebProperties.Resources;
+import org.springframework.boot.autoconfigure.web.WebProperties;
 import org.springframework.boot.autoconfigure.web.reactive.error.AbstractErrorWebExceptionHandler;
 import org.springframework.boot.web.reactive.error.ErrorAttributes;
 import org.springframework.context.ApplicationContext;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.MediaType;
+import org.springframework.http.codec.ServerCodecConfigurer;
 import org.springframework.stereotype.Component;
 import org.springframework.web.reactive.function.server.RouterFunction;
 import org.springframework.web.reactive.function.server.RouterFunctions;
@@ -34,9 +35,11 @@
 @Component
 public class MyErrorWebExceptionHandler extends AbstractErrorWebExceptionHandler {
 
-	public MyErrorWebExceptionHandler(ErrorAttributes errorAttributes, Resources resources,
-			ApplicationContext applicationContext) {
-		super(errorAttributes, resources, applicationContext);
+	public MyErrorWebExceptionHandler(ErrorAttributes errorAttributes, WebProperties webProperties,
+			ApplicationContext applicationContext, ServerCodecConfigurer serverCodecConfigurer) {
+		super(errorAttributes, webProperties.getResources(), applicationContext);
+		setMessageReaders(serverCodecConfigurer.getReaders());
+		setMessageWriters(serverCodecConfigurer.getWriters());
 	}
 
 	@Override

Diff for: spring-boot-project/spring-boot-docs/src/main/kotlin/org/springframework/boot/docs/web/reactive/webflux/errorhandling/MyErrorWebExceptionHandler.kt

@@ -22,6 +22,7 @@ import org.springframework.boot.web.reactive.error.ErrorAttributes
 import org.springframework.context.ApplicationContext
 import org.springframework.http.HttpStatus
 import org.springframework.http.MediaType
+import org.springframework.http.codec.ServerCodecConfigurer
 import org.springframework.stereotype.Component
 import org.springframework.web.reactive.function.server.RouterFunction
 import org.springframework.web.reactive.function.server.RouterFunctions
@@ -31,8 +32,15 @@ import reactor.core.publisher.Mono
 
 @Suppress("UNUSED_PARAMETER")
 @Component
-class MyErrorWebExceptionHandler(errorAttributes: ErrorAttributes?, resources: WebProperties.Resources?,
-	applicationContext: ApplicationContext?) : AbstractErrorWebExceptionHandler(errorAttributes, resources, applicationContext) {
+class MyErrorWebExceptionHandler(
+		errorAttributes: ErrorAttributes, webProperties: WebProperties,
+		applicationContext: ApplicationContext, serverCodecConfigurer: ServerCodecConfigurer
+) : AbstractErrorWebExceptionHandler(errorAttributes, webProperties.resources, applicationContext) {
+
+	init {
+		setMessageReaders(serverCodecConfigurer.readers)
+		setMessageWriters(serverCodecConfigurer.writers)
+	}
 
 	override fun getRoutingFunction(errorAttributes: ErrorAttributes): RouterFunction<ServerResponse> {
 		return RouterFunctions.route(this::acceptsXml, this::handleErrorAsXml)
@@ -42,7 +50,7 @@ class MyErrorWebExceptionHandler(errorAttributes: ErrorAttributes?, resources: W
 		return request.headers().accept().contains(MediaType.APPLICATION_XML)
 	}
 
-	fun handleErrorAsXml(request: ServerRequest?): Mono<ServerResponse> {
+	fun handleErrorAsXml(request: ServerRequest): Mono<ServerResponse> {
 		val builder = ServerResponse.status(HttpStatus.INTERNAL_SERVER_ERROR)
 		// ... additional builder calls
 		return builder.build()