Update exchangeToMono Javadoc

This time showing a more representative example.

See gh-27645

Author: rstoyanchev

spring-webflux/src/main/java/org/springframework/web/reactive/function/client/WebClient.java

@@ -519,18 +519,15 @@ interface RequestHeadersSpec<S extends RequestHeadersSpec<S>> {
 		 * scenarios, for example to decode the response differently depending
 		 * on the response status:
 		 * <p><pre>
-		 * Mono&lt;Object&gt; entityMono = client.get()
+		 * Mono&lt;Person&gt; entityMono = client.get()
 		 *     .uri("/persons/1")
 		 *     .accept(MediaType.APPLICATION_JSON)
 		 *     .exchangeToMono(response -&gt; {
 		 *         if (response.statusCode().equals(HttpStatus.OK)) {
 		 *             return response.bodyToMono(Person.class);
 		 *         }
-		 *         else if (response.statusCode().is4xxClientError()) {
-		 *             return response.bodyToMono(ErrorContainer.class);
-		 *         }
 		 *         else {
-		 *             return response.createException();
+		 *             return response.createException().flatMap(Mono::error);
 		 *         }
 		 *     });
 		 * </pre>
@@ -551,18 +548,15 @@ interface RequestHeadersSpec<S extends RequestHeadersSpec<S>> {
 		 * scenarios, for example to decode the response differently depending
 		 * on the response status:
 		 * <p><pre>
-		 * Mono&lt;Object&gt; entityMono = client.get()
+		 * Flux&lt;Person&gt; entityMono = client.get()
 		 *     .uri("/persons")
 		 *     .accept(MediaType.APPLICATION_JSON)
 		 *     .exchangeToFlux(response -&gt; {
 		 *         if (response.statusCode().equals(HttpStatus.OK)) {
 		 *             return response.bodyToFlux(Person.class);
 		 *         }
-		 *         else if (response.statusCode().is4xxClientError()) {
-		 *             return response.bodyToMono(ErrorContainer.class).flux();
-		 *         }
 		 *         else {
-		 *             return response.createException().flux();
+		 *             return response.createException().flatMapMany(Mono::error);
 		 *         }
 		 *     });
 		 * </pre>

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

@@ -546,20 +546,16 @@ depending on the response status:
 [source,java,indent=0,subs="verbatim,quotes",role="primary"]
 .Java
 ----
-	Mono<Object> entityMono = client.get()
+	Mono<Person> entityMono = client.get()
 			.uri("/persons/1")
 			.accept(MediaType.APPLICATION_JSON)
 			.exchangeToMono(response -> {
 				if (response.statusCode().equals(HttpStatus.OK)) {
 					return response.bodyToMono(Person.class);
 				}
-				else if (response.statusCode().is4xxClientError()) {
-					// Suppress error status code
-					return response.bodyToMono(ErrorContainer.class);
-				}
 				else {
 					// Turn to error
-					return response.createException();
+					return response.createException().flatMap(Mono::error);
 				}
 			});
 ----
@@ -573,9 +569,6 @@ val entity = client.get()
 		if (response.statusCode() == HttpStatus.OK) {
 			 return response.awaitBody<Person>()
 		}
-		else if (response.statusCode().is4xxClientError) {
-			 return response.awaitBody<ErrorContainer>()
-		}
 		else {
 			 throw response.createExceptionAndAwait()
 		}