Add runtime hints for WebFlux

Closes gh-28701

spring-web/src/main/java/org/springframework/http/codec/CodecConfigurerHintsRegistrar.java

@@ -0,0 +1,46 @@
+/*
+ * Copyright 2002-2022 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.http.codec;
+
+import org.springframework.aot.hint.MemberCategory;
+import org.springframework.aot.hint.RuntimeHints;
+import org.springframework.aot.hint.RuntimeHintsRegistrar;
+import org.springframework.aot.hint.TypeReference;
+import org.springframework.http.codec.support.DefaultClientCodecConfigurer;
+import org.springframework.http.codec.support.DefaultServerCodecConfigurer;
+import org.springframework.lang.Nullable;
+
+/**
+ * {@link RuntimeHintsRegistrar} implementation that registers runtime hints for
+ * implementations listed in {@code CodecConfigurer.properties}.
+ *
+ * @author Sebastien Deleuze
+ * @since 6.0
+ */
+public class CodecConfigurerHintsRegistrar implements RuntimeHintsRegistrar {
+
+	@Override
+	public void registerHints(RuntimeHints hints, @Nullable ClassLoader classLoader) {
+		hints.resources().registerPattern("org/springframework/http/codec/CodecConfigurer.properties");
+		hints.reflection().registerType(DefaultClientCodecConfigurer.class, builder ->
+				builder.onReachableType(TypeReference.of(CodecConfigurerFactory.class))
+						.withMembers(MemberCategory.INVOKE_PUBLIC_CONSTRUCTORS));
+		hints.reflection().registerType(DefaultServerCodecConfigurer.class, builder ->
+				builder.onReachableType(TypeReference.of(CodecConfigurerFactory.class))
+						.withMembers(MemberCategory.INVOKE_PUBLIC_CONSTRUCTORS));
+	}
+}