Add support for serialization in RequestMappingReflectiveProcessor

Support reflection-based serialization of parameters annotated
with @RequestBody and return values annotated with @ResponseBody.

It leverages a new BindingReflectionHintsRegistrar class that
is designed to register transitively the types usually needed
for binding and reflection-based serialization on fields,
constructors and properties. Generics are taken in account
as well.

Closes gh-28518

spring-web/src/test/java/org/springframework/web/bind/annotation/RequestMappingReflectiveProcessorTests.java

@@ -0,0 +1,176 @@
+/*
+ * 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.web.bind.annotation;
+
+import java.lang.reflect.Method;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.aot.hint.MemberCategory;
+import org.springframework.aot.hint.ReflectionHints;
+import org.springframework.aot.hint.TypeReference;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link RequestMappingReflectiveProcessor}.
+ *
+ * @author Sebastien Deleuze
+ */
+public class RequestMappingReflectiveProcessorTests {
+
+	private final RequestMappingReflectiveProcessor processor = new RequestMappingReflectiveProcessor();
+
+	private final ReflectionHints hints = new ReflectionHints();
+
+	@Test
+	void registerReflectiveHintsForMethodWithResponseBody() throws NoSuchMethodException {
+		Method method = SampleController.class.getDeclaredMethod("get");
+		processor.registerReflectionHints(hints, method);
+		assertThat(hints.typeHints()).satisfiesExactlyInAnyOrder(
+				typeHint -> assertThat(typeHint.getType()).isEqualTo(TypeReference.of(SampleController.class)),
+				typeHint -> {
+					assertThat(typeHint.getType()).isEqualTo(TypeReference.of(Response.class));
+					assertThat(typeHint.getMemberCategories()).containsExactlyInAnyOrder(
+							MemberCategory.INVOKE_DECLARED_CONSTRUCTORS,
+							MemberCategory.DECLARED_FIELDS);
+					assertThat(typeHint.methods()).satisfiesExactlyInAnyOrder(
+							hint -> assertThat(hint.getName()).isEqualTo("getMessage"),
+							hint -> assertThat(hint.getName()).isEqualTo("setMessage"));
+				},
+				typeHint -> assertThat(typeHint.getType()).isEqualTo(TypeReference.of(String.class)));
+	}
+
+	@Test
+	void registerReflectiveHintsForMethodWithRequestBody() throws NoSuchMethodException {
+		Method method = SampleController.class.getDeclaredMethod("post", Request.class);
+		processor.registerReflectionHints(hints, method);
+		assertThat(hints.typeHints()).satisfiesExactlyInAnyOrder(
+				typeHint -> assertThat(typeHint.getType()).isEqualTo(TypeReference.of(SampleController.class)),
+				typeHint -> {
+					assertThat(typeHint.getType()).isEqualTo(TypeReference.of(Request.class));
+					assertThat(typeHint.getMemberCategories()).containsExactlyInAnyOrder(
+							MemberCategory.INVOKE_DECLARED_CONSTRUCTORS,
+							MemberCategory.DECLARED_FIELDS);
+					assertThat(typeHint.methods()).satisfiesExactlyInAnyOrder(
+							hint -> assertThat(hint.getName()).isEqualTo("getMessage"),
+							hint -> assertThat(hint.getName()).isEqualTo("setMessage"));
+				},
+				typeHint -> assertThat(typeHint.getType()).isEqualTo(TypeReference.of(String.class)));
+	}
+
+	@Test
+	void registerReflectiveHintsForMethodWithRestController() throws NoSuchMethodException {
+		Method method = SampleRestController.class.getDeclaredMethod("get");
+		processor.registerReflectionHints(hints, method);
+		assertThat(hints.typeHints()).satisfiesExactlyInAnyOrder(
+				typeHint -> assertThat(typeHint.getType()).isEqualTo(TypeReference.of(SampleRestController.class)),
+				typeHint -> {
+					assertThat(typeHint.getType()).isEqualTo(TypeReference.of(Response.class));
+					assertThat(typeHint.getMemberCategories()).containsExactlyInAnyOrder(
+							MemberCategory.INVOKE_DECLARED_CONSTRUCTORS,
+							MemberCategory.DECLARED_FIELDS);
+					assertThat(typeHint.methods()).satisfiesExactlyInAnyOrder(
+							hint -> assertThat(hint.getName()).isEqualTo("getMessage"),
+							hint -> assertThat(hint.getName()).isEqualTo("setMessage"));
+				},
+				typeHint -> assertThat(typeHint.getType()).isEqualTo(TypeReference.of(String.class)));
+	}
+
+	@Test
+	void registerReflectiveHintsForMethodWithString() throws NoSuchMethodException {
+		Method method = SampleController.class.getDeclaredMethod("message");
+		processor.registerReflectionHints(hints, method);
+		assertThat(hints.typeHints()).satisfiesExactlyInAnyOrder(
+				typeHint -> assertThat(typeHint.getType()).isEqualTo(TypeReference.of(SampleController.class)),
+				typeHint -> {
+					assertThat(typeHint.getType()).isEqualTo(TypeReference.of(String.class));
+					assertThat(typeHint.constructors()).isEmpty();
+					assertThat(typeHint.fields()).isEmpty();
+					assertThat(typeHint.methods()).isEmpty();
+				});
+	}
+
+	@Test
+	void registerReflectiveHintsForClassWithMapping() {
+		processor.registerReflectionHints(hints, SampleControllerWithClassMapping.class);
+		assertThat(hints.typeHints()).singleElement().satisfies(typeHint ->
+				assertThat(typeHint.getType()).isEqualTo(TypeReference.of(SampleControllerWithClassMapping.class)));
+	}
+
+	static class SampleController {
+
+		@GetMapping
+		@ResponseBody
+		Response get() {
+			return new Response("response");
+		}
+
+		@PostMapping
+		void post(@RequestBody Request request) {
+		}
+
+		@GetMapping
+		@ResponseBody
+		String message() {
+			return "";
+		}
+	}
+
+	@RestController
+	static class SampleRestController {
+
+		@GetMapping
+		Response get() {
+			return new Response("response");
+		}
+	}
+
+	@RequestMapping("/prefix")
+	static class SampleControllerWithClassMapping {
+	}
+
+	static class Request {
+
+		private String message;
+
+		public String getMessage() {
+			return message;
+		}
+
+		public void setMessage(String message) {
+			this.message = message;
+		}
+	}
+
+	static class Response {
+
+		private String message;
+
+		public Response(String message) {
+			this.message = message;
+		}
+
+		public String getMessage() {
+			return message;
+		}
+
+		public void setMessage(String message) {
+			this.message = message;
+		}
+	}
+}