HTTP Service proxy sets body type

Closes gh-34793

spring-web/src/main/java/org/springframework/web/client/support/RestClientAdapter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2024 the original author or authors.
+ * Copyright 2002-2025 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.
@@ -85,7 +85,8 @@ public final class RestClientAdapter implements HttpExchangeAdapter {
 		return newRequest(values).retrieve().toEntity(bodyType);
 	}
 
-	private RestClient.RequestBodySpec newRequest(HttpRequestValues values) {
+	@SuppressWarnings("unchecked")
+	private <B> RestClient.RequestBodySpec newRequest(HttpRequestValues values) {
 
 		HttpMethod httpMethod = values.getHttpMethod();
 		Assert.notNull(httpMethod, "HttpMethod is required");
@@ -123,8 +124,14 @@ public final class RestClientAdapter implements HttpExchangeAdapter {
 
 		bodySpec.attributes(attributes -> attributes.putAll(values.getAttributes()));
 
-		if (values.getBodyValue() != null) {
+		B body = (B) values.getBodyValue();
-			bodySpec.body(values.getBodyValue());
+		if (body != null) {
+			if (values.getBodyValueType() != null) {
+				bodySpec.body(body, (ParameterizedTypeReference<? super B>) values.getBodyValueType());
+			}
+			else {
+				bodySpec.body(body);
+			}
 		}
 
 		return bodySpec;

spring-web/src/main/java/org/springframework/web/client/support/RestTemplateAdapter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 the original author or authors.
+ * Copyright 2002-2025 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.
@@ -86,7 +86,7 @@ public final class RestTemplateAdapter implements HttpExchangeAdapter {
 		return this.restTemplate.exchange(newRequest(values), bodyType);
 	}
 
-	private RequestEntity<?> newRequest(HttpRequestValues values) {
+	private <B> RequestEntity<?> newRequest(HttpRequestValues values) {
 		HttpMethod httpMethod = values.getHttpMethod();
 		Assert.notNull(httpMethod, "HttpMethod is required");
 
@@ -120,11 +120,16 @@ public final class RestTemplateAdapter implements HttpExchangeAdapter {
 			builder.header(HttpHeaders.COOKIE, String.join("; ", cookies));
 		}
 
-		if (values.getBodyValue() != null) {
+		Object body = values.getBodyValue();
-			return builder.body(values.getBodyValue());
+		if (body == null) {
+			return builder.build();
 		}
 
-		return builder.build();
+		if (values.getBodyValueType() != null) {
+			return builder.body(body, values.getBodyValueType().getType());
+		}
+
+		return builder.body(body);
 	}
 
 

spring-web/src/main/java/org/springframework/web/service/invoker/HttpRequestValues.java

@@ -23,6 +23,7 @@ import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 
+import org.springframework.core.ParameterizedTypeReference;
 import org.springframework.http.HttpEntity;
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpMethod;
@@ -75,6 +76,9 @@ public class HttpRequestValues {
 	@Nullable
 	private final Object bodyValue;
 
+	@Nullable
+	private ParameterizedTypeReference<?> bodyValueType;
+
 
 	/**
 	 * Construct {@link HttpRequestValues}.
@@ -177,6 +181,15 @@ public class HttpRequestValues {
 		return this.bodyValue;
 	}
 
+	/**
+	 * Return the type for the {@linkplain #getBodyValue() body value}.
+	 * @since 6.2.7
+	 */
+	@Nullable
+	public ParameterizedTypeReference<?> getBodyValueType() {
+		return this.bodyValueType;
+	}
+
 
 	public static Builder builder() {
 		return new Builder();
@@ -253,6 +266,9 @@ public class HttpRequestValues {
 		@Nullable
 		private Object bodyValue;
 
+		@Nullable
+		private ParameterizedTypeReference<?> bodyValueType;
+
 		/**
 		 * Set the HTTP method for the request.
 		 */
@@ -389,6 +405,15 @@ public class HttpRequestValues {
 			this.bodyValue = bodyValue;
 		}
 
+		/**
+		 * Variant of {@link #setBodyValue(Object)} with the body type.
+		 * @since 6.2.7
+		 */
+		public void setBodyValue(@Nullable Object bodyValue, @Nullable ParameterizedTypeReference<?> valueType) {
+			setBodyValue(bodyValue);
+			this.bodyValueType = valueType;
+		}
+
 
 		// Implementation of {@link Metadata} methods
 
@@ -465,9 +490,14 @@ public class HttpRequestValues {
 			Map<String, Object> attributes = (this.attributes != null ?
 					new HashMap<>(this.attributes) : Collections.emptyMap());
 
-			return createRequestValues(
+			HttpRequestValues requestValues = createRequestValues(
 					this.httpMethod, uri, uriBuilderFactory, uriTemplate, uriVars,
 					headers, cookies, attributes, bodyValue);
+
+			// In 6.2.x only, temporarily work around protected methods
+			requestValues.bodyValueType = this.bodyValueType;
+
+			return requestValues;
 		}
 
 		protected boolean hasParts() {

spring-web/src/main/java/org/springframework/web/service/invoker/RequestBodyArgumentResolver.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2024 the original author or authors.
+ * Copyright 2002-2025 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.
@@ -83,15 +83,16 @@ public class RequestBodyArgumentResolver implements HttpServiceArgumentResolver
 		if (this.reactiveAdapterRegistry != null) {
 			ReactiveAdapter adapter = this.reactiveAdapterRegistry.getAdapter(parameter.getParameterType());
 			if (adapter != null) {
-				MethodParameter nestedParameter = parameter.nested();
+				MethodParameter nestedParam = parameter.nested();
 
 				String message = "Async type for @RequestBody should produce value(s)";
 				Assert.isTrue(!adapter.isNoValue(), message);
-				Assert.isTrue(nestedParameter.getNestedParameterType() != Void.class, message);
+				Assert.isTrue(nestedParam.getNestedParameterType() != Void.class, message);
 
-				if (requestValues instanceof ReactiveHttpRequestValues.Builder reactiveRequestValues) {
+				if (requestValues instanceof ReactiveHttpRequestValues.Builder rrv) {
-					reactiveRequestValues.setBodyPublisher(
+					rrv.setBodyPublisher(
-							adapter.toPublisher(argument), asParameterizedTypeRef(nestedParameter));
+							adapter.toPublisher(argument),
+							ParameterizedTypeReference.forType(nestedParam.getNestedGenericParameterType()));
 				}
 				else {
 					throw new IllegalStateException(
@@ -103,12 +104,8 @@ public class RequestBodyArgumentResolver implements HttpServiceArgumentResolver
 		}
 
 		// Not a reactive type
-		requestValues.setBodyValue(argument);
+		requestValues.setBodyValue(argument, ParameterizedTypeReference.forType(parameter.getGenericParameterType()));
 		return true;
 	}
 
-	private static ParameterizedTypeReference<Object> asParameterizedTypeRef(MethodParameter nestedParam) {
-		return ParameterizedTypeReference.forType(nestedParam.getNestedGenericParameterType());
-	}
-
 }

spring-web/src/test/java/org/springframework/web/client/support/RestClientAdapterTests.java

@@ -22,7 +22,9 @@ import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 import java.net.URI;
+import java.util.LinkedHashSet;
 import java.util.Optional;
+import java.util.Set;
 import java.util.function.BiFunction;
 import java.util.stream.Stream;
 
@@ -267,6 +269,19 @@ class RestClientAdapterTests {
 		assertThat(this.anotherServer.getRequestCount()).isEqualTo(0);
 	}
 
+	@ParameterizedAdapterTest // gh-34793
+	void postSet(MockWebServer server, Service service) throws InterruptedException {
+		Set<Person> persons = new LinkedHashSet<>();
+		persons.add(new Person("John"));
+		persons.add(new Person("Richard"));
+		service.postPersonSet(persons);
+
+		RecordedRequest request = server.takeRequest();
+		assertThat(request.getMethod()).isEqualTo("POST");
+		assertThat(request.getPath()).isEqualTo("/persons");
+		assertThat(request.getBody().readUtf8()).isEqualTo("[{\"name\":\"John\"},{\"name\":\"Richard\"}]");
+	}
+
 
 	private static MockWebServer anotherServer() {
 		MockWebServer server = new MockWebServer();
@@ -297,6 +312,9 @@ class RestClientAdapterTests {
 		@PostExchange
 		void postMultipart(MultipartFile file, @RequestPart String anotherPart);
 
+		@PostExchange(url = "/persons", contentType = MediaType.APPLICATION_JSON_VALUE)
+		void postPersonSet(@RequestBody Set<Person> set);
+
 		@PutExchange
 		void putWithCookies(@CookieValue String firstCookie, @CookieValue String secondCookie);
 
@@ -315,4 +333,19 @@ class RestClientAdapterTests {
 		ResponseEntity<String> getWithIgnoredUriBuilderFactory(URI uri, UriBuilderFactory uriBuilderFactory);
 	}
 
+
+	static final class Person {
+
+		private final String name;
+
+		Person(String name) {
+			this.name = name;
+		}
+
+		public String getName() {
+			return this.name;
+		}
+
+	}
+
 }

spring-web/src/test/java/org/springframework/web/service/invoker/RequestBodyArgumentResolverTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2024 the original author or authors.
+ * Copyright 2002-2025 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.
@@ -54,6 +54,7 @@ class RequestBodyArgumentResolverTests {
 		this.service.execute(body);
 
 		assertThat(getBodyValue()).isEqualTo(body);
+		assertThat(getBodyValueType()).isEqualTo(new ParameterizedTypeReference<String>() {});
 		assertThat(getPublisherBody()).isNull();
 	}
 
@@ -173,6 +174,11 @@ class RequestBodyArgumentResolverTests {
 		return getReactiveRequestValues().getBodyValue();
 	}
 
+	@Nullable
+	private ParameterizedTypeReference<?> getBodyValueType() {
+		return getReactiveRequestValues().getBodyValueType();
+	}
+
 	@Nullable
 	private Publisher<?> getPublisherBody() {
 		return getReactiveRequestValues().getBodyPublisher();

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2024 the original author or authors.
+ * Copyright 2002-2025 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.
@@ -98,8 +98,8 @@ public final class WebClientAdapter extends AbstractReactorHttpExchangeAdapter {
 		return newRequest(requestValues).retrieve().toEntityFlux(bodyType);
 	}
 
-	@SuppressWarnings("ReactiveStreamsUnusedPublisher")
+	@SuppressWarnings({"ReactiveStreamsUnusedPublisher", "unchecked"})
-	private WebClient.RequestBodySpec newRequest(HttpRequestValues values) {
+	private <B> WebClient.RequestBodySpec newRequest(HttpRequestValues values) {
 
 		HttpMethod httpMethod = values.getHttpMethod();
 		Assert.notNull(httpMethod, "HttpMethod is required");
@@ -130,12 +130,18 @@ public final class WebClientAdapter extends AbstractReactorHttpExchangeAdapter {
 		bodySpec.attributes(attributes -> attributes.putAll(values.getAttributes()));
 
 		if (values.getBodyValue() != null) {
-			bodySpec.bodyValue(values.getBodyValue());
+			if (values.getBodyValueType() != null) {
+				B body = (B) values.getBodyValue();
+				bodySpec.bodyValue(body, (ParameterizedTypeReference<B>) values.getBodyValueType());
+			}
+			else {
+				bodySpec.bodyValue(values.getBodyValue());
+			}
 		}
-		else if (values instanceof ReactiveHttpRequestValues reactiveRequestValues) {
+		else if (values instanceof ReactiveHttpRequestValues rhrv) {
-			Publisher<?> body = reactiveRequestValues.getBodyPublisher();
+			Publisher<?> body = rhrv.getBodyPublisher();
 			if (body != null) {
-				ParameterizedTypeReference<?> elementType = reactiveRequestValues.getBodyPublisherElementType();
+				ParameterizedTypeReference<?> elementType = rhrv.getBodyPublisherElementType();
 				Assert.notNull(elementType, "Publisher body element type is required");
 				bodySpec.body(body, elementType);
 			}

spring-webflux/src/test/java/org/springframework/web/reactive/function/client/support/WebClientAdapterTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2024 the original author or authors.
+ * Copyright 2002-2025 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.
@@ -21,7 +21,9 @@ import java.io.IOException;
 import java.net.URI;
 import java.time.Duration;
 import java.util.HashMap;
+import java.util.LinkedHashSet;
 import java.util.Map;
+import java.util.Set;
 import java.util.function.Consumer;
 
 import okhttp3.mockwebserver.MockResponse;
@@ -39,6 +41,7 @@ import org.springframework.util.LinkedMultiValueMap;
 import org.springframework.util.MultiValueMap;
 import org.springframework.web.bind.annotation.PathVariable;
 import org.springframework.web.bind.annotation.RequestAttribute;
+import org.springframework.web.bind.annotation.RequestBody;
 import org.springframework.web.bind.annotation.RequestParam;
 import org.springframework.web.bind.annotation.RequestPart;
 import org.springframework.web.multipart.MultipartFile;
@@ -168,6 +171,22 @@ class WebClientAdapterTests {
 						"Content-Type: text/plain;charset=UTF-8", "Content-Length: 5", "test2");
 	}
 
+	@Test // gh-34793
+	void postSet() throws InterruptedException {
+		prepareResponse(response -> response.setResponseCode(201));
+
+		Set<Person> persons = new LinkedHashSet<>();
+		persons.add(new Person("John"));
+		persons.add(new Person("Richard"));
+
+		initService().postPersonSet(persons);
+
+		RecordedRequest request = server.takeRequest();
+		assertThat(request.getMethod()).isEqualTo("POST");
+		assertThat(request.getPath()).isEqualTo("/persons");
+		assertThat(request.getBody().readUtf8()).isEqualTo("[{\"name\":\"John\"},{\"name\":\"Richard\"}]");
+	}
+
 	@Test
 	void uriBuilderFactory() throws Exception {
 		String ignoredResponseBody = "hello";
@@ -251,6 +270,9 @@ class WebClientAdapterTests {
 		@PostExchange
 		void postMultipart(MultipartFile file, @RequestPart String anotherPart);
 
+		@PostExchange("/persons")
+		void postPersonSet(@RequestBody Set<Person> set);
+
 		@GetExchange("/greeting")
 		String getWithUriBuilderFactory(UriBuilderFactory uriBuilderFactory);
 
@@ -263,4 +285,19 @@ class WebClientAdapterTests {
 
 	}
 
+
+	static final class Person {
+
+		private final String name;
+
+		Person(String name) {
+			this.name = name;
+		}
+
+		public String getName() {
+			return this.name;
+		}
+
+	}
+
 }