Simplify form data handling in HttpRequestValues

Closes gh-29615

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

@@ -17,14 +17,11 @@
 package org.springframework.web.service.invoker;
 
 import java.net.URI;
-import java.nio.charset.Charset;
-import java.nio.charset.StandardCharsets;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
-import java.util.function.Function;
 
 import org.reactivestreams.Publisher;
 
@@ -34,7 +31,6 @@
 import org.springframework.http.HttpMethod;
 import org.springframework.http.MediaType;
 import org.springframework.http.client.MultipartBodyBuilder;
-import org.springframework.http.codec.FormHttpMessageWriter;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.CollectionUtils;
@@ -202,8 +198,6 @@ public static Builder builder() {
 	 */
 	public final static class Builder {
 
-		private static final Function<MultiValueMap<String, String>, byte[]> FORM_DATA_SERIALIZER = new FormDataSerializer();
-
 		@Nullable
 		private HttpMethod httpMethod;
 
@@ -403,7 +397,7 @@ public HttpRequestValues build() {
 
 				if (isFormData) {
 					Assert.isTrue(bodyValue == null && this.body == null, "Expected body or request params, not both");
-					bodyValue = FORM_DATA_SERIALIZER.apply(this.requestParams);
+					bodyValue = new LinkedMultiValueMap<>(this.requestParams);
 				}
 				else if (uri != null) {
 					uri = UriComponentsBuilder.fromUri(uri)
@@ -458,16 +452,4 @@ private String appendQueryParams(
 
 	}
 
-
-	private static class FormDataSerializer
-			extends FormHttpMessageWriter implements Function<MultiValueMap<String, String>, byte[]> {
-
-		@Override
-		public byte[] apply(MultiValueMap<String, String> requestParams) {
-			Charset charset = StandardCharsets.UTF_8;
-			return serializeForm(requestParams, charset).getBytes(charset);
-		}
-
-	}
-
 }

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

@@ -17,6 +17,7 @@
 package org.springframework.web.service.invoker;
 
 import java.net.URI;
+import java.util.List;
 
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
@@ -29,7 +30,6 @@
 import org.springframework.util.MultiValueMap;
 import org.springframework.web.util.UriComponentsBuilder;
 
-import static java.nio.charset.StandardCharsets.UTF_8;
 import static org.assertj.core.api.Assertions.assertThat;
 
 /**
@@ -58,8 +58,9 @@ void requestParamAsFormData(String httpMethod) {
 				.build();
 
 		Object body = requestValues.getBodyValue();
-		assertThat(body).isNotNull().isInstanceOf(byte[].class);
-		assertThat(new String((byte[]) body, UTF_8)).isEqualTo("param1=1st+value&param2=2nd+value+A&param2=2nd+value+B");
+		assertThat((MultiValueMap<String, String>) body).hasSize(2)
+				.containsEntry("param1", List.of("1st value"))
+				.containsEntry("param2", List.of("2nd value A", "2nd value B"));
 	}
 
 	@Test

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

@@ -16,13 +16,15 @@
 
 package org.springframework.web.service.invoker;
 
+import java.util.List;
+
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
+import org.springframework.util.MultiValueMap;
 import org.springframework.web.bind.annotation.RequestParam;
 import org.springframework.web.service.annotation.PostExchange;
 
-import static java.nio.charset.StandardCharsets.UTF_8;
 import static org.assertj.core.api.Assertions.assertThat;
 
 /**
@@ -58,8 +60,10 @@ void requestParam() {
 		this.service.postForm("value 1", "value 2");
 
 		Object body = this.client.getRequestValues().getBodyValue();
-		assertThat(body).isNotNull().isInstanceOf(byte[].class);
-		assertThat(new String((byte[]) body, UTF_8)).isEqualTo("param1=value+1&param2=value+2");
+		assertThat(body).isNotNull().isInstanceOf(MultiValueMap.class);
+		assertThat((MultiValueMap<String, String>) body).hasSize(2)
+				.containsEntry("param1", List.of("value 1"))
+				.containsEntry("param2", List.of("value 2"));
 	}
 
 

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

@@ -26,17 +26,22 @@
 
 import okhttp3.mockwebserver.MockResponse;
 import okhttp3.mockwebserver.MockWebServer;
+import okhttp3.mockwebserver.RecordedRequest;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import reactor.core.publisher.Mono;
 import reactor.test.StepVerifier;
 
 import org.springframework.lang.Nullable;
+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.RequestParam;
 import org.springframework.web.reactive.function.client.WebClient;
 import org.springframework.web.service.annotation.GetExchange;
+import org.springframework.web.service.annotation.PostExchange;
 import org.springframework.web.service.invoker.HttpServiceProxyFactory;
 
 import static org.assertj.core.api.Assertions.assertThat;
@@ -68,8 +73,7 @@ void shutdown() throws IOException {
 
 
 	@Test
-	void greeting() throws Exception {
-
+	void greeting() {
 		prepareResponse(response ->
 				response.setHeader("Content-Type", "text/plain").setBody("Hello Spring!"));
 
@@ -81,7 +85,6 @@ void greeting() throws Exception {
 
 	@Test
 	void greetingWithRequestAttribute() {
-
 		Map<String, Object> attributes = new HashMap<>();
 
 		WebClient webClient = WebClient.builder()
@@ -115,6 +118,21 @@ void uri() throws Exception {
 		assertThat(this.server.takeRequest().getRequestUrl().uri()).isEqualTo(dynamicUri);
 	}
 
+	@Test
+	void formData() throws Exception {
+		prepareResponse(response -> response.setResponseCode(201));
+
+		MultiValueMap<String, String> map = new LinkedMultiValueMap<>();
+		map.add("param1", "value 1");
+		map.add("param2", "value 2");
+
+		initHttpService().postForm(map);
+
+		RecordedRequest request = this.server.takeRequest();
+		assertThat(request.getHeaders().get("Content-Type")).isEqualTo("application/x-www-form-urlencoded;charset=UTF-8");
+		assertThat(request.getBody().readUtf8()).isEqualTo("param1=value+1&param2=value+2");
+	}
+
 	private TestHttpService initHttpService() {
 		WebClient webClient = WebClient.builder().baseUrl(this.server.url("/").toString()).build();
 		return initHttpService(webClient);
@@ -145,6 +163,9 @@ private interface TestHttpService {
 		@GetExchange("/greetings/{id}")
 		String getGreetingById(@Nullable URI uri, @PathVariable String id);
 
+		@PostExchange(contentType = "application/x-www-form-urlencoded")
+		void postForm(@RequestParam MultiValueMap<String, String> params);
+
 	}
 
 }