Update contribution

Closes gh-33220

Author: rstoyanchev

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

@@ -129,7 +129,7 @@ private NamedValueInfo getNamedValueInfo(MethodParameter parameter, HttpRequestV
 	 */
 	@Nullable
 	protected NamedValueInfo createNamedValueInfo(
-			MethodParameter parameter, HttpRequestValues.Metadata requestValues) {
+			MethodParameter parameter, HttpRequestValues.Metadata metadata) {
 
 		return createNamedValueInfo(parameter);
 	}
@@ -246,6 +246,8 @@ protected static class NamedValueInfo {
 		 * @param required whether it is marked as required
 		 * @param defaultValue fallback value, possibly {@link ValueConstants#DEFAULT_NONE}
 		 * @param label how it should appear in error messages, e.g. "path variable", "request header"
+		 * @param multiValued whether this argument resolver supports sending multiple values;
+		 * if not, then multiple values are formatted as a String value
 		 */
 		public NamedValueInfo(
 				String name, boolean required, @Nullable String defaultValue, String label, boolean multiValued) {

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

@@ -55,61 +55,79 @@
  */
 public class RequestParamArgumentResolver extends AbstractNamedValueArgumentResolver {
 
-	private boolean formatAsSingleValue = true;
+	private boolean favorSingleValue;
 
 
 	public RequestParamArgumentResolver(ConversionService conversionService) {
 		super(conversionService);
 	}
 
-	public RequestParamArgumentResolver(ConversionService conversionService, boolean formatAsSingleValue) {
-		super(conversionService);
-		this.formatAsSingleValue = formatAsSingleValue;
-	}
-
 
-	@Override
-	@Nullable
-	protected NamedValueInfo createNamedValueInfo(MethodParameter parameter, HttpRequestValues.Metadata requestValues) {
-		MediaType contentType = requestValues.getContentType();
-		if (contentType != null && isMultiValueFormContentType(contentType)) {
-			this.formatAsSingleValue = true;
-		}
+	/**
+	 * Whether to format multiple values (e.g. collection, array) as a single
+	 * String value through the configured {@link ConversionService} unless the
+	 * content type is form data, or it is a multipart request.
+	 * <p>By default, this is {@code false} in which case formatting is not applied,
+	 * and a separate parameter with the same name is created for each value.
+	 * @since 6.2
+	 */
+	public void setFavorSingleValue(boolean favorSingleValue) {
+		this.favorSingleValue = favorSingleValue;
+	}
 
-		return createNamedValueInfo(parameter);
+	/**
+	 * Return the setting for {@link #setFavorSingleValue favorSingleValue}.
+	 * @since 6.2
+	 */
+	public boolean isFavorSingleValue() {
+		return this.favorSingleValue;
 	}
 
+
 	@Override
 	@Nullable
-	protected NamedValueInfo createNamedValueInfo(MethodParameter parameter) {
+	protected NamedValueInfo createNamedValueInfo(MethodParameter parameter, HttpRequestValues.Metadata metadata) {
 		RequestParam annot = parameter.getParameterAnnotation(RequestParam.class);
 		if (annot == null) {
 			return null;
 		}
-
-		return (annot == null ? null :
-				new NamedValueInfo(annot.name(), annot.required(), annot.defaultValue(),
-						"request parameter", this.formatAsSingleValue));
+		return new NamedValueInfo(
+				annot.name(), annot.required(), annot.defaultValue(), "request parameter",
+				supportsMultipleValues(parameter, metadata));
 	}
 
 	@Override
-	protected void addRequestValue(
-			String name, Object value, MethodParameter parameter, HttpRequestValues.Builder requestValues) {
-
-		requestValues.addRequestParameter(name, (String) value);
+	protected NamedValueInfo createNamedValueInfo(MethodParameter parameter) {
+		// Shouldn't be called since we override createNamedValueInfo with HttpRequestValues.Metadata
+		throw new UnsupportedOperationException();
 	}
 
-	protected boolean isFormatAsSingleValue() {
-		return this.formatAsSingleValue;
+	/**
+	 * Determine whether the resolver should send multi-value request parameters
+	 * as individual values. If not, they are formatted to a single String value.
+	 * The default implementation uses {@link #isFavorSingleValue()} to decide
+	 * unless the content type is form data, or it is a multipart request.
+	 * @since 6.2
+	 */
+	protected boolean supportsMultipleValues(MethodParameter parameter, HttpRequestValues.Metadata metadata) {
+		return (!isFavorSingleValue() || isFormOrMultipartContent(metadata));
 	}
 
-	protected void setFormatAsSingleValue(boolean formatAsSingleValue) {
-		this.formatAsSingleValue = formatAsSingleValue;
+	/**
+	 * Whether the content type is form data, or it is a multipart request.
+	 * @since 6.2
+	 */
+	protected boolean isFormOrMultipartContent(HttpRequestValues.Metadata metadata) {
+		MediaType mediaType = metadata.getContentType();
+		return (mediaType != null && (mediaType.getType().equals("multipart") ||
+				mediaType.isCompatibleWith(MediaType.APPLICATION_FORM_URLENCODED)));
 	}
 
-	protected boolean isMultiValueFormContentType(MediaType contentType) {
-		return contentType.equals(MediaType.APPLICATION_FORM_URLENCODED)
-				|| contentType.getType().equals("multipart");
+	@Override
+	protected void addRequestValue(
+			String name, Object value, MethodParameter parameter, HttpRequestValues.Builder requestValues) {
+
+		requestValues.addRequestParameter(name, (String) value);
 	}
 
 }

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

@@ -16,17 +16,18 @@
 
 package org.springframework.web.service.invoker;
 
-import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 
 import org.junit.jupiter.api.Test;
 
-import org.springframework.core.convert.ConversionService;
 import org.springframework.core.convert.support.DefaultConversionService;
 import org.springframework.util.MultiValueMap;
 import org.springframework.web.bind.annotation.RequestParam;
 import org.springframework.web.service.annotation.GetExchange;
 import org.springframework.web.service.annotation.PostExchange;
+import org.springframework.web.util.UriComponents;
+import org.springframework.web.util.UriComponentsBuilder;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
@@ -62,24 +63,18 @@ void requestParam() {
 	}
 
 	@Test
-	@SuppressWarnings("unchecked")
 	void requestParamWithDisabledFormattingCollectionValue() {
-		ConversionService conversionService = new DefaultConversionService();
-		boolean formatAsSingleValue = false;
-		Service service = builder.customArgumentResolver(
-						new RequestParamArgumentResolver(conversionService, formatAsSingleValue))
-				.build()
-				.createClient(Service.class);
-		List<String> collectionParams = List.of("1", "2", "3");
-		service.getForm("value 1", collectionParams);
-
-		Object uriVariables = this.client.getRequestValues().getUriVariables();
-		assertThat(uriVariables).isNotInstanceOf(MultiValueMap.class).isInstanceOf(HashMap.class);
-		assertThat((HashMap<String, String>) uriVariables).hasSize(4)
-				.containsEntry("queryParam0", "param1")
-				.containsEntry("queryParam0[0]", "value 1")
-				.containsEntry("queryParam1", "param2")
-				.containsEntry("queryParam1[0]", String.join(",", collectionParams));
+		RequestParamArgumentResolver resolver = new RequestParamArgumentResolver(new DefaultConversionService());
+		resolver.setFavorSingleValue(true);
+
+		Service service = builder.customArgumentResolver(resolver).build().createClient(Service.class);
+		service.getWithParams("value 1", List.of("1", "2", "3"));
+
+		HttpRequestValues values = this.client.getRequestValues();
+		String uriTemplate = values.getUriTemplate();
+		Map<String, String> uriVariables = values.getUriVariables();
+		UriComponents uri = UriComponentsBuilder.fromUriString(uriTemplate).buildAndExpand(uriVariables).encode();
+		assertThat(uri.getQuery()).isEqualTo("param1=value%201&param2=1,2,3");
 	}
 
 	private interface Service {
@@ -88,7 +83,7 @@ private interface Service {
 		void postForm(@RequestParam String param1, @RequestParam String param2);
 
 		@GetExchange
-		void getForm(@RequestParam String param1, @RequestParam List<String> param2);
+		void getWithParams(@RequestParam String param1, @RequestParam List<String> param2);
 	}
 
 }