#1223 - Provide API to configure RestTemplate with hypermedia.

Create a HypermediaRestTemplateConfigurer bean registered as a Spring HATEOAS bean.

Update reference documentation to show how to use it directly and with Spring Boot via RestTemplateCustomizer.

src/test/java/org/springframework/hateoas/config/HypermediaRestTemplateConfigurerTest.java

@@ -0,0 +1,81 @@
+package org.springframework.hateoas.config;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.context.annotation.Bean;
+import org.springframework.hateoas.MediaTypes;
+import org.springframework.http.MediaType;
+import org.springframework.http.converter.HttpMessageConverter;
+import org.springframework.web.client.RestTemplate;
+
+import java.util.Collections;
+
+import static org.assertj.core.api.Assertions.*;
+import static org.springframework.hateoas.config.EnableHypermediaSupport.HypermediaType.*;
+import static org.springframework.hateoas.support.ContextTester.*;
+
+public class HypermediaRestTemplateConfigurerTest {
+
+	private static MediaType FRODO_JSON = MediaType.parseMediaType("application/frodo+json");
+
+	@Test // #1223
+	void webConvertersShouldAddHypermediaMessageConverters() {
+
+		withContext(HalConfig.class, context -> {
+
+			HypermediaRestTemplateConfigurer configurer = context.getBean(HypermediaRestTemplateConfigurer.class);
+
+			RestTemplate restTemplate = configurer.registerHypermediaTypes(new RestTemplate());
+
+			assertThat(restTemplate.getMessageConverters()).flatExtracting(HttpMessageConverter::getSupportedMediaTypes)
+					.contains(MediaTypes.HAL_JSON) //
+					.doesNotContain(MediaTypes.HAL_FORMS_JSON, MediaTypes.COLLECTION_JSON, MediaTypes.UBER_JSON);
+		});
+	}
+
+	@Test // #1223
+	void webConvertersShouldAddAllHypermediaMessageConverters() {
+
+		withContext(AllHypermediaConfig.class, context -> {
+
+			HypermediaRestTemplateConfigurer configurer = context.getBean(HypermediaRestTemplateConfigurer.class);
+
+			RestTemplate restTemplate = configurer.registerHypermediaTypes(new RestTemplate());
+
+			assertThat(restTemplate.getMessageConverters()).flatExtracting(HttpMessageConverter::getSupportedMediaTypes)
+					.contains(MediaTypes.HAL_JSON, MediaTypes.HAL_FORMS_JSON, MediaTypes.COLLECTION_JSON, MediaTypes.UBER_JSON);
+		});
+	}
+
+	@Test // #1223
+	void webConvertersShouldSupportCustomHypermediaTypes() {
+
+		withContext(CustomHypermediaConfig.class, context -> {
+
+			HypermediaRestTemplateConfigurer configurer = context.getBean(HypermediaRestTemplateConfigurer.class);
+
+			RestTemplate restTemplate = configurer.registerHypermediaTypes(new RestTemplate());
+
+			assertThat(restTemplate.getMessageConverters()).flatExtracting(HttpMessageConverter::getSupportedMediaTypes)
+					.contains(MediaTypes.HAL_JSON, FRODO_JSON)
+					.doesNotContain(MediaTypes.HAL_FORMS_JSON, MediaTypes.COLLECTION_JSON, MediaTypes.UBER_JSON);
+		});
+	}
+
+	@EnableHypermediaSupport(type = HAL)
+	static class HalConfig {
+
+	}
+
+	@EnableHypermediaSupport(type = { HAL, HAL_FORMS, COLLECTION_JSON, UBER })
+	static class AllHypermediaConfig {
+
+	}
+
+	static class CustomHypermediaConfig extends HalConfig {
+
+		@Bean
+		HypermediaMappingInformation hypermediaMappingInformation() {
+			return () -> Collections.singletonList(FRODO_JSON);
+		}
+	}
+}