Add WebExchangeDataBinder

Issue: SPR-14541

spring-web-reactive/src/main/java/org/springframework/web/reactive/config/WebReactiveConfiguration.java

@@ -55,7 +55,10 @@ import org.springframework.http.codec.xml.Jaxb2XmlDecoder;
 import org.springframework.http.codec.xml.Jaxb2XmlEncoder;
 import org.springframework.util.ClassUtils;
 import org.springframework.validation.Errors;
+import org.springframework.validation.MessageCodesResolver;
 import org.springframework.validation.Validator;
+import org.springframework.web.bind.WebDataBinder;
+import org.springframework.web.bind.support.ConfigurableWebBindingInitializer;
 import org.springframework.web.cors.CorsConfiguration;
 import org.springframework.web.reactive.HandlerMapping;
 import org.springframework.web.reactive.accept.CompositeContentTypeResolver;
@@ -255,6 +258,7 @@ public class WebReactiveConfiguration implements ApplicationContextAware {
 		}
 
 		adapter.setMessageReaders(getMessageReaders());
+		adapter.setWebBindingInitializer(getConfigurableWebBindingInitializer());
 		adapter.setConversionService(mvcConversionService());
 		adapter.setValidator(mvcValidator());
 
@@ -325,6 +329,18 @@ public class WebReactiveConfiguration implements ApplicationContextAware {
 	protected void extendMessageReaders(List<HttpMessageReader<?>> messageReaders) {
 	}
 
+	/**
+	 * Return the {@link ConfigurableWebBindingInitializer} to use for
+	 * initializing all {@link WebDataBinder} instances.
+	 */
+	protected ConfigurableWebBindingInitializer getConfigurableWebBindingInitializer() {
+		ConfigurableWebBindingInitializer initializer = new ConfigurableWebBindingInitializer();
+		initializer.setConversionService(mvcConversionService());
+		initializer.setValidator(mvcValidator());
+		initializer.setMessageCodesResolver(getMessageCodesResolver());
+		return initializer;
+	}
+
 	@Bean
 	public FormattingConversionService mvcConversionService() {
 		FormattingConversionService service = new DefaultFormattingConversionService();
@@ -378,6 +394,13 @@ public class WebReactiveConfiguration implements ApplicationContextAware {
 		return null;
 	}
 
+	/**
+	 * Override this method to provide a custom {@link MessageCodesResolver}.
+	 */
+	protected MessageCodesResolver getMessageCodesResolver() {
+		return null;
+	}
+
 	@Bean
 	public SimpleHandlerAdapter simpleHandlerAdapter() {
 		return new SimpleHandlerAdapter();

spring-web-reactive/src/main/java/org/springframework/web/reactive/result/method/annotation/RequestMappingHandlerAdapter.java

@@ -41,6 +41,7 @@ import org.springframework.http.codec.HttpMessageReader;
 import org.springframework.ui.ExtendedModelMap;
 import org.springframework.ui.ModelMap;
 import org.springframework.validation.Validator;
+import org.springframework.web.bind.support.WebBindingInitializer;
 import org.springframework.web.method.HandlerMethod;
 import org.springframework.web.method.annotation.ExceptionHandlerMethodResolver;
 import org.springframework.web.reactive.HandlerAdapter;
@@ -68,6 +69,8 @@ public class RequestMappingHandlerAdapter implements HandlerAdapter, BeanFactory
 
 	private ReactiveAdapterRegistry reactiveAdapters = new ReactiveAdapterRegistry();
 
+	private WebBindingInitializer webBindingInitializer;
+
 	private ConversionService conversionService = new DefaultFormattingConversionService();
 
 	private Validator validator;
@@ -136,6 +139,21 @@ public class RequestMappingHandlerAdapter implements HandlerAdapter, BeanFactory
 		return this.reactiveAdapters;
 	}
 
+	/**
+	 * Provide a WebBindingInitializer with "global" initialization to apply
+	 * to every DataBinder instance.
+	 */
+	public void setWebBindingInitializer(WebBindingInitializer webBindingInitializer) {
+		this.webBindingInitializer = webBindingInitializer;
+	}
+
+	/**
+	 * Return the configured WebBindingInitializer, or {@code null} if none.
+	 */
+	public WebBindingInitializer getWebBindingInitializer() {
+		return this.webBindingInitializer;
+	}
+
 	/**
 	 * Configure a ConversionService for type conversion of controller method
 	 * arguments as well as for converting from different async types to

spring-web-reactive/src/test/java/org/springframework/web/reactive/config/WebReactiveConfigurationTests.java

@@ -49,6 +49,8 @@ import org.springframework.util.MimeType;
 import org.springframework.util.MimeTypeUtils;
 import org.springframework.validation.Validator;
 import org.springframework.validation.beanvalidation.OptionalValidatorFactoryBean;
+import org.springframework.web.bind.WebExchangeDataBinder;
+import org.springframework.web.bind.support.WebBindingInitializer;
 import org.springframework.web.reactive.accept.RequestedContentTypeResolver;
 import org.springframework.web.reactive.handler.AbstractHandlerMapping;
 import org.springframework.web.reactive.handler.SimpleUrlHandlerMapping;
@@ -161,6 +163,13 @@ public class WebReactiveConfigurationTests {
 		Validator validator = context.getBean(name, Validator.class);
 		assertSame(validator, adapter.getValidator());
 		assertEquals(OptionalValidatorFactoryBean.class, validator.getClass());
+
+		WebBindingInitializer bindingInitializer = adapter.getWebBindingInitializer();
+		assertNotNull(bindingInitializer);
+		WebExchangeDataBinder binder = new WebExchangeDataBinder(new Object());
+		bindingInitializer.initBinder(binder);
+		assertSame(service, binder.getConversionService());
+		assertSame(validator, binder.getValidator());
 	}
 
 	@Test