SPR-6709 Support @Valid with @RequestBody method arguments

org.springframework.web.servlet/src/main/java/org/springframework/web/servlet/mvc/method/annotation/support/RequestBodyNotValidException.java

@@ -0,0 +1,48 @@
+/*
+ * Copyright 2002-2011 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.web.servlet.mvc.method.annotation.support;
+
+import org.springframework.validation.Errors;
+import org.springframework.web.bind.annotation.RequestBody;
+
+/**
+ * Thrown by {@link RequestResponseBodyMethodProcessor} when an @{@link RequestBody} argument annotated with 
+ * {@code @Valid} results in validation errors.
+ * 
+ * @author Rossen Stoyanchev
+ * @since 3.1
+ */
+@SuppressWarnings("serial")
+public class RequestBodyNotValidException extends RuntimeException {
+
+	private final Errors errors;
+
+	/**
+	 * @param errors contains the results of validating an @{@link RequestBody} argument.
+	 */
+	public RequestBodyNotValidException(Errors errors) {
+		this.errors = errors;
+	}
+
+	/**
+	 * Returns an Errors instance with validation errors. 
+	 */
+	public Errors getErrors() {
+		return errors;
+	}
+	
+}

org.springframework.web.servlet/src/main/java/org/springframework/web/servlet/mvc/method/annotation/support/RequestResponseBodyMethodProcessor.java

@@ -17,21 +17,30 @@
 package org.springframework.web.servlet.mvc.method.annotation.support;
 
 import java.io.IOException;
+import java.lang.annotation.Annotation;
 import java.util.List;
 
+import org.springframework.core.Conventions;
 import org.springframework.core.MethodParameter;
 import org.springframework.http.converter.HttpMessageConverter;
+import org.springframework.validation.Errors;
+import org.springframework.validation.Validator;
 import org.springframework.web.HttpMediaTypeNotAcceptableException;
-import org.springframework.web.HttpMediaTypeNotSupportedException;
+import org.springframework.web.bind.WebDataBinder;
 import org.springframework.web.bind.annotation.RequestBody;
 import org.springframework.web.bind.annotation.ResponseBody;
 import org.springframework.web.bind.support.WebDataBinderFactory;
 import org.springframework.web.context.request.NativeWebRequest;
 import org.springframework.web.method.support.ModelAndViewContainer;
+import org.springframework.web.servlet.config.annotation.EnableWebMvc;
 
 /**
- * Resolves method arguments annotated with @{@link RequestBody}. Handles return values from methods annotated with 
- * {@link ResponseBody}.
+ * Resolves method arguments annotated with @{@link RequestBody} and handles return values from methods 
+ * annotated with {@link ResponseBody}. 
+ * 
+ * <p>An @{@link RequestBody} method argument will be validated if annotated with {@code @Valid}. A 
+ * {@link Validator} instance can be configured globally in XML configuration with the Spring MVC namespace 
+ * or in Java-based configuration with @{@link EnableWebMvc}.
  * 
  * @author Arjen Poutsma
  * @author Rossen Stoyanchev
@@ -54,11 +63,37 @@ public class RequestResponseBodyMethodProcessor extends AbstractMessageConverter
 	public Object resolveArgument(MethodParameter parameter,
 								  ModelAndViewContainer mavContainer,
 								  NativeWebRequest webRequest,
-								  WebDataBinderFactory binderFactory)
-			throws IOException, HttpMediaTypeNotSupportedException {
-		return readWithMessageConverters(webRequest, parameter, parameter.getParameterType());
+								  WebDataBinderFactory binderFactory) throws Exception {
+		Object arg = readWithMessageConverters(webRequest, parameter, parameter.getParameterType());
+		if (shouldValidate(parameter, arg)) {
+			String argName = Conventions.getVariableNameForParameter(parameter);
+			WebDataBinder binder = binderFactory.createBinder(webRequest, arg, argName);
+			binder.validate();
+			Errors errors = binder.getBindingResult();
+			if (errors.hasErrors()) {
+				throw new RequestBodyNotValidException(errors);
+			}
+		}
+		return arg;
 	}
 
+	/**
+	 * Whether to validate the given @{@link RequestBody} method argument. The default implementation checks 
+	 * if the parameter is also annotated with {@code @Valid}.
+	 * @param parameter the method argument for which to check if validation is needed 
+	 * @param argumentValue the method argument value (instantiated with a message converter)
+	 * @return {@code true} if validation should be invoked, {@code false} otherwise.
+	 */
+	protected boolean shouldValidate(MethodParameter parameter, Object argumentValue) {
+		Annotation[] annotations = parameter.getParameterAnnotations();
+		for (Annotation annot : annotations) {
+			if ("Valid".equals(annot.annotationType().getSimpleName())) {
+				return true;
+			}
+		}
+		return false;
+	}
+	
 	public void handleReturnValue(Object returnValue,
 								  MethodParameter returnType,
 								  ModelAndViewContainer mavContainer,