SPR-6976 - Add debug log for HttpMessageConverter usage

org.springframework.web.servlet/src/main/java/org/springframework/web/servlet/mvc/annotation/AnnotationMethodHandlerAdapter.java

@@ -860,6 +860,14 @@ public class AnnotationMethodHandlerAdapter extends WebContentGenerator
 					for (HttpMessageConverter messageConverter : getMessageConverters()) {
 						if (messageConverter.canWrite(returnValueType, acceptedMediaType)) {
 							messageConverter.write(returnValue, acceptedMediaType, outputMessage);
+							if (logger.isDebugEnabled()) {
+								MediaType contentType = outputMessage.getHeaders().getContentType();
+								if (contentType == null) {
+									contentType = acceptedMediaType;
+								}
+								logger.debug("Written [" + returnValue + "] as \"" + contentType +
+										"\" using [" + messageConverter + "]");
+							}
 							this.responseArgumentUsed = true;
 							return;
 						}

org.springframework.web/src/main/java/org/springframework/web/bind/annotation/support/HandlerMethodInvoker.java

@@ -549,6 +549,10 @@ public class HandlerMethodInvoker {
 			for (HttpMessageConverter<?> messageConverter : this.messageConverters) {
 				allSupportedMediaTypes.addAll(messageConverter.getSupportedMediaTypes());
 				if (messageConverter.canRead(paramType, contentType)) {
+					if (logger.isDebugEnabled()) {
+						logger.debug("Reading [" + paramType.getName() + "] as \"" + contentType
+								+"\" using [" + messageConverter + "]");
+					}
 					return messageConverter.read(paramType, inputMessage);
 				}
 			}

org.springframework.web/src/main/java/org/springframework/web/client/HttpMessageConverterExtractor.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2009 the original author or authors.
+ * Copyright 2002-2010 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.
@@ -19,6 +19,9 @@ package org.springframework.web.client;
 import java.io.IOException;
 import java.util.List;
 
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
 import org.springframework.http.MediaType;
 import org.springframework.http.client.ClientHttpResponse;
 import org.springframework.http.converter.HttpMessageConverter;
@@ -38,15 +41,22 @@ public class HttpMessageConverterExtractor<T> implements ResponseExtractor<T> {
 
 	private final List<HttpMessageConverter<?>> messageConverters;
 
+	private final Log logger;
+
 	/**
 	 * Creates a new instance of the {@code HttpMessageConverterExtractor} with the given response type and message
 	 * converters. The given converters must support the response type.
 	 */
 	public HttpMessageConverterExtractor(Class<T> responseType, List<HttpMessageConverter<?>> messageConverters) {
+		this(responseType, messageConverters, LogFactory.getLog(HttpMessageConverterExtractor.class));
+	}
+
+	HttpMessageConverterExtractor(Class<T> responseType, List<HttpMessageConverter<?>> messageConverters, Log logger) {
 		Assert.notNull(responseType, "'responseType' must not be null");
 		Assert.notEmpty(messageConverters, "'messageConverters' must not be empty");
 		this.responseType = responseType;
 		this.messageConverters = messageConverters;
+		this.logger = logger;
 	}
 
 	@SuppressWarnings("unchecked")
@@ -57,6 +67,10 @@ public class HttpMessageConverterExtractor<T> implements ResponseExtractor<T> {
 		}
 		for (HttpMessageConverter messageConverter : messageConverters) {
 			if (messageConverter.canRead(responseType, contentType)) {
+				if (logger.isDebugEnabled()) {
+					logger.debug("Reading [" + responseType.getName() + "] as \"" + contentType
+							+"\" using [" + messageConverter + "]");
+				}
 				return (T) messageConverter.read(this.responseType, response);
 			}
 		}

org.springframework.web/src/main/java/org/springframework/web/client/RestTemplate.java

@@ -188,21 +188,21 @@ public class RestTemplate extends HttpAccessor implements RestOperations {
 	public <T> T getForObject(String url, Class<T> responseType, Object... urlVariables) throws RestClientException {
 		AcceptHeaderRequestCallback requestCallback = new AcceptHeaderRequestCallback(responseType);
 		HttpMessageConverterExtractor<T> responseExtractor =
-				new HttpMessageConverterExtractor<T>(responseType, getMessageConverters());
+				new HttpMessageConverterExtractor<T>(responseType, getMessageConverters(), logger);
 		return execute(url, HttpMethod.GET, requestCallback, responseExtractor, urlVariables);
 	}
 
 	public <T> T getForObject(String url, Class<T> responseType, Map<String, ?> urlVariables) throws RestClientException {
 		AcceptHeaderRequestCallback requestCallback = new AcceptHeaderRequestCallback(responseType);
 		HttpMessageConverterExtractor<T> responseExtractor =
-				new HttpMessageConverterExtractor<T>(responseType, getMessageConverters());
+				new HttpMessageConverterExtractor<T>(responseType, getMessageConverters(), logger);
 		return execute(url, HttpMethod.GET, requestCallback, responseExtractor, urlVariables);
 	}
 
 	public <T> T getForObject(URI url, Class<T> responseType) throws RestClientException {
 		AcceptHeaderRequestCallback requestCallback = new AcceptHeaderRequestCallback(responseType);
 		HttpMessageConverterExtractor<T> responseExtractor =
-				new HttpMessageConverterExtractor<T>(responseType, getMessageConverters());
+				new HttpMessageConverterExtractor<T>(responseType, getMessageConverters(), logger);
 		return execute(url, HttpMethod.GET, requestCallback, responseExtractor);
 	}
 
@@ -268,7 +268,7 @@ public class RestTemplate extends HttpAccessor implements RestOperations {
 			throws RestClientException {
 		HttpEntityRequestCallback requestCallback = new HttpEntityRequestCallback(request, responseType);
 		HttpMessageConverterExtractor<T> responseExtractor =
-				new HttpMessageConverterExtractor<T>(responseType, getMessageConverters());
+				new HttpMessageConverterExtractor<T>(responseType, getMessageConverters(), logger);
 		return execute(url, HttpMethod.POST, requestCallback, responseExtractor, uriVariables);
 	}
 
@@ -276,7 +276,7 @@ public class RestTemplate extends HttpAccessor implements RestOperations {
 			throws RestClientException {
 		HttpEntityRequestCallback requestCallback = new HttpEntityRequestCallback(request, responseType);
 		HttpMessageConverterExtractor<T> responseExtractor =
-				new HttpMessageConverterExtractor<T>(responseType, getMessageConverters());
+				new HttpMessageConverterExtractor<T>(responseType, getMessageConverters(), logger);
 		return execute(url, HttpMethod.POST, requestCallback, responseExtractor, uriVariables);
 	}
 
@@ -509,6 +509,9 @@ public class RestTemplate extends HttpAccessor implements RestOperations {
 				}
 				if (!allSupportedMediaTypes.isEmpty()) {
 					MediaType.sortBySpecificity(allSupportedMediaTypes);
+					if (logger.isDebugEnabled()) {
+						logger.debug("Setting request Accept header to " + allSupportedMediaTypes);
+					}
 					request.getHeaders().setAccept(allSupportedMediaTypes);
 				}
 			}
@@ -565,6 +568,16 @@ public class RestTemplate extends HttpAccessor implements RestOperations {
 						if (!requestHeaders.isEmpty()) {
 							httpRequest.getHeaders().putAll(requestHeaders);
 						}
+						if (logger.isDebugEnabled()) {
+							if (requestContentType != null) {
+								logger.debug("Writing [" + requestBody + "] as \"" + requestContentType + 
+										"\" using [" + messageConverter + "]");
+							}
+							else {
+								logger.debug("Writing [" + requestBody + "] using [" + messageConverter + "]");
+							}
+
+						}
 						messageConverter.write(requestBody, requestContentType, httpRequest);
 						return;
 					}
@@ -588,7 +601,7 @@ public class RestTemplate extends HttpAccessor implements RestOperations {
 
 		public HttpEntityResponseExtractor(Class<T> responseType) {
 			if (responseType != null) {
-				this.delegate = new HttpMessageConverterExtractor<T>(responseType, getMessageConverters());
+				this.delegate = new HttpMessageConverterExtractor<T>(responseType, getMessageConverters(), logger);
 			} else {
 				this.delegate = null;
 			}

org.springframework.web/src/test/java/org/springframework/web/client/RestTemplateIntegrationTests.java

@@ -192,6 +192,7 @@ public class RestTemplateIntegrationTests {
 	public void exchangePost() throws Exception {
 		HttpHeaders requestHeaders = new HttpHeaders();
 		requestHeaders.set("MyHeader", "MyValue");
+		requestHeaders.setContentType(MediaType.TEXT_PLAIN);
 		HttpEntity<String> requestEntity = new HttpEntity<String>(helloWorld, requestHeaders);
 		HttpEntity<?> result = template.exchange(URI + "/{method}", HttpMethod.POST, requestEntity, null, "post");
 		assertEquals("Invalid location", new URI(URI + "/post/1"), result.getHeaders().getLocation());