AbstractJackson2HttpMessageConverter's canRead/canWrite checks media type first before delegating to Jackson

Issue: SPR-14163

Author: jhoeller

spring-web/src/main/java/org/springframework/http/converter/AbstractHttpMessageConverter.java

@@ -71,13 +71,20 @@ protected AbstractHttpMessageConverter(MediaType supportedMediaType) {
 	}
 
 	/**
-	 * Construct an {@code AbstractHttpMessageConverter} with multiple supported media type.
+	 * Construct an {@code AbstractHttpMessageConverter} with multiple supported media types.
 	 * @param supportedMediaTypes the supported media types
 	 */
 	protected AbstractHttpMessageConverter(MediaType... supportedMediaTypes) {
 		setSupportedMediaTypes(Arrays.asList(supportedMediaTypes));
 	}
 
+	/**
+	 * Construct an {@code AbstractHttpMessageConverter} with a default charset and
+	 * multiple supported media types.
+	 * @param defaultCharset the default character set
+	 * @param supportedMediaTypes the supported media types
+	 * @since 4.3
+	 */
 	protected AbstractHttpMessageConverter(Charset defaultCharset, MediaType... supportedMediaTypes) {
 		this.defaultCharset = defaultCharset;
 		setSupportedMediaTypes(Arrays.asList(supportedMediaTypes));
@@ -98,16 +105,22 @@ public List<MediaType> getSupportedMediaTypes() {
 	}
 
 	/**
-	 * Set the default character set if any.
+	 * Set the default character set, if any.
+	 * @since 4.3
 	 */
 	public void setDefaultCharset(Charset defaultCharset) {
 		this.defaultCharset = defaultCharset;
 	}
 
+	/**
+	 * Return the default character set, if any.
+	 * @since 4.3
+	 */
 	public Charset getDefaultCharset() {
-		return defaultCharset;
+		return this.defaultCharset;
 	}
 
+
 	/**
 	 * This implementation checks if the given class is {@linkplain #supports(Class) supported},
 	 * and if the {@linkplain #getSupportedMediaTypes() supported media types}
@@ -119,7 +132,7 @@ public boolean canRead(Class<?> clazz, MediaType mediaType) {
 	}
 
 	/**
-	 * Returns true if any of the {@linkplain #setSupportedMediaTypes(List)
+	 * Returns {@code true} if any of the {@linkplain #setSupportedMediaTypes(List)
 	 * supported} media types {@link MediaType#includes(MediaType) include} the
 	 * given media type.
 	 * @param mediaType the media type to read, can be {@code null} if not specified.

spring-web/src/main/java/org/springframework/http/converter/json/AbstractJackson2HttpMessageConverter.java

@@ -140,11 +140,14 @@ public boolean canRead(Class<?> clazz, MediaType mediaType) {
 	@Override
 	public boolean canRead(Type type, Class<?> contextClass, MediaType mediaType) {
 		JavaType javaType = getJavaType(type, contextClass);
+		if (!canRead(mediaType)) {
+			return false;
+		}
 		if (!logger.isWarnEnabled()) {
-			return (this.objectMapper.canDeserialize(javaType) && canRead(mediaType));
+			return this.objectMapper.canDeserialize(javaType);
 		}
 		AtomicReference<Throwable> causeRef = new AtomicReference<Throwable>();
-		if (this.objectMapper.canDeserialize(javaType, causeRef) && canRead(mediaType)) {
+		if (this.objectMapper.canDeserialize(javaType, causeRef)) {
 			return true;
 		}
 		Throwable cause = causeRef.get();
@@ -162,11 +165,14 @@ public boolean canRead(Type type, Class<?> contextClass, MediaType mediaType) {
 
 	@Override
 	public boolean canWrite(Class<?> clazz, MediaType mediaType) {
+		if (!canWrite(mediaType)) {
+			return false;
+		}
 		if (!logger.isWarnEnabled()) {
-			return (this.objectMapper.canSerialize(clazz) && canWrite(mediaType));
+			return this.objectMapper.canSerialize(clazz);
 		}
 		AtomicReference<Throwable> causeRef = new AtomicReference<Throwable>();
-		if (this.objectMapper.canSerialize(clazz, causeRef) && canWrite(mediaType)) {
+		if (this.objectMapper.canSerialize(clazz, causeRef)) {
 			return true;
 		}
 		Throwable cause = causeRef.get();