FormHttpMessageConverter's charset (and its UTF-8 default) applies to part converters as well

Issue: SPR-14338

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

@@ -43,6 +43,7 @@ import org.springframework.util.Assert;
  *
  * @author Arjen Poutsma
  * @author Juergen Hoeller
+ * @author Sebastien Deleuze
  * @since 3.0
  */
 public abstract class AbstractHttpMessageConverter<T> implements HttpMessageConverter<T> {
@@ -246,8 +247,11 @@ public abstract class AbstractHttpMessageConverter<T> implements HttpMessageConv
 				contentTypeToUse = (mediaType != null ? mediaType : contentTypeToUse);
 			}
 			if (contentTypeToUse != null) {
-				if (contentTypeToUse.getCharset() == null && this.defaultCharset != null) {
-					contentTypeToUse = new MediaType(contentTypeToUse, this.defaultCharset);
+				if (contentTypeToUse.getCharset() == null) {
+					Charset defaultCharset = getDefaultCharset();
+					if (defaultCharset != null) {
+						contentTypeToUse = new MediaType(contentTypeToUse, defaultCharset);
+					}
 				}
 				headers.setContentType(contentTypeToUse);
 			}

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -32,15 +32,19 @@ import org.springframework.util.StreamUtils;
  * overridden by setting the {@link #setSupportedMediaTypes supportedMediaTypes} property.
  *
  * @author Arjen Poutsma
+ * @author Juergen Hoeller
  * @since 3.0
  */
 public class ByteArrayHttpMessageConverter extends AbstractHttpMessageConverter<byte[]> {
 
-	/** Creates a new instance of the {@code ByteArrayHttpMessageConverter}. */
+	/**
+	 * Create a new instance of the {@code ByteArrayHttpMessageConverter}.
+	 */
 	public ByteArrayHttpMessageConverter() {
 		super(new MediaType("application", "octet-stream"), MediaType.ALL);
 	}
 
+
 	@Override
 	public boolean supports(Class<?> clazz) {
 		return byte[].class == clazz;

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -82,6 +82,7 @@ import org.springframework.util.StringUtils;
  *
  * @author Arjen Poutsma
  * @author Rossen Stoyanchev
+ * @author Juergen Hoeller
  * @since 3.0
  * @see MultiValueMap
  */
@@ -90,14 +91,14 @@ public class FormHttpMessageConverter implements HttpMessageConverter<MultiValue
 	public static final Charset DEFAULT_CHARSET = Charset.forName("UTF-8");
 
 
-	private Charset charset = DEFAULT_CHARSET;
-
-	private Charset multipartCharset;
-
 	private List<MediaType> supportedMediaTypes = new ArrayList<MediaType>();
 
 	private List<HttpMessageConverter<?>> partConverters = new ArrayList<HttpMessageConverter<?>>();
 
+	private Charset charset = DEFAULT_CHARSET;
+
+	private Charset multipartCharset;
+
 
 	public FormHttpMessageConverter() {
 		this.supportedMediaTypes.add(MediaType.APPLICATION_FORM_URLENCODED);
@@ -108,30 +109,10 @@ public class FormHttpMessageConverter implements HttpMessageConverter<MultiValue
 		stringHttpMessageConverter.setWriteAcceptCharset(false);
 		this.partConverters.add(stringHttpMessageConverter);
 		this.partConverters.add(new ResourceHttpMessageConverter());
-	}
 
-
-	/**
-	 * Set the default character set to use for reading and writing form data when
-	 * the request or response Content-Type header does not explicitly specify it.
-	 * <p>By default this is set to "UTF-8".
-	 */
-	public void setCharset(Charset charset) {
-		this.charset = charset;
+		applyDefaultCharset();
 	}
 
-	/**
-	 * Set the character set to use when writing multipart data to encode file
-	 * names. Encoding is based on the encoded-word syntax defined in RFC 2047
-	 * and relies on {@code MimeUtility} from "javax.mail".
-	 * <p>If not set file names will be encoded as US-ASCII.
-	 * @param multipartCharset the charset to use
-	 * @since 4.1.1
-	 * @see <a href="http://en.wikipedia.org/wiki/MIME#Encoded-Word">Encoded-Word</a>
-	 */
-	public void setMultipartCharset(Charset multipartCharset) {
-		this.multipartCharset = multipartCharset;
-	}
 
 	/**
 	 * Set the list of {@link MediaType} objects supported by this converter.
@@ -163,6 +144,49 @@ public class FormHttpMessageConverter implements HttpMessageConverter<MultiValue
 		this.partConverters.add(partConverter);
 	}
 
+	/**
+	 * Set the default character set to use for reading and writing form data when
+	 * the request or response Content-Type header does not explicitly specify it.
+	 * <p>By default this is set to "UTF-8". As of 4.3, it will also be used as
+	 * the default charset for the conversion of text bodies in a multipart request.
+	 * In contrast to this, {@link #setMultipartCharset} only affects the encoding of
+	 * <i>file names</i> in a multipart request according to the encoded-word syntax.
+	 */
+	public void setCharset(Charset charset) {
+		if (charset != this.charset) {
+			this.charset = (charset != null ? charset : DEFAULT_CHARSET);
+			applyDefaultCharset();
+		}
+	}
+
+	/**
+	 * Apply the configured charset as a default to registered part converters.
+	 */
+	private void applyDefaultCharset() {
+		for (HttpMessageConverter<?> candidate : this.partConverters) {
+			if (candidate instanceof AbstractHttpMessageConverter) {
+				AbstractHttpMessageConverter<?> converter = (AbstractHttpMessageConverter<?>) candidate;
+				// Only override default charset if the converter operates with a charset to begin with...
+				if (converter.getDefaultCharset() != null) {
+					converter.setDefaultCharset(this.charset);
+				}
+			}
+		}
+	}
+
+	/**
+	 * Set the character set to use when writing multipart data to encode file
+	 * names. Encoding is based on the encoded-word syntax defined in RFC 2047
+	 * and relies on {@code MimeUtility} from "javax.mail".
+	 * <p>If not set file names will be encoded as US-ASCII.
+	 * @param multipartCharset the charset to use
+	 * @since 4.1.1
+	 * @see <a href="http://en.wikipedia.org/wiki/MIME#Encoded-Word">Encoded-Word</a>
+	 */
+	public void setMultipartCharset(Charset multipartCharset) {
+		this.multipartCharset = multipartCharset;
+	}
+
 
 	@Override
 	public boolean canRead(Class<?> clazz, MediaType mediaType) {
@@ -255,7 +279,7 @@ public class FormHttpMessageConverter implements HttpMessageConverter<MultiValue
 		Charset charset;
 		if (contentType != null) {
 			outputMessage.getHeaders().setContentType(contentType);
-			charset = contentType.getCharset() != null ? contentType.getCharset() : this.charset;
+			charset = (contentType.getCharset() != null ? contentType.getCharset() : this.charset);
 		}
 		else {
 			outputMessage.getHeaders().setContentType(MediaType.APPLICATION_FORM_URLENCODED);

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -29,8 +29,8 @@ import org.springframework.util.Assert;
  * An {@code HttpMessageConverter} that uses {@link StringHttpMessageConverter}
  * for reading and writing content and a {@link ConversionService} for converting
  * the String content to and from the target object type.
- * <p>
- * By default, this converter supports the media type {@code text/plain} only.
+ *
+ * <p>By default, this converter supports the media type {@code text/plain} only.
  * This can be overridden by setting the
  * {@link #setSupportedMediaTypes supportedMediaTypes} property.
  * Example of usage:
@@ -49,17 +49,15 @@ import org.springframework.util.Assert;
  */
 public class ObjectToStringHttpMessageConverter extends AbstractHttpMessageConverter<Object> {
 
-	private ConversionService conversionService;
+	private final ConversionService conversionService;
 
-	private StringHttpMessageConverter stringHttpMessageConverter;
+	private final StringHttpMessageConverter stringHttpMessageConverter;
 
 
 	/**
 	 * A constructor accepting a {@code ConversionService} to use to convert the
-	 * (String) message body to/from the target class type. This constructor
-	 * uses {@link StringHttpMessageConverter#DEFAULT_CHARSET} as the default
-	 * charset.
-	 *
+	 * (String) message body to/from the target class type. This constructor uses
+	 * {@link StringHttpMessageConverter#DEFAULT_CHARSET} as the default charset.
 	 * @param conversionService the conversion service
 	 */
 	public ObjectToStringHttpMessageConverter(ConversionService conversionService) {
@@ -67,9 +65,7 @@ public class ObjectToStringHttpMessageConverter extends AbstractHttpMessageConve
 	}
 
 	/**
-	 * A constructor accepting a {@code ConversionService} as well as a default
-	 * charset.
-	 *
+	 * A constructor accepting a {@code ConversionService} as well as a default charset.
 	 * @param conversionService the conversion service
 	 * @param defaultCharset the default charset
 	 */
@@ -81,6 +77,7 @@ public class ObjectToStringHttpMessageConverter extends AbstractHttpMessageConve
 		this.stringHttpMessageConverter = new StringHttpMessageConverter(defaultCharset);
 	}
 
+
 	/**
 	 * Indicates whether the {@code Accept-Charset} should be written to any outgoing request.
 	 * <p>Default is {@code true}.
@@ -89,6 +86,7 @@ public class ObjectToStringHttpMessageConverter extends AbstractHttpMessageConve
 		this.stringHttpMessageConverter.setWriteAcceptCharset(writeAcceptCharset);
 	}
 
+
 	@Override
 	public boolean canRead(Class<?> clazz, MediaType mediaType) {
 		return this.conversionService.canConvert(String.class, clazz) && canRead(mediaType);
@@ -113,8 +111,8 @@ public class ObjectToStringHttpMessageConverter extends AbstractHttpMessageConve
 
 	@Override
 	protected void writeInternal(Object obj, HttpOutputMessage outputMessage) throws IOException {
-		String s = this.conversionService.convert(obj, String.class);
-		this.stringHttpMessageConverter.writeInternal(s, outputMessage);
+		String value = this.conversionService.convert(obj, String.class);
+		this.stringHttpMessageConverter.writeInternal(value, outputMessage);
 	}
 
 	@Override

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -35,6 +35,7 @@ import org.springframework.util.StreamUtils;
  * by setting the {@link #setSupportedMediaTypes supportedMediaTypes} property.
  *
  * @author Arjen Poutsma
+ * @author Juergen Hoeller
  * @since 3.0
  */
 public class StringHttpMessageConverter extends AbstractHttpMessageConverter<String> {
@@ -122,7 +123,7 @@ public class StringHttpMessageConverter extends AbstractHttpMessageConverter<Str
 			return contentType.getCharset();
 		}
 		else {
-			return this.getDefaultCharset();
+			return getDefaultCharset();
 		}
 	}