org.springframework.http.codec.multipart

Class MultipartHttpMessageWriter

java.lang.Object

org.springframework.http.codec.multipart.MultipartHttpMessageWriter

All Implemented Interfaces:

HttpMessageWriter<MultiValueMap<java.lang.String,?>>

public class MultipartHttpMessageWriter
extends java.lang.Object
implements HttpMessageWriter<MultiValueMap<java.lang.String,?>>

HttpMessageWriter for writing a MultiValueMap<String, ?> as multipart form data, i.e. "multipart/form-data", to the body of a request.

The serialization of individual parts is delegated to other writers. By default only String and Resource parts are supported but you can configure others through a constructor argument.

This writer can be configured with a FormHttpMessageWriter to delegate to. It is the preferred way of supporting both form data and multipart data (as opposed to registering each writer separately) so that when the MediaType is not specified and generics are not present on the target element type, we can inspect the values in the actual map and decide whether to write plain form data (String values only) or otherwise.

Since:

5.0

Author:

Sebastien Deleuze, Rossen Stoyanchev

See Also:

FormHttpMessageWriter

Field Summary

Fields

Modifier and Type	Field and Description
static java.nio.charset.Charset	DEFAULT_CHARSET

Constructor Summary

Constructors

Constructor and Description
MultipartHttpMessageWriter() Constructor with a default list of part writers (String and Resource).
MultipartHttpMessageWriter(java.util.List<HttpMessageWriter<?>> partWriters) Constructor with explicit list of writers for serializing parts.
MultipartHttpMessageWriter(java.util.List<HttpMessageWriter<?>> partWriters, HttpMessageWriter<MultiValueMap<java.lang.String,java.lang.String>> formWriter) Constructor with explicit list of writers for serializing parts and a writer for plain form data to fall back when no media type is specified and the actual map consists of String values only.

Method Summary

Modifier and Type	Method and Description
boolean	canWrite(ResolvableType elementType, MediaType mediaType) Whether the given object type is supported by this writer.
protected byte[]	generateMultipartBoundary() Generate a multipart boundary.
java.nio.charset.Charset	getCharset() Return the configured charset for part headers.
java.util.List<MediaType>	getWritableMediaTypes() Return the MediaType's that this writer supports.
void	setCharset(java.nio.charset.Charset charset) Set the character set to use for part headers such as "Content-Disposition" (and its filename parameter).
reactor.core.publisher.Mono<java.lang.Void>	write(org.reactivestreams.Publisher<? extends MultiValueMap<java.lang.String,?>> inputStream, ResolvableType elementType, MediaType mediaType, ReactiveHttpOutputMessage outputMessage, java.util.Map<java.lang.String,java.lang.Object> hints) Write an given stream of object to the output message.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.springframework.http.codec.HttpMessageWriter

write

Field Detail

DEFAULT_CHARSET

public static final java.nio.charset.Charset DEFAULT_CHARSET

Constructor Detail

MultipartHttpMessageWriter

public MultipartHttpMessageWriter()

Constructor with a default list of part writers (String and Resource).

MultipartHttpMessageWriter

public MultipartHttpMessageWriter(java.util.List<HttpMessageWriter<?>> partWriters)

Constructor with explicit list of writers for serializing parts.

MultipartHttpMessageWriter

public MultipartHttpMessageWriter(java.util.List<HttpMessageWriter<?>> partWriters,
                                  @Nullable
                                  HttpMessageWriter<MultiValueMap<java.lang.String,java.lang.String>> formWriter)

Constructor with explicit list of writers for serializing parts and a writer for plain form data to fall back when no media type is specified and the actual map consists of String values only.

Parameters:

partWriters - the writers for serializing parts

formWriter - the fallback writer for form data, null by default

Method Detail

setCharset

public void setCharset(java.nio.charset.Charset charset)

Set the character set to use for part headers such as "Content-Disposition" (and its filename parameter).

By default this is set to "UTF-8".

getCharset

public java.nio.charset.Charset getCharset()

Return the configured charset for part headers.

getWritableMediaTypes

public java.util.List<MediaType> getWritableMediaTypes()

Description copied from interface: HttpMessageWriter

Return the MediaType's that this writer supports.

Specified by:

getWritableMediaTypes in interface HttpMessageWriter<MultiValueMap<java.lang.String,?>>

canWrite

public boolean canWrite(ResolvableType elementType,
                        @Nullable
                        MediaType mediaType)

Description copied from interface: HttpMessageWriter

Whether the given object type is supported by this writer.

Specified by:

canWrite in interface HttpMessageWriter<MultiValueMap<java.lang.String,?>>

Parameters:

elementType - the type of object to check

mediaType - the media type for the write, possibly null

Returns:

true if writable, false otherwise

write

public reactor.core.publisher.Mono<java.lang.Void> write(org.reactivestreams.Publisher<? extends MultiValueMap<java.lang.String,?>> inputStream,
                                                         ResolvableType elementType,
                                                         @Nullable
                                                         MediaType mediaType,
                                                         ReactiveHttpOutputMessage outputMessage,
                                                         java.util.Map<java.lang.String,java.lang.Object> hints)

Description copied from interface: HttpMessageWriter

Write an given stream of object to the output message.

Specified by:

write in interface HttpMessageWriter<MultiValueMap<java.lang.String,?>>

Parameters:

inputStream - the objects to write

elementType - the type of objects in the stream which must have been previously checked via HttpMessageWriter.canWrite(ResolvableType, MediaType)

mediaType - the content type for the write, possibly null to indicate that the default content type of the writer must be used.

outputMessage - the message to write to

hints - additional information about how to encode and write

Returns:

indicates completion or error

generateMultipartBoundary

protected byte[] generateMultipartBoundary()

Generate a multipart boundary.

By default delegates to MimeTypeUtils.generateMultipartBoundary().