org.springframework.http.codec.HttpMessageWriter Java Examples

@Test
public void defaultWriters() {
	List<HttpMessageWriter<?>> writers = this.configurer.getWriters();
	assertEquals(11, writers.size());
	assertEquals(ByteArrayEncoder.class, getNextEncoder(writers).getClass());
	assertEquals(ByteBufferEncoder.class, getNextEncoder(writers).getClass());
	assertEquals(DataBufferEncoder.class, getNextEncoder(writers).getClass());
	assertEquals(ResourceHttpMessageWriter.class, writers.get(index.getAndIncrement()).getClass());
	assertStringEncoder(getNextEncoder(writers), true);
	assertEquals(MultipartHttpMessageWriter.class, writers.get(this.index.getAndIncrement()).getClass());
	assertEquals(ProtobufHttpMessageWriter.class, writers.get(index.getAndIncrement()).getClass());
	assertEquals(Jackson2JsonEncoder.class, getNextEncoder(writers).getClass());
	assertEquals(Jackson2SmileEncoder.class, getNextEncoder(writers).getClass());
	assertEquals(Jaxb2XmlEncoder.class, getNextEncoder(writers).getClass());
	assertStringEncoder(getNextEncoder(writers), false);
}
 

@Test
public void bodyParameterizedTypeReference() {
	String body = "foo";
	Publisher<String> publisher = Mono.just(body);
	ParameterizedTypeReference<String> typeReference = new ParameterizedTypeReference<String>() {};
	ClientRequest result = ClientRequest.create(POST, URI.create("http://example.com"))
			.body(publisher, typeReference).build();

	List<HttpMessageWriter<?>> messageWriters = new ArrayList<>();
	messageWriters.add(new EncoderHttpMessageWriter<>(CharSequenceEncoder.allMimeTypes()));

	ExchangeStrategies strategies = mock(ExchangeStrategies.class);
	when(strategies.messageWriters()).thenReturn(messageWriters);

	MockClientHttpRequest request = new MockClientHttpRequest(GET, "/");
	result.writeTo(request, strategies).block();
	assertNotNull(request.getBody());

	StepVerifier.create(request.getBody())
			.expectNextCount(1)
			.verifyComplete();
}
 

@Test
public void defaultWriters() {
	List<HttpMessageWriter<?>> writers = this.configurer.getWriters();
	assertEquals(11, writers.size());
	assertEquals(ByteArrayEncoder.class, getNextEncoder(writers).getClass());
	assertEquals(ByteBufferEncoder.class, getNextEncoder(writers).getClass());
	assertEquals(DataBufferEncoder.class, getNextEncoder(writers).getClass());
	assertEquals(ResourceHttpMessageWriter.class, writers.get(index.getAndIncrement()).getClass());
	assertStringEncoder(getNextEncoder(writers), true);
	assertEquals(ProtobufHttpMessageWriter.class, writers.get(index.getAndIncrement()).getClass());
	assertEquals(Jackson2JsonEncoder.class, getNextEncoder(writers).getClass());
	assertEquals(Jackson2SmileEncoder.class, getNextEncoder(writers).getClass());
	assertEquals(Jaxb2XmlEncoder.class, getNextEncoder(writers).getClass());
	assertSseWriter(writers);
	assertStringEncoder(getNextEncoder(writers), false);
}
 

/**
 * Return Object writers (JSON, XML, SSE).
 * @param forMultipart whether to returns writers for general use ("false"),
 * or for multipart requests only ("true"). Generally the two sets are the
 * same except for the multipart writer itself.
 */
final List<HttpMessageWriter<?>> getObjectWriters(boolean forMultipart) {
	if (!this.registerDefaults) {
		return Collections.emptyList();
	}
	List<HttpMessageWriter<?>> writers = new ArrayList<>();
	if (jackson2Present) {
		writers.add(new EncoderHttpMessageWriter<>(getJackson2JsonEncoder()));
	}
	if (jackson2SmilePresent) {
		writers.add(new EncoderHttpMessageWriter<>(new Jackson2SmileEncoder()));
	}
	if (jaxb2Present) {
		Encoder<?> encoder = this.jaxb2Encoder != null ? this.jaxb2Encoder : new Jaxb2XmlEncoder();
		writers.add(new EncoderHttpMessageWriter<>(encoder));
	}
	// No client or server specific multipart writers currently..
	if (!forMultipart) {
		extendObjectWriters(writers);
	}
	return writers;
}
 

/**
 * Return writers that support specific types.
 * @param forMultipart whether to returns writers for general use ("false"),
 * or for multipart requests only ("true"). Generally the two sets are the
 * same except for the multipart writer itself.
 */
@SuppressWarnings("unchecked")
final List<HttpMessageWriter<?>> getTypedWriters(boolean forMultipart) {
	if (!this.registerDefaults) {
		return Collections.emptyList();
	}
	List<HttpMessageWriter<?>> writers = new ArrayList<>();
	writers.add(new EncoderHttpMessageWriter<>(new ByteArrayEncoder()));
	writers.add(new EncoderHttpMessageWriter<>(new ByteBufferEncoder()));
	writers.add(new EncoderHttpMessageWriter<>(new DataBufferEncoder()));
	writers.add(new ResourceHttpMessageWriter());
	writers.add(new EncoderHttpMessageWriter<>(CharSequenceEncoder.textPlainOnly()));
	// No client or server specific multipart writers currently..
	if (!forMultipart) {
		extendTypedWriters(writers);
	}
	if (protobufPresent) {
		Encoder<?> encoder = this.protobufEncoder != null ? this.protobufEncoder : new ProtobufEncoder();
		writers.add(new ProtobufHttpMessageWriter((Encoder) encoder));
	}
	return writers;
}
 

@Override
protected Mono<Void> writeToInternal(ServerWebExchange exchange, Context context) {
	return this.inserter.insert(exchange.getResponse(), new BodyInserter.Context() {
		@Override
		public List<HttpMessageWriter<?>> messageWriters() {
			return context.messageWriters();
		}
		@Override
		public Optional<ServerHttpRequest> serverRequest() {
			return Optional.of(exchange.getRequest());
		}
		@Override
		public Map<String, Object> hints() {
			hints.put(Hints.LOG_PREFIX_HINT, exchange.getLogPrefix());
			return hints;
		}
	});
}
 

@Test
public void bodyClass() {
	String body = "foo";
	Publisher<String> publisher = Mono.just(body);
	ClientRequest result = ClientRequest.create(POST, URI.create("http://example.com"))
			.body(publisher, String.class).build();

	List<HttpMessageWriter<?>> messageWriters = new ArrayList<>();
	messageWriters.add(new EncoderHttpMessageWriter<>(CharSequenceEncoder.allMimeTypes()));

	ExchangeStrategies strategies = mock(ExchangeStrategies.class);
	when(strategies.messageWriters()).thenReturn(messageWriters);

	MockClientHttpRequest request = new MockClientHttpRequest(GET, "/");
	result.writeTo(request, strategies).block();
	assertNotNull(request.getBody());

	StepVerifier.create(request.getBody())
			.expectNextCount(1)
			.verifyComplete();
}
 

private AbstractMessageWriterResultHandler initResultHandler(HttpMessageWriter<?>... writers) {
	List<HttpMessageWriter<?>> writerList;
	if (ObjectUtils.isEmpty(writers)) {
		writerList = new ArrayList<>();
		writerList.add(new EncoderHttpMessageWriter<>(new ByteBufferEncoder()));
		writerList.add(new EncoderHttpMessageWriter<>(CharSequenceEncoder.allMimeTypes()));
		writerList.add(new ResourceHttpMessageWriter());
		writerList.add(new EncoderHttpMessageWriter<>(new Jaxb2XmlEncoder()));
		writerList.add(new EncoderHttpMessageWriter<>(new Jackson2JsonEncoder()));
	}
	else {
		writerList = Arrays.asList(writers);
	}
	RequestedContentTypeResolver resolver = new RequestedContentTypeResolverBuilder().build();
	return new AbstractMessageWriterResultHandler(writerList, resolver) {};
}
 

@Override
protected Mono<Void> writeToInternal(ServerWebExchange exchange, Context context) {
	return inserter().insert(exchange.getResponse(), new BodyInserter.Context() {
		@Override
		public List<HttpMessageWriter<?>> messageWriters() {
			return context.messageWriters();
		}
		@Override
		public Optional<ServerHttpRequest> serverRequest() {
			return Optional.of(exchange.getRequest());
		}
		@Override
		public Map<String, Object> hints() {
			hints.put(Hints.LOG_PREFIX_HINT, exchange.getLogPrefix());
			return hints;
		}
	});
}
 

private AbstractMessageWriterResultHandler initResultHandler(HttpMessageWriter<?>... writers) {
	List<HttpMessageWriter<?>> writerList;
	if (ObjectUtils.isEmpty(writers)) {
		writerList = new ArrayList<>();
		writerList.add(new EncoderHttpMessageWriter<>(new ByteBufferEncoder()));
		writerList.add(new EncoderHttpMessageWriter<>(CharSequenceEncoder.allMimeTypes()));
		writerList.add(new ResourceHttpMessageWriter());
		writerList.add(new EncoderHttpMessageWriter<>(new Jaxb2XmlEncoder()));
		writerList.add(new EncoderHttpMessageWriter<>(new Jackson2JsonEncoder()));
	}
	else {
		writerList = Arrays.asList(writers);
	}
	RequestedContentTypeResolver resolver = new RequestedContentTypeResolverBuilder().build();
	return new AbstractMessageWriterResultHandler(writerList, resolver) {};
}
 

@Test
public void defaultsOffWithCustomWriters() {
	Encoder<?> customEncoder1 = mock(Encoder.class);
	Encoder<?> customEncoder2 = mock(Encoder.class);

	given(customEncoder1.canEncode(ResolvableType.forClass(Object.class), null)).willReturn(false);
	given(customEncoder2.canEncode(ResolvableType.forClass(Object.class), null)).willReturn(true);

	HttpMessageWriter<?> customWriter1 = mock(HttpMessageWriter.class);
	HttpMessageWriter<?> customWriter2 = mock(HttpMessageWriter.class);

	given(customWriter1.canWrite(ResolvableType.forClass(Object.class), null)).willReturn(false);
	given(customWriter2.canWrite(ResolvableType.forClass(Object.class), null)).willReturn(true);

	this.configurer.customCodecs().encoder(customEncoder1);
	this.configurer.customCodecs().encoder(customEncoder2);

	this.configurer.customCodecs().writer(customWriter1);
	this.configurer.customCodecs().writer(customWriter2);

	this.configurer.registerDefaults(false);

	List<HttpMessageWriter<?>> writers = this.configurer.getWriters();

	assertEquals(4, writers.size());
	assertSame(customEncoder1, getNextEncoder(writers));
	assertSame(customWriter1, writers.get(this.index.getAndIncrement()));
	assertSame(customEncoder2, getNextEncoder(writers));
	assertSame(customWriter2, writers.get(this.index.getAndIncrement()));
}
 

@Test
public void bodyInserter() {
	String body = "foo";
	Publisher<String> publisher = Mono.just(body);

	Mono<EntityResponse<Publisher<String>>> result = EntityResponse.fromPublisher(publisher, String.class).build();

	MockServerWebExchange exchange = MockServerWebExchange.from(MockServerHttpRequest.get("http://localhost"));

	ServerResponse.Context context = new ServerResponse.Context() {
		@Override
		public List<HttpMessageWriter<?>> messageWriters() {
			return Collections.singletonList(new EncoderHttpMessageWriter<>(CharSequenceEncoder.allMimeTypes()));
		}

		@Override
		public List<ViewResolver> viewResolvers() {
			return Collections.emptyList();
		}
	};
	StepVerifier.create(result)
			.consumeNextWith(response -> {
				StepVerifier.create(response.entity())
						.expectNext(body)
						.expectComplete()
						.verify();
				response.writeTo(exchange, context);
			})
			.expectComplete()
			.verify();

	assertNotNull(exchange.getResponse().getBody());
}
 

@Before
public void beforeMethod() {
    generalUtils = ApiExceptionHandlerUtils.DEFAULT_IMPL;
    testProjectApiErrors = ProjectApiErrorsForTesting.withProjectSpecificData(null, null);
    springUtilsMock = mock(SpringWebfluxApiExceptionHandlerUtils.class);
    viewResolversProviderMock = mock(ObjectProvider.class);
    serverCodecConfigurerMock = mock(ServerCodecConfigurer.class);
    messageReaders = Arrays.asList(mock(HttpMessageReader.class), mock(HttpMessageReader.class));
    messageWriters = Arrays.asList(mock(HttpMessageWriter.class), mock(HttpMessageWriter.class));
    viewResolvers = Arrays.asList(mock(ViewResolver.class), mock(ViewResolver.class));
    serverWebExchangeMock = mock(ServerWebExchange.class);
    serverHttpRequestMock = mock(ServerHttpRequest.class);
    serverHttpResponseMock = mock(ServerHttpResponse.class);
    serverHttpResponseHeadersMock = mock(HttpHeaders.class);
    uri = URI.create("http://localhost:8080/foo/bar?someQuery=someValue");
    exMock = mock(Throwable.class);

    doAnswer(invocation -> viewResolvers.stream()).when(viewResolversProviderMock).orderedStream();
    doReturn(messageReaders).when(serverCodecConfigurerMock).getReaders();
    doReturn(messageWriters).when(serverCodecConfigurerMock).getWriters();

    doReturn(serverHttpRequestMock).when(serverWebExchangeMock).getRequest();
    doReturn(uri).when(serverHttpRequestMock).getURI();

    doReturn(serverHttpResponseMock).when(serverWebExchangeMock).getResponse();
    doReturn(serverHttpResponseHeadersMock).when(serverHttpResponseMock).getHeaders();

    handlerSpy = spy(new SpringWebfluxUnhandledExceptionHandler(
        testProjectApiErrors, generalUtils, springUtilsMock, viewResolversProviderMock, serverCodecConfigurerMock
    ));
}
 

private void assertSseWriter(List<HttpMessageWriter<?>> writers) {
	HttpMessageWriter<?> writer = writers.get(this.index.getAndIncrement());
	assertEquals(ServerSentEventHttpMessageWriter.class, writer.getClass());
	Encoder<?> encoder = ((ServerSentEventHttpMessageWriter) writer).getEncoder();
	assertNotNull(encoder);
	assertEquals(Jackson2JsonEncoder.class, encoder.getClass());
}
 

@Before
public void setup() throws Exception {
	List<HttpMessageReader<?>> readers = ServerCodecConfigurer.create().getReaders();
	ReactiveAdapterRegistry registry = ReactiveAdapterRegistry.getSharedInstance();
	this.resolver = new RequestPartMethodArgumentResolver(readers, registry);

	List<HttpMessageWriter<?>> writers = ClientCodecConfigurer.create().getWriters();
	this.writer = new MultipartHttpMessageWriter(writers);
}
 

protected ResponseContext(
    List<HttpMessageWriter<?>> messageWriters,
    List<ViewResolver> viewResolvers
) {
    this.messageWriters = messageWriters;
    this.viewResolvers = viewResolvers;
}
 

@Before
public void createContext() {
	final List<HttpMessageWriter<?>> messageWriters = new ArrayList<>();
	messageWriters.add(new EncoderHttpMessageWriter<>(new ByteBufferEncoder()));
	messageWriters.add(new EncoderHttpMessageWriter<>(CharSequenceEncoder.textPlainOnly()));
	messageWriters.add(new ResourceHttpMessageWriter());
	messageWriters.add(new EncoderHttpMessageWriter<>(new Jaxb2XmlEncoder()));
	Jackson2JsonEncoder jsonEncoder = new Jackson2JsonEncoder();
	messageWriters.add(new EncoderHttpMessageWriter<>(jsonEncoder));
	messageWriters.add(new ServerSentEventHttpMessageWriter(jsonEncoder));
	messageWriters.add(new FormHttpMessageWriter());
	messageWriters.add(new EncoderHttpMessageWriter<>(CharSequenceEncoder.allMimeTypes()));
	messageWriters.add(new MultipartHttpMessageWriter(messageWriters));

	this.context = new BodyInserter.Context() {
		@Override
		public List<HttpMessageWriter<?>> messageWriters() {
			return messageWriters;
		}
		@Override
		public Optional<ServerHttpRequest> serverRequest() {
			return Optional.empty();
		}
		@Override
		public Map<String, Object> hints() {
			return hints;
		}
	};
	this.hints = new HashMap<>();
}
 

@Test
public void responseEntityResultHandler() throws Exception {
	ApplicationContext context = loadConfig(WebFluxConfig.class);

	String name = "responseEntityResultHandler";
	ResponseEntityResultHandler handler = context.getBean(name, ResponseEntityResultHandler.class);
	assertNotNull(handler);

	assertEquals(0, handler.getOrder());

	List<HttpMessageWriter<?>> writers = handler.getMessageWriters();
	assertEquals(11, writers.size());

	assertHasMessageWriter(writers, forClass(byte[].class), APPLICATION_OCTET_STREAM);
	assertHasMessageWriter(writers, forClass(ByteBuffer.class), APPLICATION_OCTET_STREAM);
	assertHasMessageWriter(writers, forClass(String.class), TEXT_PLAIN);
	assertHasMessageWriter(writers, forClass(Resource.class), IMAGE_PNG);
	assertHasMessageWriter(writers, forClass(Message.class), new MediaType("application", "x-protobuf"));
	assertHasMessageWriter(writers, forClass(TestBean.class), APPLICATION_XML);
	assertHasMessageWriter(writers, forClass(TestBean.class), APPLICATION_JSON);
	assertHasMessageWriter(writers, forClass(TestBean.class), new MediaType("application", "x-jackson-smile"));
	assertHasMessageWriter(writers, forClass(TestBean.class), MediaType.parseMediaType("text/event-stream"));

	name = "webFluxContentTypeResolver";
	RequestedContentTypeResolver resolver = context.getBean(name, RequestedContentTypeResolver.class);
	assertSame(resolver, handler.getContentTypeResolver());
}
 

@Override
public Mono<Void> handleResult(ServerWebExchange exchange, HandlerResult result) {
	ServerResponse response = (ServerResponse) result.getReturnValue();
	Assert.state(response != null, "No ServerResponse");
	return response.writeTo(exchange, new ServerResponse.Context() {
		@Override
		public List<HttpMessageWriter<?>> messageWriters() {
			return messageWriters;
		}
		@Override
		public List<ViewResolver> viewResolvers() {
			return viewResolvers;
		}
	});
}
 

@Override
protected void extendTypedWriters(List<HttpMessageWriter<?>> typedWriters) {

	FormHttpMessageWriter formWriter = new FormHttpMessageWriter();
	formWriter.setEnableLoggingRequestDetails(isEnableLoggingRequestDetails());

	MultipartHttpMessageWriter multipartWriter = new MultipartHttpMessageWriter(getPartWriters(), formWriter);
	multipartWriter.setEnableLoggingRequestDetails(isEnableLoggingRequestDetails());

	typedWriters.add(multipartWriter);
}
 

@Test
public void defaultAndCustomWriters() {
	Encoder<?> customEncoder1 = mock(Encoder.class);
	Encoder<?> customEncoder2 = mock(Encoder.class);

	when(customEncoder1.canEncode(ResolvableType.forClass(Object.class), null)).thenReturn(false);
	when(customEncoder2.canEncode(ResolvableType.forClass(Object.class), null)).thenReturn(true);

	HttpMessageWriter<?> customWriter1 = mock(HttpMessageWriter.class);
	HttpMessageWriter<?> customWriter2 = mock(HttpMessageWriter.class);

	when(customWriter1.canWrite(ResolvableType.forClass(Object.class), null)).thenReturn(false);
	when(customWriter2.canWrite(ResolvableType.forClass(Object.class), null)).thenReturn(true);

	this.configurer.customCodecs().encoder(customEncoder1);
	this.configurer.customCodecs().encoder(customEncoder2);

	this.configurer.customCodecs().writer(customWriter1);
	this.configurer.customCodecs().writer(customWriter2);

	List<HttpMessageWriter<?>> writers = this.configurer.getWriters();

	assertEquals(14, writers.size());
	assertEquals(ByteArrayEncoder.class, getNextEncoder(writers).getClass());
	assertEquals(ByteBufferEncoder.class, getNextEncoder(writers).getClass());
	assertEquals(DataBufferEncoder.class, getNextEncoder(writers).getClass());
	assertEquals(ResourceHttpMessageWriter.class, writers.get(index.getAndIncrement()).getClass());
	assertEquals(CharSequenceEncoder.class, getNextEncoder(writers).getClass());
	assertEquals(ProtobufHttpMessageWriter.class, writers.get(index.getAndIncrement()).getClass());
	assertSame(customEncoder1, getNextEncoder(writers));
	assertSame(customWriter1, writers.get(this.index.getAndIncrement()));
	assertEquals(Jackson2JsonEncoder.class, getNextEncoder(writers).getClass());
	assertEquals(Jackson2SmileEncoder.class, getNextEncoder(writers).getClass());
	assertEquals(Jaxb2XmlEncoder.class, getNextEncoder(writers).getClass());
	assertSame(customEncoder2, getNextEncoder(writers));
	assertSame(customWriter2, writers.get(this.index.getAndIncrement()));
	assertEquals(CharSequenceEncoder.class, getNextEncoder(writers).getClass());
}
 

@Test
public void responseBodyResultHandler() throws Exception {
	ApplicationContext context = loadConfig(WebFluxConfig.class);

	String name = "responseBodyResultHandler";
	ResponseBodyResultHandler handler = context.getBean(name, ResponseBodyResultHandler.class);
	assertNotNull(handler);

	assertEquals(100, handler.getOrder());

	List<HttpMessageWriter<?>> writers = handler.getMessageWriters();
	assertEquals(11, writers.size());

	assertHasMessageWriter(writers, forClass(byte[].class), APPLICATION_OCTET_STREAM);
	assertHasMessageWriter(writers, forClass(ByteBuffer.class), APPLICATION_OCTET_STREAM);
	assertHasMessageWriter(writers, forClass(String.class), TEXT_PLAIN);
	assertHasMessageWriter(writers, forClass(Resource.class), IMAGE_PNG);
	assertHasMessageWriter(writers, forClass(Message.class), new MediaType("application", "x-protobuf"));
	assertHasMessageWriter(writers, forClass(TestBean.class), APPLICATION_XML);
	assertHasMessageWriter(writers, forClass(TestBean.class), APPLICATION_JSON);
	assertHasMessageWriter(writers, forClass(TestBean.class), new MediaType("application", "x-jackson-smile"));
	assertHasMessageWriter(writers, forClass(TestBean.class), null);

	name = "webFluxContentTypeResolver";
	RequestedContentTypeResolver resolver = context.getBean(name, RequestedContentTypeResolver.class);
	assertSame(resolver, handler.getContentTypeResolver());
}
 

private List<HttpMessageWriter<?>> getPartWriters() {
	if (this.multipartCodecs != null) {
		return this.multipartCodecs.getWriters();
	}
	else if (this.partWritersSupplier != null) {
		return this.partWritersSupplier.get();
	}
	else {
		return Collections.emptyList();
	}
}
 

@Test
public void responseEntityResultHandler() throws Exception {
	ApplicationContext context = loadConfig(WebFluxConfig.class);

	String name = "responseEntityResultHandler";
	ResponseEntityResultHandler handler = context.getBean(name, ResponseEntityResultHandler.class);
	assertNotNull(handler);

	assertEquals(0, handler.getOrder());

	List<HttpMessageWriter<?>> writers = handler.getMessageWriters();
	assertEquals(11, writers.size());

	assertHasMessageWriter(writers, forClass(byte[].class), APPLICATION_OCTET_STREAM);
	assertHasMessageWriter(writers, forClass(ByteBuffer.class), APPLICATION_OCTET_STREAM);
	assertHasMessageWriter(writers, forClass(String.class), TEXT_PLAIN);
	assertHasMessageWriter(writers, forClass(Resource.class), IMAGE_PNG);
	assertHasMessageWriter(writers, forClass(Message.class), new MediaType("application", "x-protobuf"));
	assertHasMessageWriter(writers, forClass(TestBean.class), APPLICATION_XML);
	assertHasMessageWriter(writers, forClass(TestBean.class), APPLICATION_JSON);
	assertHasMessageWriter(writers, forClass(TestBean.class), new MediaType("application", "x-jackson-smile"));
	assertHasMessageWriter(writers, forClass(TestBean.class), MediaType.parseMediaType("text/event-stream"));

	name = "webFluxContentTypeResolver";
	RequestedContentTypeResolver resolver = context.getBean(name, RequestedContentTypeResolver.class);
	assertSame(resolver, handler.getContentTypeResolver());
}
 

@SuppressWarnings("unchecked")
private <T> Mono<Void> write(T value, @Nullable MediaType contentType, ServerWebExchange exchange) {
	Publisher<T> input = Mono.justOrEmpty(value);
	ResolvableType elementType = ResolvableType.forClass(value.getClass());
	return ((HttpMessageWriter<T>) this.writer).write(
			input, elementType, contentType, exchange.getResponse(),
			Hints.from(Hints.LOG_PREFIX_HINT, exchange.getLogPrefix()));
}
 

@Before
public void createContext() {
	HandlerStrategies strategies = HandlerStrategies.withDefaults();
	context = new ServerResponse.Context() {
		@Override
		public List<HttpMessageWriter<?>> messageWriters() {
			return strategies.messageWriters();
		}
		@Override
		public List<ViewResolver> viewResolvers() {
			return strategies.viewResolvers();
		}
	};
}
 

/**
 * Constructor with an additional {@link ReactiveAdapterRegistry}.
 * @param messageWriters for serializing Objects to the response body stream
 * @param contentTypeResolver for resolving the requested content type
 * @param adapterRegistry for adapting other reactive types (e.g. rx.Observable,
 * rx.Single, etc.) to Flux or Mono
 */
protected AbstractMessageWriterResultHandler(List<HttpMessageWriter<?>> messageWriters,
		RequestedContentTypeResolver contentTypeResolver, ReactiveAdapterRegistry adapterRegistry) {

	super(contentTypeResolver, adapterRegistry);
	Assert.notEmpty(messageWriters, "At least one message writer is required");
	this.messageWriters = messageWriters;
}
 

@Override
public Mono<Void> insert(ClientHttpRequest outputMessage, Context context) {
	HttpMessageWriter<MultiValueMap<String, HttpEntity<?>>> messageWriter =
			findWriter(context, MULTIPART_DATA_TYPE, MediaType.MULTIPART_FORM_DATA);
	MultiValueMap<String, HttpEntity<?>> body = this.builder.build();
	return messageWriter.write(Mono.just(body), MULTIPART_DATA_TYPE,
			MediaType.MULTIPART_FORM_DATA, outputMessage, context.hints());
}
 

private List<MediaType> getMediaTypesFor(ResolvableType elementType) {
	List<MediaType> writableMediaTypes = new ArrayList<>();
	for (HttpMessageWriter<?> converter : getMessageWriters()) {
		if (converter.canWrite(elementType, null)) {
			writableMediaTypes.addAll(converter.getWritableMediaTypes());
		}
	}
	return writableMediaTypes;
}
 

@Before
public void setup() throws Exception {
	List<HttpMessageWriter<?>> writerList = new ArrayList<>(5);
	writerList.add(new EncoderHttpMessageWriter<>(new ByteBufferEncoder()));
	writerList.add(new EncoderHttpMessageWriter<>(CharSequenceEncoder.allMimeTypes()));
	writerList.add(new ResourceHttpMessageWriter());
	writerList.add(new EncoderHttpMessageWriter<>(new Jaxb2XmlEncoder()));
	writerList.add(new EncoderHttpMessageWriter<>(new Jackson2JsonEncoder()));
	RequestedContentTypeResolver resolver = new RequestedContentTypeResolverBuilder().build();
	this.resultHandler = new ResponseBodyResultHandler(writerList, resolver);
}