org.springframework.http.converter.HttpMessageConverter#read ( )源码实例Demo

@SuppressWarnings("unchecked")
private <T> T bodyInternal(Type bodyType, Class<?> bodyClass)
		throws ServletException, IOException {

	MediaType contentType =
			this.headers.contentType().orElse(MediaType.APPLICATION_OCTET_STREAM);

	for (HttpMessageConverter<?> messageConverter : this.messageConverters) {
		if (messageConverter instanceof GenericHttpMessageConverter) {
			GenericHttpMessageConverter<T> genericMessageConverter =
					(GenericHttpMessageConverter<T>) messageConverter;
			if (genericMessageConverter.canRead(bodyType, bodyClass, contentType)) {
				return genericMessageConverter.read(bodyType, bodyClass, this.serverHttpRequest);
			}
		}
		if (messageConverter.canRead(bodyClass, contentType)) {
			HttpMessageConverter<T> theConverter =
					(HttpMessageConverter<T>) messageConverter;
			Class<? extends T> clazz = (Class<? extends T>) bodyClass;
			return theConverter.read(clazz, this.serverHttpRequest);
		}
	}
	throw new HttpMediaTypeNotSupportedException(contentType, this.allSupportedMediaTypes);
}
 

@SuppressWarnings("unchecked")
private <T> T bodyInternal(Type bodyType, Class<?> bodyClass)
		throws ServletException, IOException {

	HttpInputMessage inputMessage = new BuiltInputMessage();
	MediaType contentType = headers().contentType().orElse(MediaType.APPLICATION_OCTET_STREAM);

	for (HttpMessageConverter<?> messageConverter : this.messageConverters) {
		if (messageConverter instanceof GenericHttpMessageConverter) {
			GenericHttpMessageConverter<T> genericMessageConverter =
					(GenericHttpMessageConverter<T>) messageConverter;
			if (genericMessageConverter.canRead(bodyType, bodyClass, contentType)) {
				return genericMessageConverter.read(bodyType, bodyClass, inputMessage);
			}
		}
		if (messageConverter.canRead(bodyClass, contentType)) {
			HttpMessageConverter<T> theConverter =
					(HttpMessageConverter<T>) messageConverter;
			Class<? extends T> clazz = (Class<? extends T>) bodyClass;
			return theConverter.read(clazz, inputMessage);
		}
	}
	throw new HttpMediaTypeNotSupportedException(contentType, Collections.emptyList());
}
 

@Override
public T extractData(ResponseEntity<HttpInputMessage> responseEntity) throws IOException {
    MediaType contentType = getContentType(responseEntity);
    for (HttpMessageConverter<?> messageConverter : this.messageConverters) {
        if (messageConverter instanceof GenericHttpMessageConverter) {
            GenericHttpMessageConverter<?> genericMessageConverter =
                    (GenericHttpMessageConverter<?>) messageConverter;
            if (genericMessageConverter.canRead(this.responseType, null, contentType)) {
                return (T) genericMessageConverter.read(this.responseType, null, responseEntity.getBody());
            }
        }
        if (this.responseClass != null) {
            if (messageConverter.canRead(this.responseClass, contentType)) {
                return (T) messageConverter.read((Class) this.responseClass, responseEntity.getBody());
            }
        }
    }

    throw new WxApiResponseException("不能转换相应数据为类型：" + this.responseType, responseEntity);
}
 

@SuppressWarnings({ "rawtypes", "unchecked" })
@Override
public void handleError(ClientHttpResponse response) throws IOException {
    MediaType mediaType = response.getHeaders().getContentType();
    RestError error = null;
    for(HttpMessageConverter converter : converters) {
        if(converter.canRead(JaxbRestError.class, mediaType)) {
            try {
                error = (RestError)converter.read(JaxbRestError.class, response);
            } catch(Exception e) {
                error = new JaxbRestError();
                ((JaxbRestError)error).setStatus(response.getRawStatusCode());
            }
            break;
        }
    }
    throw new DCTMRestErrorException(response.getHeaders(), response.getStatusCode(), error);
}
 

@Override
public Object resolve(RestMethodMetadata restMethodMetadata,
		MethodParameterMetadata methodParameterMetadata, HttpServerRequest request) {

	if (!supportParameter(restMethodMetadata, methodParameterMetadata)) {
		return null;
	}

	Object result = null;

	Class<?> parameterType = resolveClass(methodParameterMetadata.getType());

	HttpMessageConverterHolder holder = httpMessageConverterResolver.resolve(request,
			parameterType);

	if (holder != null) {
		HttpMessageConverter converter = holder.getConverter();
		try {
			result = converter.read(parameterType, request);
		}
		catch (IOException e) {
			throw new HttpMessageNotReadableException(
					"I/O error while reading input message", e);
		}
	}

	return result;
}
 

@Override
@SuppressWarnings({"unchecked", "rawtypes", "resource"})
public T extractData(ClientHttpResponse response) throws IOException {
	MessageBodyClientHttpResponseWrapper responseWrapper = new MessageBodyClientHttpResponseWrapper(response);
	if (!responseWrapper.hasMessageBody() || responseWrapper.hasEmptyMessageBody()) {
		return null;
	}
	MediaType contentType = getContentType(responseWrapper);

	for (HttpMessageConverter<?> messageConverter : this.messageConverters) {
		if (messageConverter instanceof GenericHttpMessageConverter) {
			GenericHttpMessageConverter<?> genericMessageConverter =
					(GenericHttpMessageConverter<?>) messageConverter;
			if (genericMessageConverter.canRead(this.responseType, null, contentType)) {
				if (logger.isDebugEnabled()) {
					logger.debug("Reading [" + this.responseType + "] as \"" +
							contentType + "\" using [" + messageConverter + "]");
				}
				return (T) genericMessageConverter.read(this.responseType, null, responseWrapper);
			}
		}
		if (this.responseClass != null) {
			if (messageConverter.canRead(this.responseClass, contentType)) {
				if (logger.isDebugEnabled()) {
					logger.debug("Reading [" + this.responseClass.getName() + "] as \"" +
							contentType + "\" using [" + messageConverter + "]");
				}
				return (T) messageConverter.read((Class) this.responseClass, responseWrapper);
			}
		}
	}

	throw new RestClientException("Could not extract response: no suitable HttpMessageConverter found " +
			"for response type [" + this.responseType + "] and content type [" + contentType + "]");
}
 

@SuppressWarnings({ "unchecked", "rawtypes" })
private Object readWithMessageConverters(MethodParameter methodParam, HttpInputMessage inputMessage, Class<?> paramType)
		throws Exception {

	MediaType contentType = inputMessage.getHeaders().getContentType();
	if (contentType == null) {
		StringBuilder builder = new StringBuilder(ClassUtils.getShortName(methodParam.getParameterType()));
		String paramName = methodParam.getParameterName();
		if (paramName != null) {
			builder.append(' ');
			builder.append(paramName);
		}
		throw new HttpMediaTypeNotSupportedException(
				"Cannot extract parameter (" + builder.toString() + "): no Content-Type found");
	}

	List<MediaType> allSupportedMediaTypes = new ArrayList<MediaType>();
	if (this.messageConverters != null) {
		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((Class) paramType, inputMessage);
			}
		}
	}
	throw new HttpMediaTypeNotSupportedException(contentType, allSupportedMediaTypes);
}
 

@Override
@SuppressWarnings({"unchecked", "rawtypes"})
public T extractData(ClientHttpResponse response) throws IOException {
	MessageBodyClientHttpResponseWrapper responseWrapper = new MessageBodyClientHttpResponseWrapper(response);
	if (!responseWrapper.hasMessageBody() || responseWrapper.hasEmptyMessageBody()) {
		return null;
	}
	MediaType contentType = getContentType(responseWrapper);

	for (HttpMessageConverter<?> messageConverter : this.messageConverters) {
		if (messageConverter instanceof GenericHttpMessageConverter) {
			GenericHttpMessageConverter<?> genericMessageConverter = (GenericHttpMessageConverter<?>) messageConverter;
			if (genericMessageConverter.canRead(this.responseType, null, contentType)) {
				if (logger.isDebugEnabled()) {
					logger.debug("Reading [" + this.responseType + "] as \"" +
							contentType + "\" using [" + messageConverter + "]");
				}
				return (T) genericMessageConverter.read(this.responseType, null, responseWrapper);
			}
		}
		if (this.responseClass != null) {
			if (messageConverter.canRead(this.responseClass, contentType)) {
				if (logger.isDebugEnabled()) {
					logger.debug("Reading [" + this.responseClass.getName() + "] as \"" +
							contentType + "\" using [" + messageConverter + "]");
				}
				return (T) messageConverter.read((Class) this.responseClass, responseWrapper);
			}
		}
	}

	throw new RestClientException("Could not extract response: no suitable HttpMessageConverter found " +
			"for response type [" + this.responseType + "] and content type [" + contentType + "]");
}
 

@SuppressWarnings({ "unchecked", "rawtypes" })
private Object readWithMessageConverters(MethodParameter methodParam, HttpInputMessage inputMessage, Class<?> paramType)
		throws Exception {

	MediaType contentType = inputMessage.getHeaders().getContentType();
	if (contentType == null) {
		StringBuilder builder = new StringBuilder(ClassUtils.getShortName(methodParam.getParameterType()));
		String paramName = methodParam.getParameterName();
		if (paramName != null) {
			builder.append(' ');
			builder.append(paramName);
		}
		throw new HttpMediaTypeNotSupportedException(
				"Cannot extract parameter (" + builder.toString() + "): no Content-Type found");
	}

	List<MediaType> allSupportedMediaTypes = new ArrayList<MediaType>();
	if (this.messageConverters != null) {
		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((Class) paramType, inputMessage);
			}
		}
	}
	throw new HttpMediaTypeNotSupportedException(contentType, allSupportedMediaTypes);
}
 

@SuppressWarnings({ "rawtypes", "unchecked" })
@Override
public void handleError(ClientHttpResponse response) throws IOException {
    MediaType mediaType = response.getHeaders().getContentType();
    RestError error = null;
    for(HttpMessageConverter converter : converters) {
        if(converter.canRead(JsonRestError.class, mediaType)) {
            error = (RestError)converter.read(JsonRestError.class, response);
            break;
        }
    }
    throw new DCTMRestErrorException(response.getHeaders(), response.getStatusCode(), error);
}
 

@Override
@SuppressWarnings({ "unchecked", "rawtypes" })
protected Object doResolveArgumentFromNotificationMessage(JsonNode content,
		HttpInputMessage request, Class<?> parameterType) {
	if (!"Notification".equals(content.get("Type").asText())) {
		throw new IllegalArgumentException(
				"@NotificationMessage annotated parameters are only allowed for method that receive a notification message.");
	}

	MediaType mediaType = getMediaType(content);
	String messageContent = content.findPath("Message").asText();

	for (HttpMessageConverter<?> converter : this.messageConverter) {
		if (converter.canRead(parameterType, mediaType)) {
			try {
				return converter.read((Class) parameterType,
						new ByteArrayHttpInputMessage(messageContent, mediaType,
								request));
			}
			catch (Exception e) {
				throw new HttpMessageNotReadableException(
						"Error converting notification message with payload:"
								+ messageContent,
						e);
			}
		}
	}

	throw new HttpMessageNotReadableException(
			"Error converting notification message with payload:" + messageContent);
}
 

@Override
@SuppressWarnings({"unchecked", "rawtypes", "resource"})
public T extractData(ClientHttpResponse response) throws IOException {
	MessageBodyClientHttpResponseWrapper responseWrapper = new MessageBodyClientHttpResponseWrapper(response);
	if (!responseWrapper.hasMessageBody() || responseWrapper.hasEmptyMessageBody()) {
		return null;
	}
	MediaType contentType = getContentType(responseWrapper);

	try {
		for (HttpMessageConverter<?> messageConverter : this.messageConverters) {
			if (messageConverter instanceof GenericHttpMessageConverter) {
				GenericHttpMessageConverter<?> genericMessageConverter =
						(GenericHttpMessageConverter<?>) messageConverter;
				if (genericMessageConverter.canRead(this.responseType, null, contentType)) {
					if (logger.isDebugEnabled()) {
						ResolvableType resolvableType = ResolvableType.forType(this.responseType);
						logger.debug("Reading to [" + resolvableType + "]");
					}
					return (T) genericMessageConverter.read(this.responseType, null, responseWrapper);
				}
			}
			if (this.responseClass != null) {
				if (messageConverter.canRead(this.responseClass, contentType)) {
					if (logger.isDebugEnabled()) {
						String className = this.responseClass.getName();
						logger.debug("Reading to [" + className + "] as \"" + contentType + "\"");
					}
					return (T) messageConverter.read((Class) this.responseClass, responseWrapper);
				}
			}
		}
	}
	catch (IOException | HttpMessageNotReadableException ex) {
		throw new RestClientException("Error while extracting response for type [" +
				this.responseType + "] and content type [" + contentType + "]", ex);
	}

	throw new RestClientException("Could not extract response: no suitable HttpMessageConverter found " +
			"for response type [" + this.responseType + "] and content type [" + contentType + "]");
}
 

@Override
@SuppressWarnings({"unchecked", "rawtypes", "resource"})
public T extractData(ClientHttpResponse response) throws IOException {
	MessageBodyClientHttpResponseWrapper responseWrapper = new MessageBodyClientHttpResponseWrapper(response);
	if (!responseWrapper.hasMessageBody() || responseWrapper.hasEmptyMessageBody()) {
		return null;
	}
	MediaType contentType = getContentType(responseWrapper);

	try {
		for (HttpMessageConverter<?> messageConverter : this.messageConverters) {
			if (messageConverter instanceof GenericHttpMessageConverter) {
				GenericHttpMessageConverter<?> genericMessageConverter =
						(GenericHttpMessageConverter<?>) messageConverter;
				if (genericMessageConverter.canRead(this.responseType, null, contentType)) {
					if (logger.isDebugEnabled()) {
						ResolvableType resolvableType = ResolvableType.forType(this.responseType);
						logger.debug("Reading to [" + resolvableType + "]");
					}
					return (T) genericMessageConverter.read(this.responseType, null, responseWrapper);
				}
			}
			if (this.responseClass != null) {
				if (messageConverter.canRead(this.responseClass, contentType)) {
					if (logger.isDebugEnabled()) {
						String className = this.responseClass.getName();
						logger.debug("Reading to [" + className + "] as \"" + contentType + "\"");
					}
					return (T) messageConverter.read((Class) this.responseClass, responseWrapper);
				}
			}
		}
	}
	catch (IOException | HttpMessageNotReadableException ex) {
		throw new RestClientException("Error while extracting response for type [" +
				this.responseType + "] and content type [" + contentType + "]", ex);
	}

	throw new RestClientException("Could not extract response: no suitable HttpMessageConverter found " +
			"for response type [" + this.responseType + "] and content type [" + contentType + "]");
}