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/*
 * Copyright 2002-2020 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.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.web.client;

import java.io.IOException;
import java.lang.reflect.Type;
import java.net.URI;
import java.util.ArrayList;
import java.util.Collections;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.stream.Collectors;
import java.util.stream.Stream;

import org.springframework.core.ParameterizedTypeReference;
import org.springframework.http.HttpEntity;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpMethod;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.RequestEntity;
import org.springframework.http.ResponseEntity;
import org.springframework.http.client.ClientHttpRequest;
import org.springframework.http.client.ClientHttpRequestFactory;
import org.springframework.http.client.ClientHttpResponse;
import org.springframework.http.client.support.InterceptingHttpAccessor;
import org.springframework.http.converter.ByteArrayHttpMessageConverter;
import org.springframework.http.converter.GenericHttpMessageConverter;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.http.converter.ResourceHttpMessageConverter;
import org.springframework.http.converter.StringHttpMessageConverter;
import org.springframework.http.converter.cbor.MappingJackson2CborHttpMessageConverter;
import org.springframework.http.converter.feed.AtomFeedHttpMessageConverter;
import org.springframework.http.converter.feed.RssChannelHttpMessageConverter;
import org.springframework.http.converter.json.GsonHttpMessageConverter;
import org.springframework.http.converter.json.JsonbHttpMessageConverter;
import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;
import org.springframework.http.converter.smile.MappingJackson2SmileHttpMessageConverter;
import org.springframework.http.converter.support.AllEncompassingFormHttpMessageConverter;
import org.springframework.http.converter.xml.Jaxb2RootElementHttpMessageConverter;
import org.springframework.http.converter.xml.MappingJackson2XmlHttpMessageConverter;
import org.springframework.http.converter.xml.SourceHttpMessageConverter;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;
import org.springframework.web.util.DefaultUriBuilderFactory;
import org.springframework.web.util.DefaultUriBuilderFactory.EncodingMode;
import org.springframework.web.util.UriTemplateHandler;

/**
 * Synchronous client to perform HTTP requests, exposing a simple, template
 * method API over underlying HTTP client libraries such as the JDK
 * {@code HttpURLConnection}, Apache HttpComponents, and others.
 *
 * 

The RestTemplate offers templates for common scenarios by HTTP method, in * addition to the generalized {@code exchange} and {@code execute} methods that * support of less frequent cases. * *

NOTE: As of 5.0 this class is in maintenance mode, with * only minor requests for changes and bugs to be accepted going forward. Please, * consider using the {@code org.springframework.web.reactive.client.WebClient} * which has a more modern API and supports sync, async, and streaming scenarios. * * @author Arjen Poutsma * @author Brian Clozel * @author Roy Clarkson * @author Juergen Hoeller * @author Sam Brannen * @since 3.0 * @see HttpMessageConverter * @see RequestCallback * @see ResponseExtractor * @see ResponseErrorHandler */ public class RestTemplate extends InterceptingHttpAccessor implements RestOperations { private static final boolean romePresent; private static final boolean jaxb2Present; private static final boolean jackson2Present; private static final boolean jackson2XmlPresent; private static final boolean jackson2SmilePresent; private static final boolean jackson2CborPresent; private static final boolean gsonPresent; private static final boolean jsonbPresent; static { ClassLoader classLoader = RestTemplate.class.getClassLoader(); romePresent = ClassUtils.isPresent("com.rometools.rome.feed.WireFeed", classLoader); jaxb2Present = ClassUtils.isPresent("javax.xml.bind.Binder", classLoader); jackson2Present = ClassUtils.isPresent("com.fasterxml.jackson.databind.ObjectMapper", classLoader) && ClassUtils.isPresent("com.fasterxml.jackson.core.JsonGenerator", classLoader); jackson2XmlPresent = ClassUtils.isPresent("com.fasterxml.jackson.dataformat.xml.XmlMapper", classLoader); jackson2SmilePresent = ClassUtils.isPresent("com.fasterxml.jackson.dataformat.smile.SmileFactory", classLoader); jackson2CborPresent = ClassUtils.isPresent("com.fasterxml.jackson.dataformat.cbor.CBORFactory", classLoader); gsonPresent = ClassUtils.isPresent("com.google.gson.Gson", classLoader); jsonbPresent = ClassUtils.isPresent("javax.json.bind.Jsonb", classLoader); } private final List> messageConverters = new ArrayList<>(); private ResponseErrorHandler errorHandler = new DefaultResponseErrorHandler(); private UriTemplateHandler uriTemplateHandler; private final ResponseExtractor headersExtractor = new HeadersExtractor(); /** * Create a new instance of the {@link RestTemplate} using default settings. * Default {@link HttpMessageConverter HttpMessageConverters} are initialized. */ public RestTemplate() { this.messageConverters.add(new ByteArrayHttpMessageConverter()); this.messageConverters.add(new StringHttpMessageConverter()); this.messageConverters.add(new ResourceHttpMessageConverter(false)); try { this.messageConverters.add(new SourceHttpMessageConverter<>()); } catch (Error err) { // Ignore when no TransformerFactory implementation is available } this.messageConverters.add(new AllEncompassingFormHttpMessageConverter()); if (romePresent) { this.messageConverters.add(new AtomFeedHttpMessageConverter()); this.messageConverters.add(new RssChannelHttpMessageConverter()); } if (jackson2XmlPresent) { this.messageConverters.add(new MappingJackson2XmlHttpMessageConverter()); } else if (jaxb2Present) { this.messageConverters.add(new Jaxb2RootElementHttpMessageConverter()); } if (jackson2Present) { this.messageConverters.add(new MappingJackson2HttpMessageConverter()); } else if (gsonPresent) { this.messageConverters.add(new GsonHttpMessageConverter()); } else if (jsonbPresent) { this.messageConverters.add(new JsonbHttpMessageConverter()); } if (jackson2SmilePresent) { this.messageConverters.add(new MappingJackson2SmileHttpMessageConverter()); } if (jackson2CborPresent) { this.messageConverters.add(new MappingJackson2CborHttpMessageConverter()); } this.uriTemplateHandler = initUriTemplateHandler(); } /** * Create a new instance of the {@link RestTemplate} based on the given {@link ClientHttpRequestFactory}. * @param requestFactory the HTTP request factory to use * @see org.springframework.http.client.SimpleClientHttpRequestFactory * @see org.springframework.http.client.HttpComponentsClientHttpRequestFactory */ public RestTemplate(ClientHttpRequestFactory requestFactory) { this(); setRequestFactory(requestFactory); } /** * Create a new instance of the {@link RestTemplate} using the given list of * {@link HttpMessageConverter} to use. * @param messageConverters the list of {@link HttpMessageConverter} to use * @since 3.2.7 */ public RestTemplate(List> messageConverters) { validateConverters(messageConverters); this.messageConverters.addAll(messageConverters); this.uriTemplateHandler = initUriTemplateHandler(); } private static DefaultUriBuilderFactory initUriTemplateHandler() { DefaultUriBuilderFactory uriFactory = new DefaultUriBuilderFactory(); uriFactory.setEncodingMode(EncodingMode.URI_COMPONENT); // for backwards compatibility.. return uriFactory; } /** * Set the message body converters to use. *

These converters are used to convert from and to HTTP requests and responses. */ public void setMessageConverters(List> messageConverters) { validateConverters(messageConverters); // Take getMessageConverters() List as-is when passed in here if (this.messageConverters != messageConverters) { this.messageConverters.clear(); this.messageConverters.addAll(messageConverters); } } private void validateConverters(List> messageConverters) { Assert.notEmpty(messageConverters, "At least one HttpMessageConverter is required"); Assert.noNullElements(messageConverters, "The HttpMessageConverter list must not contain null elements"); } /** * Return the list of message body converters. *

The returned {@link List} is active and may get appended to. */ public List> getMessageConverters() { return this.messageConverters; } /** * Set the error handler. *

By default, RestTemplate uses a {@link DefaultResponseErrorHandler}. */ public void setErrorHandler(ResponseErrorHandler errorHandler) { Assert.notNull(errorHandler, "ResponseErrorHandler must not be null"); this.errorHandler = errorHandler; } /** * Return the error handler. */ public ResponseErrorHandler getErrorHandler() { return this.errorHandler; } /** * Configure default URI variable values. This is a shortcut for: *

	 * DefaultUriBuilderFactory factory = new DefaultUriBuilderFactory();
	 * handler.setDefaultUriVariables(...);
	 *
	 * RestTemplate restTemplate = new RestTemplate();
	 * restTemplate.setUriTemplateHandler(handler);
	 * 
* @param uriVars the default URI variable values * @since 4.3 */ @SuppressWarnings("deprecation") public void setDefaultUriVariables(Map uriVars) { if (this.uriTemplateHandler instanceof DefaultUriBuilderFactory) { ((DefaultUriBuilderFactory) this.uriTemplateHandler).setDefaultUriVariables(uriVars); } else if (this.uriTemplateHandler instanceof org.springframework.web.util.AbstractUriTemplateHandler) { ((org.springframework.web.util.AbstractUriTemplateHandler) this.uriTemplateHandler) .setDefaultUriVariables(uriVars); } else { throw new IllegalArgumentException( "This property is not supported with the configured UriTemplateHandler."); } } /** * Configure a strategy for expanding URI templates. *

By default, {@link DefaultUriBuilderFactory} is used and for * backwards compatibility, the encoding mode is set to * {@link EncodingMode#URI_COMPONENT URI_COMPONENT}. As of 5.0.8, prefer * using {@link EncodingMode#TEMPLATE_AND_VALUES TEMPLATE_AND_VALUES}. *

Note: in 5.0 the switch from * {@link org.springframework.web.util.DefaultUriTemplateHandler * DefaultUriTemplateHandler} (deprecated in 4.3), as the default to use, to * {@link DefaultUriBuilderFactory} brings in a different default for the * {@code parsePath} property (switching from false to true). * @param handler the URI template handler to use */ public void setUriTemplateHandler(UriTemplateHandler handler) { Assert.notNull(handler, "UriTemplateHandler must not be null"); this.uriTemplateHandler = handler; } /** * Return the configured URI template handler. */ public UriTemplateHandler getUriTemplateHandler() { return this.uriTemplateHandler; } // GET @Override @Nullable public T getForObject(String url, Class responseType, Object... uriVariables) throws RestClientException { RequestCallback requestCallback = acceptHeaderRequestCallback(responseType); HttpMessageConverterExtractor responseExtractor = new HttpMessageConverterExtractor<>(responseType, getMessageConverters(), logger); return execute(url, HttpMethod.GET, requestCallback, responseExtractor, uriVariables); } @Override @Nullable public T getForObject(String url, Class responseType, Map uriVariables) throws RestClientException { RequestCallback requestCallback = acceptHeaderRequestCallback(responseType); HttpMessageConverterExtractor responseExtractor = new HttpMessageConverterExtractor<>(responseType, getMessageConverters(), logger); return execute(url, HttpMethod.GET, requestCallback, responseExtractor, uriVariables); } @Override @Nullable public T getForObject(URI url, Class responseType) throws RestClientException { RequestCallback requestCallback = acceptHeaderRequestCallback(responseType); HttpMessageConverterExtractor responseExtractor = new HttpMessageConverterExtractor<>(responseType, getMessageConverters(), logger); return execute(url, HttpMethod.GET, requestCallback, responseExtractor); } @Override public ResponseEntity getForEntity(String url, Class responseType, Object... uriVariables) throws RestClientException { RequestCallback requestCallback = acceptHeaderRequestCallback(responseType); ResponseExtractor> responseExtractor = responseEntityExtractor(responseType); return nonNull(execute(url, HttpMethod.GET, requestCallback, responseExtractor, uriVariables)); } @Override public ResponseEntity getForEntity(String url, Class responseType, Map uriVariables) throws RestClientException { RequestCallback requestCallback = acceptHeaderRequestCallback(responseType); ResponseExtractor> responseExtractor = responseEntityExtractor(responseType); return nonNull(execute(url, HttpMethod.GET, requestCallback, responseExtractor, uriVariables)); } @Override public ResponseEntity getForEntity(URI url, Class responseType) throws RestClientException { RequestCallback requestCallback = acceptHeaderRequestCallback(responseType); ResponseExtractor> responseExtractor = responseEntityExtractor(responseType); return nonNull(execute(url, HttpMethod.GET, requestCallback, responseExtractor)); } // HEAD @Override public HttpHeaders headForHeaders(String url, Object... uriVariables) throws RestClientException { return nonNull(execute(url, HttpMethod.HEAD, null, headersExtractor(), uriVariables)); } @Override public HttpHeaders headForHeaders(String url, Map uriVariables) throws RestClientException { return nonNull(execute(url, HttpMethod.HEAD, null, headersExtractor(), uriVariables)); } @Override public HttpHeaders headForHeaders(URI url) throws RestClientException { return nonNull(execute(url, HttpMethod.HEAD, null, headersExtractor())); } // POST @Override @Nullable public URI postForLocation(String url, @Nullable Object request, Object... uriVariables) throws RestClientException { RequestCallback requestCallback = httpEntityCallback(request); HttpHeaders headers = execute(url, HttpMethod.POST, requestCallback, headersExtractor(), uriVariables); return (headers != null ? headers.getLocation() : null); } @Override @Nullable public URI postForLocation(String url, @Nullable Object request, Map uriVariables) throws RestClientException { RequestCallback requestCallback = httpEntityCallback(request); HttpHeaders headers = execute(url, HttpMethod.POST, requestCallback, headersExtractor(), uriVariables); return (headers != null ? headers.getLocation() : null); } @Override @Nullable public URI postForLocation(URI url, @Nullable Object request) throws RestClientException { RequestCallback requestCallback = httpEntityCallback(request); HttpHeaders headers = execute(url, HttpMethod.POST, requestCallback, headersExtractor()); return (headers != null ? headers.getLocation() : null); } @Override @Nullable public T postForObject(String url, @Nullable Object request, Class responseType, Object... uriVariables) throws RestClientException { RequestCallback requestCallback = httpEntityCallback(request, responseType); HttpMessageConverterExtractor responseExtractor = new HttpMessageConverterExtractor<>(responseType, getMessageConverters(), logger); return execute(url, HttpMethod.POST, requestCallback, responseExtractor, uriVariables); } @Override @Nullable public T postForObject(String url, @Nullable Object request, Class responseType, Map uriVariables) throws RestClientException { RequestCallback requestCallback = httpEntityCallback(request, responseType); HttpMessageConverterExtractor responseExtractor = new HttpMessageConverterExtractor<>(responseType, getMessageConverters(), logger); return execute(url, HttpMethod.POST, requestCallback, responseExtractor, uriVariables); } @Override @Nullable public T postForObject(URI url, @Nullable Object request, Class responseType) throws RestClientException { RequestCallback requestCallback = httpEntityCallback(request, responseType); HttpMessageConverterExtractor responseExtractor = new HttpMessageConverterExtractor<>(responseType, getMessageConverters()); return execute(url, HttpMethod.POST, requestCallback, responseExtractor); } @Override public ResponseEntity postForEntity(String url, @Nullable Object request, Class responseType, Object... uriVariables) throws RestClientException { RequestCallback requestCallback = httpEntityCallback(request, responseType); ResponseExtractor> responseExtractor = responseEntityExtractor(responseType); return nonNull(execute(url, HttpMethod.POST, requestCallback, responseExtractor, uriVariables)); } @Override public ResponseEntity postForEntity(String url, @Nullable Object request, Class responseType, Map uriVariables) throws RestClientException { RequestCallback requestCallback = httpEntityCallback(request, responseType); ResponseExtractor> responseExtractor = responseEntityExtractor(responseType); return nonNull(execute(url, HttpMethod.POST, requestCallback, responseExtractor, uriVariables)); } @Override public ResponseEntity postForEntity(URI url, @Nullable Object request, Class responseType) throws RestClientException { RequestCallback requestCallback = httpEntityCallback(request, responseType); ResponseExtractor> responseExtractor = responseEntityExtractor(responseType); return nonNull(execute(url, HttpMethod.POST, requestCallback, responseExtractor)); } // PUT @Override public void put(String url, @Nullable Object request, Object... uriVariables) throws RestClientException { RequestCallback requestCallback = httpEntityCallback(request); execute(url, HttpMethod.PUT, requestCallback, null, uriVariables); } @Override public void put(String url, @Nullable Object request, Map uriVariables) throws RestClientException { RequestCallback requestCallback = httpEntityCallback(request); execute(url, HttpMethod.PUT, requestCallback, null, uriVariables); } @Override public void put(URI url, @Nullable Object request) throws RestClientException { RequestCallback requestCallback = httpEntityCallback(request); execute(url, HttpMethod.PUT, requestCallback, null); } // PATCH @Override @Nullable public T patchForObject(String url, @Nullable Object request, Class responseType, Object... uriVariables) throws RestClientException { RequestCallback requestCallback = httpEntityCallback(request, responseType); HttpMessageConverterExtractor responseExtractor = new HttpMessageConverterExtractor<>(responseType, getMessageConverters(), logger); return execute(url, HttpMethod.PATCH, requestCallback, responseExtractor, uriVariables); } @Override @Nullable public T patchForObject(String url, @Nullable Object request, Class responseType, Map uriVariables) throws RestClientException { RequestCallback requestCallback = httpEntityCallback(request, responseType); HttpMessageConverterExtractor responseExtractor = new HttpMessageConverterExtractor<>(responseType, getMessageConverters(), logger); return execute(url, HttpMethod.PATCH, requestCallback, responseExtractor, uriVariables); } @Override @Nullable public T patchForObject(URI url, @Nullable Object request, Class responseType) throws RestClientException { RequestCallback requestCallback = httpEntityCallback(request, responseType); HttpMessageConverterExtractor responseExtractor = new HttpMessageConverterExtractor<>(responseType, getMessageConverters()); return execute(url, HttpMethod.PATCH, requestCallback, responseExtractor); } // DELETE @Override public void delete(String url, Object... uriVariables) throws RestClientException { execute(url, HttpMethod.DELETE, null, null, uriVariables); } @Override public void delete(String url, Map uriVariables) throws RestClientException { execute(url, HttpMethod.DELETE, null, null, uriVariables); } @Override public void delete(URI url) throws RestClientException { execute(url, HttpMethod.DELETE, null, null); } // OPTIONS @Override public Set optionsForAllow(String url, Object... uriVariables) throws RestClientException { ResponseExtractor headersExtractor = headersExtractor(); HttpHeaders headers = execute(url, HttpMethod.OPTIONS, null, headersExtractor, uriVariables); return (headers != null ? headers.getAllow() : Collections.emptySet()); } @Override public Set optionsForAllow(String url, Map uriVariables) throws RestClientException { ResponseExtractor headersExtractor = headersExtractor(); HttpHeaders headers = execute(url, HttpMethod.OPTIONS, null, headersExtractor, uriVariables); return (headers != null ? headers.getAllow() : Collections.emptySet()); } @Override public Set optionsForAllow(URI url) throws RestClientException { ResponseExtractor headersExtractor = headersExtractor(); HttpHeaders headers = execute(url, HttpMethod.OPTIONS, null, headersExtractor); return (headers != null ? headers.getAllow() : Collections.emptySet()); } // exchange @Override public ResponseEntity exchange(String url, HttpMethod method, @Nullable HttpEntity requestEntity, Class responseType, Object... uriVariables) throws RestClientException { RequestCallback requestCallback = httpEntityCallback(requestEntity, responseType); ResponseExtractor> responseExtractor = responseEntityExtractor(responseType); return nonNull(execute(url, method, requestCallback, responseExtractor, uriVariables)); } @Override public ResponseEntity exchange(String url, HttpMethod method, @Nullable HttpEntity requestEntity, Class responseType, Map uriVariables) throws RestClientException { RequestCallback requestCallback = httpEntityCallback(requestEntity, responseType); ResponseExtractor> responseExtractor = responseEntityExtractor(responseType); return nonNull(execute(url, method, requestCallback, responseExtractor, uriVariables)); } @Override public ResponseEntity exchange(URI url, HttpMethod method, @Nullable HttpEntity requestEntity, Class responseType) throws RestClientException { RequestCallback requestCallback = httpEntityCallback(requestEntity, responseType); ResponseExtractor> responseExtractor = responseEntityExtractor(responseType); return nonNull(execute(url, method, requestCallback, responseExtractor)); } @Override public ResponseEntity exchange(String url, HttpMethod method, @Nullable HttpEntity requestEntity, ParameterizedTypeReference responseType, Object... uriVariables) throws RestClientException { Type type = responseType.getType(); RequestCallback requestCallback = httpEntityCallback(requestEntity, type); ResponseExtractor> responseExtractor = responseEntityExtractor(type); return nonNull(execute(url, method, requestCallback, responseExtractor, uriVariables)); } @Override public ResponseEntity exchange(String url, HttpMethod method, @Nullable HttpEntity requestEntity, ParameterizedTypeReference responseType, Map uriVariables) throws RestClientException { Type type = responseType.getType(); RequestCallback requestCallback = httpEntityCallback(requestEntity, type); ResponseExtractor> responseExtractor = responseEntityExtractor(type); return nonNull(execute(url, method, requestCallback, responseExtractor, uriVariables)); } @Override public ResponseEntity exchange(URI url, HttpMethod method, @Nullable HttpEntity requestEntity, ParameterizedTypeReference responseType) throws RestClientException { Type type = responseType.getType(); RequestCallback requestCallback = httpEntityCallback(requestEntity, type); ResponseExtractor> responseExtractor = responseEntityExtractor(type); return nonNull(execute(url, method, requestCallback, responseExtractor)); } @Override public ResponseEntity exchange(RequestEntity requestEntity, Class responseType) throws RestClientException { RequestCallback requestCallback = httpEntityCallback(requestEntity, responseType); ResponseExtractor> responseExtractor = responseEntityExtractor(responseType); return nonNull(doExecute(requestEntity.getUrl(), requestEntity.getMethod(), requestCallback, responseExtractor)); } @Override public ResponseEntity exchange(RequestEntity requestEntity, ParameterizedTypeReference responseType) throws RestClientException { Type type = responseType.getType(); RequestCallback requestCallback = httpEntityCallback(requestEntity, type); ResponseExtractor> responseExtractor = responseEntityExtractor(type); return nonNull(doExecute(requestEntity.getUrl(), requestEntity.getMethod(), requestCallback, responseExtractor)); } // General execution /** * {@inheritDoc} *

To provide a {@code RequestCallback} or {@code ResponseExtractor} only, * but not both, consider using: *

    *
  • {@link #acceptHeaderRequestCallback(Class)} *
  • {@link #httpEntityCallback(Object)} *
  • {@link #httpEntityCallback(Object, Type)} *
  • {@link #responseEntityExtractor(Type)} *
*/ @Override @Nullable public T execute(String url, HttpMethod method, @Nullable RequestCallback requestCallback, @Nullable ResponseExtractor responseExtractor, Object... uriVariables) throws RestClientException { URI expanded = getUriTemplateHandler().expand(url, uriVariables); return doExecute(expanded, method, requestCallback, responseExtractor); } /** * {@inheritDoc} *

To provide a {@code RequestCallback} or {@code ResponseExtractor} only, * but not both, consider using: *

    *
  • {@link #acceptHeaderRequestCallback(Class)} *
  • {@link #httpEntityCallback(Object)} *
  • {@link #httpEntityCallback(Object, Type)} *
  • {@link #responseEntityExtractor(Type)} *
*/ @Override @Nullable public T execute(String url, HttpMethod method, @Nullable RequestCallback requestCallback, @Nullable ResponseExtractor responseExtractor, Map uriVariables) throws RestClientException { URI expanded = getUriTemplateHandler().expand(url, uriVariables); return doExecute(expanded, method, requestCallback, responseExtractor); } /** * {@inheritDoc} *

To provide a {@code RequestCallback} or {@code ResponseExtractor} only, * but not both, consider using: *

    *
  • {@link #acceptHeaderRequestCallback(Class)} *
  • {@link #httpEntityCallback(Object)} *
  • {@link #httpEntityCallback(Object, Type)} *
  • {@link #responseEntityExtractor(Type)} *
*/ @Override @Nullable public T execute(URI url, HttpMethod method, @Nullable RequestCallback requestCallback, @Nullable ResponseExtractor responseExtractor) throws RestClientException { return doExecute(url, method, requestCallback, responseExtractor); } /** * Execute the given method on the provided URI. *

The {@link ClientHttpRequest} is processed using the {@link RequestCallback}; * the response with the {@link ResponseExtractor}. * @param url the fully-expanded URL to connect to * @param method the HTTP method to execute (GET, POST, etc.) * @param requestCallback object that prepares the request (can be {@code null}) * @param responseExtractor object that extracts the return value from the response (can be {@code null}) * @return an arbitrary object, as returned by the {@link ResponseExtractor} */ @Nullable protected T doExecute(URI url, @Nullable HttpMethod method, @Nullable RequestCallback requestCallback, @Nullable ResponseExtractor responseExtractor) throws RestClientException { Assert.notNull(url, "URI is required"); Assert.notNull(method, "HttpMethod is required"); ClientHttpResponse response = null; try { ClientHttpRequest request = createRequest(url, method); if (requestCallback != null) { requestCallback.doWithRequest(request); } response = request.execute(); handleResponse(url, method, response); return (responseExtractor != null ? responseExtractor.extractData(response) : null); } catch (IOException ex) { String resource = url.toString(); String query = url.getRawQuery(); resource = (query != null ? resource.substring(0, resource.indexOf('?')) : resource); throw new ResourceAccessException("I/O error on " + method.name() + " request for \"" + resource + "\": " + ex.getMessage(), ex); } finally { if (response != null) { response.close(); } } } /** * Handle the given response, performing appropriate logging and * invoking the {@link ResponseErrorHandler} if necessary. *

Can be overridden in subclasses. * @param url the fully-expanded URL to connect to * @param method the HTTP method to execute (GET, POST, etc.) * @param response the resulting {@link ClientHttpResponse} * @throws IOException if propagated from {@link ResponseErrorHandler} * @since 4.1.6 * @see #setErrorHandler */ protected void handleResponse(URI url, HttpMethod method, ClientHttpResponse response) throws IOException { ResponseErrorHandler errorHandler = getErrorHandler(); boolean hasError = errorHandler.hasError(response); if (logger.isDebugEnabled()) { try { int code = response.getRawStatusCode(); HttpStatus status = HttpStatus.resolve(code); logger.debug("Response " + (status != null ? status : code)); } catch (IOException ex) { // ignore } } if (hasError) { errorHandler.handleError(url, method, response); } } /** * Return a {@code RequestCallback} that sets the request {@code Accept} * header based on the given response type, cross-checked against the * configured message converters. */ public RequestCallback acceptHeaderRequestCallback(Class responseType) { return new AcceptHeaderRequestCallback(responseType); } /** * Return a {@code RequestCallback} implementation that writes the given * object to the request stream. */ public RequestCallback httpEntityCallback(@Nullable Object requestBody) { return new HttpEntityRequestCallback(requestBody); } /** * Return a {@code RequestCallback} implementation that: *

    *
  1. Sets the request {@code Accept} header based on the given response * type, cross-checked against the configured message converters. *
  2. Writes the given object to the request stream. *
*/ public RequestCallback httpEntityCallback(@Nullable Object requestBody, Type responseType) { return new HttpEntityRequestCallback(requestBody, responseType); } /** * Return a {@code ResponseExtractor} that prepares a {@link ResponseEntity}. */ public ResponseExtractor> responseEntityExtractor(Type responseType) { return new ResponseEntityResponseExtractor<>(responseType); } /** * Return a response extractor for {@link HttpHeaders}. */ protected ResponseExtractor headersExtractor() { return this.headersExtractor; } private static T nonNull(@Nullable T result) { Assert.state(result != null, "No result"); return result; } /** * Request callback implementation that prepares the request's accept headers. */ private class AcceptHeaderRequestCallback implements RequestCallback { @Nullable private final Type responseType; public AcceptHeaderRequestCallback(@Nullable Type responseType) { this.responseType = responseType; } @Override public void doWithRequest(ClientHttpRequest request) throws IOException { if (this.responseType != null) { List allSupportedMediaTypes = getMessageConverters().stream() .filter(converter -> canReadResponse(this.responseType, converter)) .flatMap(this::getSupportedMediaTypes) .distinct() .sorted(MediaType.SPECIFICITY_COMPARATOR) .collect(Collectors.toList()); if (logger.isDebugEnabled()) { logger.debug("Accept=" + allSupportedMediaTypes); } request.getHeaders().setAccept(allSupportedMediaTypes); } } private boolean canReadResponse(Type responseType, HttpMessageConverter converter) { Class responseClass = (responseType instanceof Class ? (Class) responseType : null); if (responseClass != null) { return converter.canRead(responseClass, null); } else if (converter instanceof GenericHttpMessageConverter) { GenericHttpMessageConverter genericConverter = (GenericHttpMessageConverter) converter; return genericConverter.canRead(responseType, null, null); } return false; } private Stream getSupportedMediaTypes(HttpMessageConverter messageConverter) { return messageConverter.getSupportedMediaTypes() .stream() .map(mediaType -> { if (mediaType.getCharset() != null) { return new MediaType(mediaType.getType(), mediaType.getSubtype()); } return mediaType; }); } } /** * Request callback implementation that writes the given object to the request stream. */ private class HttpEntityRequestCallback extends AcceptHeaderRequestCallback { private final HttpEntity requestEntity; public HttpEntityRequestCallback(@Nullable Object requestBody) { this(requestBody, null); } public HttpEntityRequestCallback(@Nullable Object requestBody, @Nullable Type responseType) { super(responseType); if (requestBody instanceof HttpEntity) { this.requestEntity = (HttpEntity) requestBody; } else if (requestBody != null) { this.requestEntity = new HttpEntity<>(requestBody); } else { this.requestEntity = HttpEntity.EMPTY; } } @Override @SuppressWarnings("unchecked") public void doWithRequest(ClientHttpRequest httpRequest) throws IOException { super.doWithRequest(httpRequest); Object requestBody = this.requestEntity.getBody(); if (requestBody == null) { HttpHeaders httpHeaders = httpRequest.getHeaders(); HttpHeaders requestHeaders = this.requestEntity.getHeaders(); if (!requestHeaders.isEmpty()) { requestHeaders.forEach((key, values) -> httpHeaders.put(key, new LinkedList<>(values))); } if (httpHeaders.getContentLength() < 0) { httpHeaders.setContentLength(0L); } } else { Class requestBodyClass = requestBody.getClass(); Type requestBodyType = (this.requestEntity instanceof RequestEntity ? ((RequestEntity)this.requestEntity).getType() : requestBodyClass); HttpHeaders httpHeaders = httpRequest.getHeaders(); HttpHeaders requestHeaders = this.requestEntity.getHeaders(); MediaType requestContentType = requestHeaders.getContentType(); for (HttpMessageConverter messageConverter : getMessageConverters()) { if (messageConverter instanceof GenericHttpMessageConverter) { GenericHttpMessageConverter genericConverter = (GenericHttpMessageConverter) messageConverter; if (genericConverter.canWrite(requestBodyType, requestBodyClass, requestContentType)) { if (!requestHeaders.isEmpty()) { requestHeaders.forEach((key, values) -> httpHeaders.put(key, new LinkedList<>(values))); } logBody(requestBody, requestContentType, genericConverter); genericConverter.write(requestBody, requestBodyType, requestContentType, httpRequest); return; } } else if (messageConverter.canWrite(requestBodyClass, requestContentType)) { if (!requestHeaders.isEmpty()) { requestHeaders.forEach((key, values) -> httpHeaders.put(key, new LinkedList<>(values))); } logBody(requestBody, requestContentType, messageConverter); ((HttpMessageConverter) messageConverter).write( requestBody, requestContentType, httpRequest); return; } } String message = "No HttpMessageConverter for " + requestBodyClass.getName(); if (requestContentType != null) { message += " and content type \"" + requestContentType + "\""; } throw new RestClientException(message); } } private void logBody(Object body, @Nullable MediaType mediaType, HttpMessageConverter converter) { if (logger.isDebugEnabled()) { if (mediaType != null) { logger.debug("Writing [" + body + "] as \"" + mediaType + "\""); } else { logger.debug("Writing [" + body + "] with " + converter.getClass().getName()); } } } } /** * Response extractor for {@link HttpEntity}. */ private class ResponseEntityResponseExtractor implements ResponseExtractor> { @Nullable private final HttpMessageConverterExtractor delegate; public ResponseEntityResponseExtractor(@Nullable Type responseType) { if (responseType != null && Void.class != responseType) { this.delegate = new HttpMessageConverterExtractor<>(responseType, getMessageConverters(), logger); } else { this.delegate = null; } } @Override public ResponseEntity extractData(ClientHttpResponse response) throws IOException { if (this.delegate != null) { T body = this.delegate.extractData(response); return ResponseEntity.status(response.getRawStatusCode()).headers(response.getHeaders()).body(body); } else { return ResponseEntity.status(response.getRawStatusCode()).headers(response.getHeaders()).build(); } } } /** * Response extractor that extracts the response {@link HttpHeaders}. */ private static class HeadersExtractor implements ResponseExtractor { @Override public HttpHeaders extractData(ClientHttpResponse response) { return response.getHeaders(); } } }