Java tutorial
/* * Copyright 2002-2018 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.http.client; import java.io.IOException; import org.springframework.http.HttpRequest; /** * Intercepts client-side HTTP requests. Implementations of this interface can be * {@linkplain org.springframework.web.client.RestTemplate#setInterceptors registered} * with the {@link org.springframework.web.client.RestTemplate RestTemplate}, * as to modify the outgoing {@link ClientHttpRequest} and/or the incoming * {@link ClientHttpResponse}. * * <p>The main entry point for interceptors is * {@link #intercept(HttpRequest, byte[], ClientHttpRequestExecution)}. * * @author Arjen Poutsma * @since 3.1 */ @FunctionalInterface public interface ClientHttpRequestInterceptor { /** * Intercept the given request, and return a response. The given * {@link ClientHttpRequestExecution} allows the interceptor to pass on the * request and response to the next entity in the chain. * <p>A typical implementation of this method would follow the following pattern: * <ol> * <li>Examine the {@linkplain HttpRequest request} and body</li> * <li>Optionally {@linkplain org.springframework.http.client.support.HttpRequestWrapper * wrap} the request to filter HTTP attributes.</li> * <li>Optionally modify the body of the request.</li> * <li><strong>Either</strong> * <ul> * <li>execute the request using * {@link ClientHttpRequestExecution#execute(org.springframework.http.HttpRequest, byte[])},</li> * <strong>or</strong> * <li>do not execute the request to block the execution altogether.</li> * </ul> * <li>Optionally wrap the response to filter HTTP attributes.</li> * </ol> * @param request the request, containing method, URI, and headers * @param body the body of the request * @param execution the request execution * @return the response * @throws IOException in case of I/O errors */ ClientHttpResponse intercept(HttpRequest request, byte[] body, ClientHttpRequestExecution execution) throws IOException; }