001/* 002 * Copyright 2002-2017 the original author or authors. 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * https://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 017package org.springframework.web.servlet.mvc.method.annotation; 018 019import javax.servlet.http.HttpServletResponse; 020 021import org.springframework.core.MethodParameter; 022import org.springframework.http.HttpHeaders; 023import org.springframework.http.server.ServletServerHttpResponse; 024import org.springframework.util.Assert; 025import org.springframework.web.context.request.NativeWebRequest; 026import org.springframework.web.method.support.HandlerMethodReturnValueHandler; 027import org.springframework.web.method.support.ModelAndViewContainer; 028 029/** 030 * Handles {@link HttpHeaders} return values. 031 * 032 * @author Stephane Nicoll 033 * @since 4.0.1 034 */ 035public class HttpHeadersReturnValueHandler implements HandlerMethodReturnValueHandler { 036 037 @Override 038 public boolean supportsReturnType(MethodParameter returnType) { 039 return HttpHeaders.class.isAssignableFrom(returnType.getParameterType()); 040 } 041 042 @Override 043 @SuppressWarnings("resource") 044 public void handleReturnValue(Object returnValue, MethodParameter returnType, 045 ModelAndViewContainer mavContainer, NativeWebRequest webRequest) throws Exception { 046 047 mavContainer.setRequestHandled(true); 048 049 Assert.state(returnValue instanceof HttpHeaders, "HttpHeaders expected"); 050 HttpHeaders headers = (HttpHeaders) returnValue; 051 052 if (!headers.isEmpty()) { 053 HttpServletResponse servletResponse = webRequest.getNativeResponse(HttpServletResponse.class); 054 ServletServerHttpResponse outputMessage = new ServletServerHttpResponse(servletResponse); 055 outputMessage.getHeaders().putAll(headers); 056 outputMessage.getBody(); // flush headers 057 } 058 } 059 060}