001/* 002 * Copyright 2002-2014 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 java.io.OutputStream; 020import java.io.Writer; 021import java.lang.reflect.Method; 022import javax.servlet.ServletResponse; 023import javax.servlet.http.HttpServletResponse; 024 025import org.springframework.core.MethodParameter; 026import org.springframework.web.bind.support.WebDataBinderFactory; 027import org.springframework.web.context.request.NativeWebRequest; 028import org.springframework.web.method.support.HandlerMethodArgumentResolver; 029import org.springframework.web.method.support.ModelAndViewContainer; 030 031/** 032 * Resolves response-related method argument values of types: 033 * <ul> 034 * <li>{@link ServletResponse} 035 * <li>{@link OutputStream} 036 * <li>{@link Writer} 037 * </ul> 038 * 039 * @author Arjen Poutsma 040 * @author Rossen Stoyanchev 041 * @since 3.1 042 */ 043public class ServletResponseMethodArgumentResolver implements HandlerMethodArgumentResolver { 044 045 @Override 046 public boolean supportsParameter(MethodParameter parameter) { 047 Class<?> paramType = parameter.getParameterType(); 048 return (ServletResponse.class.isAssignableFrom(paramType) || 049 OutputStream.class.isAssignableFrom(paramType) || 050 Writer.class.isAssignableFrom(paramType)); 051 } 052 053 /** 054 * Set {@link ModelAndViewContainer#setRequestHandled(boolean)} to 055 * {@code false} to indicate that the method signature provides access 056 * to the response. If subsequently the underlying method returns 057 * {@code null}, the request is considered directly handled. 058 */ 059 @Override 060 public Object resolveArgument(MethodParameter parameter, ModelAndViewContainer mavContainer, 061 NativeWebRequest webRequest, WebDataBinderFactory binderFactory) throws Exception { 062 063 if (mavContainer != null) { 064 mavContainer.setRequestHandled(true); 065 } 066 067 HttpServletResponse response = webRequest.getNativeResponse(HttpServletResponse.class); 068 Class<?> paramType = parameter.getParameterType(); 069 070 if (ServletResponse.class.isAssignableFrom(paramType)) { 071 Object nativeResponse = webRequest.getNativeResponse(paramType); 072 if (nativeResponse == null) { 073 throw new IllegalStateException( 074 "Current response is not of type [" + paramType.getName() + "]: " + response); 075 } 076 return nativeResponse; 077 } 078 else if (OutputStream.class.isAssignableFrom(paramType)) { 079 return response.getOutputStream(); 080 } 081 else if (Writer.class.isAssignableFrom(paramType)) { 082 return response.getWriter(); 083 } 084 else { 085 // should not happen 086 Method method = parameter.getMethod(); 087 throw new UnsupportedOperationException("Unknown parameter type: " + paramType + " in method: " + method); 088 } 089 } 090 091}