001/* 002 * Copyright 2002-2018 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.method.annotation; 018 019import java.util.Map; 020 021import org.springframework.core.MethodParameter; 022import org.springframework.web.bind.support.WebDataBinderFactory; 023import org.springframework.web.context.request.NativeWebRequest; 024import org.springframework.web.method.support.HandlerMethodArgumentResolver; 025import org.springframework.web.method.support.HandlerMethodReturnValueHandler; 026import org.springframework.web.method.support.ModelAndViewContainer; 027 028/** 029 * Resolves {@link Map} method arguments and handles {@link Map} return values. 030 * 031 * <p>A Map return value can be interpreted in more than one ways depending 032 * on the presence of annotations like {@code @ModelAttribute} or 033 * {@code @ResponseBody}. Therefore this handler should be configured after 034 * the handlers that support these annotations. 035 * 036 * @author Rossen Stoyanchev 037 * @since 3.1 038 */ 039public class MapMethodProcessor implements HandlerMethodArgumentResolver, HandlerMethodReturnValueHandler { 040 041 @Override 042 public boolean supportsParameter(MethodParameter parameter) { 043 return Map.class.isAssignableFrom(parameter.getParameterType()); 044 } 045 046 @Override 047 public Object resolveArgument(MethodParameter parameter, ModelAndViewContainer mavContainer, 048 NativeWebRequest webRequest, WebDataBinderFactory binderFactory) throws Exception { 049 050 return mavContainer.getModel(); 051 } 052 053 @Override 054 public boolean supportsReturnType(MethodParameter returnType) { 055 return Map.class.isAssignableFrom(returnType.getParameterType()); 056 } 057 058 @Override 059 @SuppressWarnings({"unchecked", "rawtypes"}) 060 public void handleReturnValue(Object returnValue, MethodParameter returnType, 061 ModelAndViewContainer mavContainer, NativeWebRequest webRequest) throws Exception { 062 063 if (returnValue == null) { 064 return; 065 } 066 else if (returnValue instanceof Map){ 067 mavContainer.addAllAttributes((Map) returnValue); 068 } 069 else { 070 // should not happen 071 throw new UnsupportedOperationException("Unexpected return type: " + 072 returnType.getParameterType().getName() + " in method: " + returnType.getMethod()); 073 } 074 } 075 076}