001/* 002 * Copyright 2002-2019 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.ServletException; 020 021import org.springframework.core.MethodParameter; 022import org.springframework.lang.Nullable; 023import org.springframework.util.Assert; 024import org.springframework.web.bind.ServletRequestBindingException; 025import org.springframework.web.bind.annotation.SessionAttribute; 026import org.springframework.web.bind.annotation.ValueConstants; 027import org.springframework.web.context.request.NativeWebRequest; 028import org.springframework.web.context.request.RequestAttributes; 029import org.springframework.web.method.annotation.AbstractNamedValueMethodArgumentResolver; 030 031/** 032 * Resolves method arguments annotated with an @{@link SessionAttribute}. 033 * 034 * @author Rossen Stoyanchev 035 * @since 4.3 036 */ 037public class SessionAttributeMethodArgumentResolver extends AbstractNamedValueMethodArgumentResolver { 038 039 @Override 040 public boolean supportsParameter(MethodParameter parameter) { 041 return parameter.hasParameterAnnotation(SessionAttribute.class); 042 } 043 044 @Override 045 protected NamedValueInfo createNamedValueInfo(MethodParameter parameter) { 046 SessionAttribute ann = parameter.getParameterAnnotation(SessionAttribute.class); 047 Assert.state(ann != null, "No SessionAttribute annotation"); 048 return new NamedValueInfo(ann.name(), ann.required(), ValueConstants.DEFAULT_NONE); 049 } 050 051 @Override 052 @Nullable 053 protected Object resolveName(String name, MethodParameter parameter, NativeWebRequest request) { 054 return request.getAttribute(name, RequestAttributes.SCOPE_SESSION); 055 } 056 057 @Override 058 protected void handleMissingValue(String name, MethodParameter parameter) throws ServletException { 059 throw new ServletRequestBindingException("Missing session attribute '" + name + 060 "' of type " + parameter.getNestedParameterType().getSimpleName()); 061 } 062 063}