001/* 002 * Copyright 2002-2016 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.handler; 018 019import javax.servlet.http.HttpServletRequest; 020import javax.servlet.http.HttpServletResponse; 021 022import org.springframework.web.method.HandlerMethod; 023import org.springframework.web.servlet.ModelAndView; 024 025/** 026 * Abstract base class for 027 * {@link org.springframework.web.servlet.HandlerExceptionResolver HandlerExceptionResolver} 028 * implementations that support handling exceptions from handlers of type {@link HandlerMethod}. 029 * 030 * @author Rossen Stoyanchev 031 * @since 3.1 032 */ 033public abstract class AbstractHandlerMethodExceptionResolver extends AbstractHandlerExceptionResolver { 034 035 /** 036 * Checks if the handler is a {@link HandlerMethod} and then delegates to the 037 * base class implementation of {@code #shouldApplyTo(HttpServletRequest, Object)} 038 * passing the bean of the {@code HandlerMethod}. Otherwise returns {@code false}. 039 */ 040 @Override 041 protected boolean shouldApplyTo(HttpServletRequest request, Object handler) { 042 if (handler == null) { 043 return super.shouldApplyTo(request, handler); 044 } 045 else if (handler instanceof HandlerMethod) { 046 HandlerMethod handlerMethod = (HandlerMethod) handler; 047 handler = handlerMethod.getBean(); 048 return super.shouldApplyTo(request, handler); 049 } 050 else { 051 return false; 052 } 053 } 054 055 @Override 056 protected final ModelAndView doResolveException( 057 HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) { 058 059 return doResolveHandlerMethodException(request, response, (HandlerMethod) handler, ex); 060 } 061 062 /** 063 * Actually resolve the given exception that got thrown during on handler execution, 064 * returning a ModelAndView that represents a specific error page if appropriate. 065 * <p>May be overridden in subclasses, in order to apply specific exception checks. 066 * Note that this template method will be invoked <i>after</i> checking whether this 067 * resolved applies ("mappedHandlers" etc), so an implementation may simply proceed 068 * with its actual exception handling. 069 * @param request current HTTP request 070 * @param response current HTTP response 071 * @param handlerMethod the executed handler method, or {@code null} if none chosen at the time 072 * of the exception (for example, if multipart resolution failed) 073 * @param ex the exception that got thrown during handler execution 074 * @return a corresponding ModelAndView to forward to, or {@code null} for default processing 075 */ 076 protected abstract ModelAndView doResolveHandlerMethodException( 077 HttpServletRequest request, HttpServletResponse response, HandlerMethod handlerMethod, Exception ex); 078 079}