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.context.support; 018 019import java.io.IOException; 020 021import javax.servlet.ServletException; 022import javax.servlet.http.HttpServlet; 023import javax.servlet.http.HttpServletRequest; 024import javax.servlet.http.HttpServletResponse; 025 026import org.springframework.context.i18n.LocaleContextHolder; 027import org.springframework.lang.Nullable; 028import org.springframework.util.Assert; 029import org.springframework.util.StringUtils; 030import org.springframework.web.HttpRequestHandler; 031import org.springframework.web.HttpRequestMethodNotSupportedException; 032import org.springframework.web.context.WebApplicationContext; 033 034/** 035 * Simple HttpServlet that delegates to an {@link HttpRequestHandler} bean defined 036 * in Spring's root web application context. The target bean name must match the 037 * HttpRequestHandlerServlet servlet-name as defined in {@code web.xml}. 038 * 039 * <p>This can for example be used to expose a single Spring remote exporter, 040 * such as {@link org.springframework.remoting.httpinvoker.HttpInvokerServiceExporter} 041 * or {@link org.springframework.remoting.caucho.HessianServiceExporter}, 042 * per HttpRequestHandlerServlet definition. This is a minimal alternative 043 * to defining remote exporters as beans in a DispatcherServlet context 044 * (with advanced mapping and interception facilities being available there). 045 * 046 * @author Juergen Hoeller 047 * @since 2.0 048 * @see org.springframework.web.HttpRequestHandler 049 * @see org.springframework.web.servlet.DispatcherServlet 050 */ 051@SuppressWarnings("serial") 052public class HttpRequestHandlerServlet extends HttpServlet { 053 054 @Nullable 055 private HttpRequestHandler target; 056 057 058 @Override 059 public void init() throws ServletException { 060 WebApplicationContext wac = WebApplicationContextUtils.getRequiredWebApplicationContext(getServletContext()); 061 this.target = wac.getBean(getServletName(), HttpRequestHandler.class); 062 } 063 064 065 @Override 066 protected void service(HttpServletRequest request, HttpServletResponse response) 067 throws ServletException, IOException { 068 069 Assert.state(this.target != null, "No HttpRequestHandler available"); 070 071 LocaleContextHolder.setLocale(request.getLocale()); 072 try { 073 this.target.handleRequest(request, response); 074 } 075 catch (HttpRequestMethodNotSupportedException ex) { 076 String[] supportedMethods = ex.getSupportedMethods(); 077 if (supportedMethods != null) { 078 response.setHeader("Allow", StringUtils.arrayToDelimitedString(supportedMethods, ", ")); 079 } 080 response.sendError(HttpServletResponse.SC_METHOD_NOT_ALLOWED, ex.getMessage()); 081 } 082 finally { 083 LocaleContextHolder.resetLocaleContext(); 084 } 085 } 086 087}