/*
 * Copyright 2002-2017 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.web.context.support;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.context.i18n.LocaleContextHolder;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.util.StringUtils;
import org.springframework.web.HttpRequestHandler;
import org.springframework.web.HttpRequestMethodNotSupportedException;
import org.springframework.web.context.WebApplicationContext;

Simple HttpServlet that delegates to an HttpRequestHandler bean defined in Spring's root web application context. The target bean name must match the HttpRequestHandlerServlet servlet-name as defined in web.xml.

This can for example be used to expose a single Spring remote exporter, such as HttpInvokerServiceExporter or HessianServiceExporter, per HttpRequestHandlerServlet definition. This is a minimal alternative to defining remote exporters as beans in a DispatcherServlet context (with advanced mapping and interception facilities being available there).

Author:Juergen Hoeller
See Also:
Since:2.0
/** * Simple HttpServlet that delegates to an {@link HttpRequestHandler} bean defined * in Spring's root web application context. The target bean name must match the * HttpRequestHandlerServlet servlet-name as defined in {@code web.xml}. * * <p>This can for example be used to expose a single Spring remote exporter, * such as {@link org.springframework.remoting.httpinvoker.HttpInvokerServiceExporter} * or {@link org.springframework.remoting.caucho.HessianServiceExporter}, * per HttpRequestHandlerServlet definition. This is a minimal alternative * to defining remote exporters as beans in a DispatcherServlet context * (with advanced mapping and interception facilities being available there). * * @author Juergen Hoeller * @since 2.0 * @see org.springframework.web.HttpRequestHandler * @see org.springframework.web.servlet.DispatcherServlet */
@SuppressWarnings("serial") public class HttpRequestHandlerServlet extends HttpServlet { @Nullable private HttpRequestHandler target; @Override public void init() throws ServletException { WebApplicationContext wac = WebApplicationContextUtils.getRequiredWebApplicationContext(getServletContext()); this.target = wac.getBean(getServletName(), HttpRequestHandler.class); } @Override protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { Assert.state(this.target != null, "No HttpRequestHandler available"); LocaleContextHolder.setLocale(request.getLocale()); try { this.target.handleRequest(request, response); } catch (HttpRequestMethodNotSupportedException ex) { String[] supportedMethods = ex.getSupportedMethods(); if (supportedMethods != null) { response.setHeader("Allow", StringUtils.arrayToDelimitedString(supportedMethods, ", ")); } response.sendError(HttpServletResponse.SC_METHOD_NOT_ALLOWED, ex.getMessage()); } finally { LocaleContextHolder.resetLocaleContext(); } } }