Java tutorial
/* * Copyright 2012-2019 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 * * https://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.boot; import org.springframework.util.ClassUtils; /** * An enumeration of possible types of web application. * * @author Andy Wilkinson * @author Brian Clozel * @since 2.0.0 */ public enum WebApplicationType { /** * The application should not run as a web application and should not start an * embedded web server. */ NONE, /** * The application should run as a servlet-based web application and should start an * embedded servlet web server. */ SERVLET, /** * The application should run as a reactive web application and should start an * embedded reactive web server. */ REACTIVE; private static final String[] SERVLET_INDICATOR_CLASSES = { "javax.servlet.Servlet", "org.springframework.web.context.ConfigurableWebApplicationContext" }; private static final String WEBMVC_INDICATOR_CLASS = "org.springframework.web.servlet.DispatcherServlet"; private static final String WEBFLUX_INDICATOR_CLASS = "org.springframework.web.reactive.DispatcherHandler"; private static final String JERSEY_INDICATOR_CLASS = "org.glassfish.jersey.servlet.ServletContainer"; private static final String SERVLET_APPLICATION_CONTEXT_CLASS = "org.springframework.web.context.WebApplicationContext"; private static final String REACTIVE_APPLICATION_CONTEXT_CLASS = "org.springframework.boot.web.reactive.context.ReactiveWebApplicationContext"; static WebApplicationType deduceFromClasspath() { if (ClassUtils.isPresent(WEBFLUX_INDICATOR_CLASS, null) && !ClassUtils.isPresent(WEBMVC_INDICATOR_CLASS, null) && !ClassUtils.isPresent(JERSEY_INDICATOR_CLASS, null)) { return WebApplicationType.REACTIVE; } for (String className : SERVLET_INDICATOR_CLASSES) { if (!ClassUtils.isPresent(className, null)) { return WebApplicationType.NONE; } } return WebApplicationType.SERVLET; } static WebApplicationType deduceFromApplicationContext(Class<?> applicationContextClass) { if (isAssignable(SERVLET_APPLICATION_CONTEXT_CLASS, applicationContextClass)) { return WebApplicationType.SERVLET; } if (isAssignable(REACTIVE_APPLICATION_CONTEXT_CLASS, applicationContextClass)) { return WebApplicationType.REACTIVE; } return WebApplicationType.NONE; } private static boolean isAssignable(String target, Class<?> type) { try { return ClassUtils.resolveClassName(target, null).isAssignableFrom(type); } catch (Throwable ex) { return false; } } }