Java tutorial
/* * Copyright 2002-2019 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.web.context.support; import javax.servlet.ServletConfig; import javax.servlet.ServletContext; import org.springframework.beans.factory.config.ConfigurableListableBeanFactory; import org.springframework.beans.factory.support.DefaultListableBeanFactory; import org.springframework.context.support.GenericApplicationContext; import org.springframework.core.env.ConfigurableEnvironment; import org.springframework.core.io.Resource; import org.springframework.core.io.support.ResourcePatternResolver; import org.springframework.lang.Nullable; import org.springframework.ui.context.Theme; import org.springframework.ui.context.ThemeSource; import org.springframework.ui.context.support.UiApplicationContextUtils; import org.springframework.util.Assert; import org.springframework.util.ObjectUtils; import org.springframework.util.StringUtils; import org.springframework.web.context.ConfigurableWebApplicationContext; import org.springframework.web.context.ConfigurableWebEnvironment; import org.springframework.web.context.ServletContextAware; /** * Subclass of {@link GenericApplicationContext}, suitable for web environments. * * <p>Implements {@link org.springframework.web.context.ConfigurableWebApplicationContext}, * but is not intended for declarative setup in {@code web.xml}. Instead, it is designed * for programmatic setup, for example for building nested contexts or for use within * {@link org.springframework.web.WebApplicationInitializer WebApplicationInitializers}. * * <p><b>If you intend to implement a WebApplicationContext that reads bean definitions * from configuration files, consider deriving from AbstractRefreshableWebApplicationContext, * reading the bean definitions in an implementation of the {@code loadBeanDefinitions} * method.</b> * * <p>Interprets resource paths as servlet context resources, i.e. as paths beneath * the web application root. Absolute paths, e.g. for files outside the web app root, * can be accessed via "file:" URLs, as implemented by AbstractApplicationContext. * * <p>In addition to the special beans detected by * {@link org.springframework.context.support.AbstractApplicationContext}, * this class detects a ThemeSource bean in the context, with the name "themeSource". * * @author Juergen Hoeller * @author Chris Beams * @since 1.2 */ public class GenericWebApplicationContext extends GenericApplicationContext implements ConfigurableWebApplicationContext, ThemeSource { @Nullable private ServletContext servletContext; @Nullable private ThemeSource themeSource; /** * Create a new GenericWebApplicationContext. * @see #setServletContext * @see #registerBeanDefinition * @see #refresh */ public GenericWebApplicationContext() { super(); } /** * Create a new GenericWebApplicationContext for the given ServletContext. * @param servletContext the ServletContext to run in * @see #registerBeanDefinition * @see #refresh */ public GenericWebApplicationContext(ServletContext servletContext) { this.servletContext = servletContext; } /** * Create a new GenericWebApplicationContext with the given DefaultListableBeanFactory. * @param beanFactory the DefaultListableBeanFactory instance to use for this context * @see #setServletContext * @see #registerBeanDefinition * @see #refresh */ public GenericWebApplicationContext(DefaultListableBeanFactory beanFactory) { super(beanFactory); } /** * Create a new GenericWebApplicationContext with the given DefaultListableBeanFactory. * @param beanFactory the DefaultListableBeanFactory instance to use for this context * @param servletContext the ServletContext to run in * @see #registerBeanDefinition * @see #refresh */ public GenericWebApplicationContext(DefaultListableBeanFactory beanFactory, ServletContext servletContext) { super(beanFactory); this.servletContext = servletContext; } /** * Set the ServletContext that this WebApplicationContext runs in. */ @Override public void setServletContext(@Nullable ServletContext servletContext) { this.servletContext = servletContext; } @Override @Nullable public ServletContext getServletContext() { return this.servletContext; } @Override public String getApplicationName() { return (this.servletContext != null ? this.servletContext.getContextPath() : ""); } /** * Create and return a new {@link StandardServletEnvironment}. */ @Override protected ConfigurableEnvironment createEnvironment() { return new StandardServletEnvironment(); } /** * Register ServletContextAwareProcessor. * @see ServletContextAwareProcessor */ @Override protected void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) { if (this.servletContext != null) { beanFactory.addBeanPostProcessor(new ServletContextAwareProcessor(this.servletContext)); beanFactory.ignoreDependencyInterface(ServletContextAware.class); } WebApplicationContextUtils.registerWebApplicationScopes(beanFactory, this.servletContext); WebApplicationContextUtils.registerEnvironmentBeans(beanFactory, this.servletContext); } /** * This implementation supports file paths beneath the root of the ServletContext. * @see ServletContextResource */ @Override protected Resource getResourceByPath(String path) { Assert.state(this.servletContext != null, "No ServletContext available"); return new ServletContextResource(this.servletContext, path); } /** * This implementation supports pattern matching in unexpanded WARs too. * @see ServletContextResourcePatternResolver */ @Override protected ResourcePatternResolver getResourcePatternResolver() { return new ServletContextResourcePatternResolver(this); } /** * Initialize the theme capability. */ @Override protected void onRefresh() { this.themeSource = UiApplicationContextUtils.initThemeSource(this); } /** * {@inheritDoc} * <p>Replace {@code Servlet}-related property sources. */ @Override protected void initPropertySources() { ConfigurableEnvironment env = getEnvironment(); if (env instanceof ConfigurableWebEnvironment) { ((ConfigurableWebEnvironment) env).initPropertySources(this.servletContext, null); } } @Override @Nullable public Theme getTheme(String themeName) { Assert.state(this.themeSource != null, "No ThemeSource available"); return this.themeSource.getTheme(themeName); } // --------------------------------------------------------------------- // Pseudo-implementation of ConfigurableWebApplicationContext // --------------------------------------------------------------------- @Override public void setServletConfig(@Nullable ServletConfig servletConfig) { // no-op } @Override @Nullable public ServletConfig getServletConfig() { throw new UnsupportedOperationException("GenericWebApplicationContext does not support getServletConfig()"); } @Override public void setNamespace(@Nullable String namespace) { // no-op } @Override @Nullable public String getNamespace() { throw new UnsupportedOperationException("GenericWebApplicationContext does not support getNamespace()"); } @Override public void setConfigLocation(String configLocation) { if (StringUtils.hasText(configLocation)) { throw new UnsupportedOperationException( "GenericWebApplicationContext does not support setConfigLocation(). " + "Do you still have an 'contextConfigLocations' init-param set?"); } } @Override public void setConfigLocations(String... configLocations) { if (!ObjectUtils.isEmpty(configLocations)) { throw new UnsupportedOperationException( "GenericWebApplicationContext does not support setConfigLocations(). " + "Do you still have an 'contextConfigLocations' init-param set?"); } } @Override public String[] getConfigLocations() { throw new UnsupportedOperationException( "GenericWebApplicationContext does not support getConfigLocations()"); } }