001/* 002 * Copyright 2002-2018 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.reactive.result.view.freemarker; 018 019import java.io.IOException; 020import java.util.List; 021 022import freemarker.cache.ClassTemplateLoader; 023import freemarker.cache.TemplateLoader; 024import freemarker.template.Configuration; 025import freemarker.template.TemplateException; 026 027import org.springframework.beans.factory.InitializingBean; 028import org.springframework.context.ResourceLoaderAware; 029import org.springframework.lang.Nullable; 030import org.springframework.ui.freemarker.FreeMarkerConfigurationFactory; 031import org.springframework.util.Assert; 032 033/** 034 * Configures FreeMarker for web usage via the "configLocation" and/or 035 * "freemarkerSettings" and/or "templateLoaderPath" properties. 036 * The simplest way to use this class is to specify just a "templateLoaderPath" 037 * (e.g. "classpath:templates"); you do not need any further configuration then. 038 * 039 * <p>This bean must be included in the application context of any application 040 * using {@link FreeMarkerView}. It exists purely to configure FreeMarker. 041 * It is not meant to be referenced by application components but just internally 042 * by {@code FreeMarkerView}. Implements {@link FreeMarkerConfig} to be found by 043 * {@code FreeMarkerView} without depending on the bean name of the configurer. 044 * 045 * <p>Note that you can also refer to a pre-configured FreeMarker Configuration 046 * instance via the "configuration" property. This allows to share a FreeMarker 047 * Configuration for web and email usage for example. 048 * 049 * <p>This configurer registers a template loader for this package, allowing to 050 * reference the "spring.ftl" macro library contained in this package: 051 * 052 * <pre class="code"> 053 * <#import "/spring.ftl" as spring/> 054 * <@spring.bind "person.age"/> 055 * age is ${spring.status.value}</pre> 056 * 057 * Note: Spring's FreeMarker support requires FreeMarker 2.3 or higher. 058 * 059 * @author Rossen Stoyanchev 060 * @since 5.0 061 */ 062public class FreeMarkerConfigurer extends FreeMarkerConfigurationFactory 063 implements FreeMarkerConfig, InitializingBean, ResourceLoaderAware { 064 065 @Nullable 066 private Configuration configuration; 067 068 069 public FreeMarkerConfigurer() { 070 setDefaultEncoding("UTF-8"); 071 } 072 073 074 /** 075 * Set a pre-configured Configuration to use for the FreeMarker web config, 076 * e.g. a shared one for web and email usage. If this is not set, 077 * FreeMarkerConfigurationFactory's properties (inherited by this class) 078 * have to be specified. 079 */ 080 public void setConfiguration(Configuration configuration) { 081 this.configuration = configuration; 082 } 083 084 085 /** 086 * Initialize FreeMarkerConfigurationFactory's Configuration 087 * if not overridden by a pre-configured FreeMarker Configuration. 088 * <p>Sets up a ClassTemplateLoader to use for loading Spring macros. 089 * @see #createConfiguration 090 * @see #setConfiguration 091 */ 092 @Override 093 public void afterPropertiesSet() throws IOException, TemplateException { 094 if (this.configuration == null) { 095 this.configuration = createConfiguration(); 096 } 097 } 098 099 /** 100 * This implementation registers an additional ClassTemplateLoader 101 * for the Spring-provided macros, added to the end of the list. 102 */ 103 @Override 104 protected void postProcessTemplateLoaders(List<TemplateLoader> templateLoaders) { 105 templateLoaders.add(new ClassTemplateLoader(FreeMarkerConfigurer.class, "")); 106 } 107 108 109 /** 110 * Return the Configuration object wrapped by this bean. 111 */ 112 @Override 113 public Configuration getConfiguration() { 114 Assert.state(this.configuration != null, "No Configuration available"); 115 return this.configuration; 116 } 117 118}