接着上文，咱们进入 spring 的环境筹备办法中：
private ConfigurableEnvironment prepareEnvironment(SpringApplicationRunListeners listeners, ApplicationArguments applicationArguments) { // Create and configure the environment ConfigurableEnvironment environment = getOrCreateEnvironment(); configureEnvironment(environment, applicationArguments.getSourceArgs()); ConfigurationPropertySources.attach(environment); listeners.environmentPrepared(environment); bindToSpringApplication(environment) if (!this.isCustomEnvironment) { environment = new EnvironmentConverter(getClassLoader()).convertEnvironmentIfNecessary(environment, deduceEnvironmentClass()); } ConfigurationPropertySources.attach(environment); return environment; }其中 getOrCreateEnvironment 会依据以后的 webApplicationType 的类型来创立环境的类型，如果是 SERVLET 类型的话，会创立一个 StandardServletEnvironment 对象。这里的environmentPrepared 办法 ApplicationEnvironmentPreparedEvent 类型的事件。依据事件类型获取监听器，咱们来察看比拟重要的监听器：ConfigFileApplicationListener，在这个类型实现了咱们配置文件的解析。进入到其 onApplicationEvent 办法可知： 次要是获取到环境筹备的后置处理器（EnvironmentPostProcessor），并调用它们的 postProcessEnvironment 办法。值得注意的是 ConfigFileApplicationListener 本身也实现了EnvironmentPostProcessor 接口，也是 ConfigFileApplicationListener 实现了对配置文件的解析。
public void onApplicationEvent(ApplicationEvent event) { if (event instanceof ApplicationEnvironmentPreparedEvent) { onApplicationEnvironmentPreparedEvent((ApplicationEnvironmentPreparedEvent) event); } if (event instanceof ApplicationPreparedEvent) { onApplicationPreparedEvent(event); } } private void onApplicationEnvironmentPreparedEvent(ApplicationEnvironmentPreparedEvent event) { List<EnvironmentPostProcessor> postProcessors = loadPostProcessors(); postProcessors.add(this); AnnotationAwareOrderComparator.sort(postProcessors); for (EnvironmentPostProcessor postProcessor : postProcessors) { postProcessor.postProcessEnvironment(event.getEnvironment(), event.getSpringApplication()); } }跟进 ConfigFileApplicationListener 进入 load 办法：
void load() { FilteredPropertySource.apply(this.environment, DEFAULT_PROPERTIES, LOAD_FILTERED_PROPERTY, (defaultProperties) -> { this.profiles = new LinkedList<>(); this.processedProfiles = new LinkedList<>(); this.activatedProfiles = false; this.loaded = new LinkedHashMap<>(); initializeProfiles(); while (!this.profiles.isEmpty()) { Profile profile = this.profiles.poll(); if (isDefaultProfile(profile)) { addProfileToEnvironment(profile.getName()); } load(profile, this::getPositiveProfileFilter, addToLoaded(MutablePropertySources::addLast, false)); this.processedProfiles.add(profile); } load(null, this::getNegativeProfileFilter, addToLoaded(MutablePropertySources::addFirst, true)); addLoadedPropertySources(); applyActiveProfiles(defaultProperties); }); }持续进入这里的 load 办法
private void load(Profile profile, DocumentFilterFactory filterFactory, DocumentConsumer consumer) { getSearchLocations().forEach((location) -> { boolean isDirectory = location.endsWith("/"); Set<String> names = isDirectory ? getSearchNames() : NO_SEARCH_NAMES; names.forEach((name) -> load(location, name, profile, filterFactory, consumer)); }); }这俩的 getSearchLocations 办法是获取搜寻的门路，springboot 默认的门路为：DEFAULT_SEARCH_LOCATIONS = "classpath:/,classpath:/config/,file:./,file:./config/*/,file:./config/";获取多个搜寻门路之后，别离调用 load 办法。
private Set<String> getSearchLocations() { Set<String> locations = getSearchLocations(CONFIG_ADDITIONAL_LOCATION_PROPERTY); if (this.environment.containsProperty(CONFIG_LOCATION_PROPERTY)) { locations.addAll(getSearchLocations(CONFIG_LOCATION_PROPERTY)); } else { locations.addAll( asResolvedSet(ConfigFileApplicationListener.this.searchLocations, DEFAULT_SEARCH_LOCATIONS)); } return locations; }在这里的 load 办法里，有对应的 PropertiesPropertyResourceLoader 和 YamlPropertyResourceLoader 别离用于解析 (propertes、xml) 文件和 (yml、yaml) 文件。
到这里配置文件的解析曾经实现。