spring_boot查找配置文件源码分析

源码分析

1.找到配置文件

2.根据profile加载对应的文件或属性

3.把加载后的属性放到spring 容器中

spring boot项目的入口为main方法

加载配置的入口是有设计的。是观察者设计模式。

SpringApplication.run(SpringLogbackApplication.class, args);
new SpringApplication(primarySources)
setListeners((Collection) getSpringFactoriesInstances(ApplicationListener.class));
spring.factories
ConfigFileApplicationListener


public ConfigurableApplicationContext run(String... args)
ConfigurableEnvironment environment = prepareEnvironment(listeners, applicationArguments);
listeners.environmentPrepared(environment);
ConfigFileApplicationListener.onApplicationEvent(ApplicationEvent event) 
private void onApplicationEnvironmentPreparedEvent(ApplicationEnvironmentPreparedEvent event)
public void postProcessEnvironment(ConfigurableEnvironment environment, SpringApplication application)
protected void addPropertySources(ConfigurableEnvironment environment, ResourceLoader resourceLoader)
new Loader(environment, resourceLoader).load();

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());
					}
            // 加载配置文件
					load(profile, this::getPositiveProfileFilter,
							addToLoaded(MutablePropertySources::addLast, false));
					this.processedProfiles.add(profile);
				}
				load(null, this::getNegativeProfileFilter, addToLoaded(MutablePropertySources::addFirst, true));
				// 添加到spring 环境
          addLoadedPropertySources();
          // 设置启用的profile
				applyActiveProfiles(defaultProperties);
			});
}

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));
	});
}

这里涉及到3个值：去哪里找配置文件(location)、配置文件的名称是什么(getSearchNames)、不同环境(profile)

location位置： classpath:/, classpath:/config/, file:./, file:./config/ 优先级从低到高，最先加载file:./config/ 位置的配置文件；如果配置了spring.config.location属性则取这个属性的值。

配置文件的名字：默认值为：application;如果配置了spring.config.name属性则取改属性值。

环境为上面传进来的：自定义

private void load(String location, String name, Profile profile, DocumentFilterFactory filterFactory,
		DocumentConsumer consumer) {
	if (!StringUtils.hasText(name)) {
		for (PropertySourceLoader loader : this.propertySourceLoaders) {
			if (canLoadFileExtension(loader, location)) {
				load(loader, location, profile, filterFactory.getDocumentFilter(profile), consumer);
				return;
			}
		}
		throw new IllegalStateException("File extension of config file location '" + location
				+ "' is not known to any PropertySourceLoader. If the location is meant to reference "
				+ "a directory, it must end in '/'");
	}
	Set<String> processed = new HashSet<>();
	for (PropertySourceLoader loader : this.propertySourceLoaders) {
		for (String fileExtension : loader.getFileExtensions()) {
			if (processed.add(fileExtension)) {
				loadForFileExtension(loader, location + name, "." + fileExtension, profile, filterFactory,
						consumer);
			}
		}
	}
}