SpringBoot版本：2.1.2.RELEASE
1.maven
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.2.RELEASE</version>
</parent>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
2.主程序入口,两种方式
2.1. 初始化springApplication对象
listeners.starting(); EventPublishingRunListener
发布一个ApplicationStartingEvent事件
2.2. 准备环境变量 Environment
2.2.1.org.springframework.boot.SpringApplication#prepareEnvironment
org.springframework.boot.SpringApplication#getOrCreateEnvironment
new StandardServletEnvironment() ->new StandardEnvironment() ->new AbstractEnvironment()
public AbstractEnvironment() { this.propertyResolver = new PropertySourcesPropertyResolver(this.propertySources); this.customizePropertySources(this.propertySources); } #StandardServletEnvironment protected void customizePropertySources(MutablePropertySources propertySources) { propertySources.addLast(new StubPropertySource("servletConfigInitParams")); propertySources.addLast(new StubPropertySource("servletContextInitParams")); if (JndiLocatorDelegate.isDefaultJndiEnvironmentAvailable()) { propertySources.addLast(new JndiPropertySource("jndiProperties")); } super.customizePropertySources(propertySources); } #StandardEnvironment protected void customizePropertySources(MutablePropertySources propertySources) { propertySources.addLast(new MapPropertySource("systemProperties", this.getSystemProperties())); propertySources.addLast(new SystemEnvironmentPropertySource("systemEnvironment", this.getSystemEnvironment())); }
此时，environment中的propertySources包含servletConfigInitParams，servletContextInitParams，jndiProperties（存在的话,spring.properties中配置spring.jndi.ignore=true，且...待定），systemProperties，systemEnvironment
org.springframework.boot.SpringApplication#configureEnvironment
protected void configurePropertySources(ConfigurableEnvironment environment, String[] args) {
MutablePropertySources sources = environment.getPropertySources();
if (this.defaultProperties != null && !this.defaultProperties.isEmpty()) {
sources.addLast(new MapPropertySource("defaultProperties", this.defaultProperties));
}
if (this.addCommandLineProperties && args.length > 0) {
String name = "commandLineArgs";
if (sources.contains(name)) {
PropertySource<?> source = sources.get(name);
CompositePropertySource composite = new CompositePropertySource(name);
composite.addPropertySource(new SimpleCommandLinePropertySource("springApplicationCommandLineArgs", args));
composite.addPropertySource(source);
sources.replace(name, composite);
} else {
sources.addFirst(new SimpleCommandLinePropertySource(args));
}
}
}
org.springframework.boot.SpringApplicationRunListeners#environmentPrepared
发布一个ApplicationEnvironmentPreparedEvent
private PropertySource<?> propertySource = new MapPropertySource("configServerClient", Collections.singletonMap("spring.cloud.config.enabled", "false"));
public void onApplicationEvent(ApplicationEnvironmentPreparedEvent event) {
ConfigurableEnvironment environment = event.getEnvironment();
if (!environment.resolvePlaceholders("${spring.cloud.config.enabled:false}").equalsIgnoreCase("true") && !environment.getPropertySources().contains(this.propertySource.getName())) {
environment.getPropertySources().addLast(this.propertySource);
}
}
2.3. 初始化ApplicatonContext
org.springframework.boot.SpringApplication#createApplicationContext
创建一个AnnotationConfigApplicationContext
org.springframework.boot.SpringApplication#prepareContext
发布一个ApplicationContextInitializedEvent
org.springframework.boot.SpringApplication#refreshContext
发布一个ContextRefreshedContext，初始化所有的Bean
原文：https://www.cnblogs.com/Hleaves/p/10348779.html