SpringBoot常用配置简介 - 黑马程序员技术交流社区

一个简单的Spring.factories

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 # Bootstrap components

org.springframework.cloud.bootstrap.BootstrapConfiguration=\
org.springframework.cloud.config.server.bootstrap.ConfigServerBootstrapConfiguration

# Application listeners
org.springframework.context.ApplicationListener=\
org.springframework.cloud.config.server.bootstrap.ConfigServerBootstrapApplicationListener
# Autoconfiguration
org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
org.springframework.cloud.config.server.config.EncryptionAutoConfiguration,\
org.springframework.cloud.config.server.config.SingleEncryptorAutoConfiguration

BootstrapConfiguration简介
Spring.factories中的配置项， org.springframework.cloud.bootstrap.BootstrapConfiguration，会在Spring启动之前的准备上下文阶段将其加入到容器中。我们在介绍 @Configuration配置解析一文中曾详细解释Configuration中的解析。BootstrapConfiguration是在刷新（refresh）阶段将class作为预选的配置类@Configuration注入到容器中的，在@Configuration配置解析阶段会解析此class。

加载BootstrapConfiguration配置的类

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List<String> names = SpringFactoriesLoader
            .loadFactoryNames(BootstrapConfiguration.class, classLoader);
      for (String name : StringUtils.commaDelimitedListToStringArray(
            environment.getProperty("spring.cloud.bootstrap.sources", ""))) {
         names.add(name);
      }
      // TODO: is it possible or sensible to share a ResourceLoader?
      SpringApplicationBuilder builder = new SpringApplicationBuilder()
            .profiles(environment.getActiveProfiles()).bannerMode(Mode.OFF)
            .environment(bootstrapEnvironment)
            .properties("spring.application.name:" + configName)
            .registerShutdownHook(false).logStartupInfo(false).web(false);
      List<Class<?>> sources = new ArrayList<>();
      for (String name : names) {
         Class<?> cls = ClassUtils.resolveClassName(name, null);
         try {
            cls.getDeclaredAnnotations();
         }
         catch (Exception e) {
            continue;
         }
         sources.add(cls);
      }
      builder.sources(sources.toArray(new Class[sources.size()]));
      AnnotationAwareOrderComparator.sort(sources);
      final ConfigurableApplicationContext context = builder.run();

加载BootstrapConfiguration配置的类

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private void prepareContext(ConfigurableApplicationContext context,ConfigurableEnvironment environment, SpringApplicationRunListeners listeners,ApplicationArguments applicationArguments, Banner printedBanner) {
      context.setEnvironment(environment);
      postProcessApplicationContext(context);
      applyInitializers(context);
      listeners.contextPrepared(context);
      if (this.logStartupInfo) {
         logStartupInfo(context.getParent() == null);
         logStartupProfileInfo(context);
      }
// Add boot specific singleton beans
      context.getBeanFactory().registerSingleton("springApplicationArguments",
            applicationArguments);
      if (printedBanner != null) {
         context.getBeanFactory().registerSingleton("springBootBanner", printedBanner);
      }

      // Load the sources
      Set<Object> sources = getSources();//获取需要加载的class源
      Assert.notEmpty(sources, "Sources must not be empty");
      load(context, sources.toArray(new Object[sources.size()]));//加载class
      listeners.contextLoaded(context);
   }

ApplicationListener简介
org.springframework.context.ApplicationListener会在SpringBoot中几个典型事件产生后调用onApplicationEvent方法。详见Spring事件发布系统。

Autoconfiguration简介
org.springframework.boot.autoconfigure.EnableAutoConfiguration是SpringBoot中最常见配置，用于自动配置。只要有@EnableAutoConfiguration注解，该配置的所有类都会自动加载到Spring容器中。

没有智能的代码，源码面前了无秘密