准备配置Bean

@Configuration
public class TestSpringApplication {
    static class Bean1 {
    }
    static class Bean2 {
    }
    static class Bean3 {
    }
    @Bean
    public Bean2 bean2() {
        return new Bean2();
    }
    @Bean
    public TomcatServletWebServerFactory tomcatServletWebServerFactory() {
        return new TomcatServletWebServerFactory();
    }
}

准备配置文件

测试加载BeanDefinition

测试推断应用类型

测试初始化器

测试主类推断

System.out.println("1. 从源中获取BeanDefinition");
// 配置类中获取
SpringApplication springApplication = new SpringApplication(TestSpringApplication.class);
// xml中获取
springApplication.setSources(CollUtil.newHashSet(
    "classpath:b01.xml"
));
System.out.println("2. 推断应用类型");
Method deduceFromClasspath = WebApplicationType.class.getDeclaredMethod("deduceFromClasspath");
deduceFromClasspath.setAccessible(true);
// 静态方法  不需要对象
System.out.println("\t应用类型:" + deduceFromClasspath.invoke(null));
System.out.println("3. 添加初始化器");
springApplication.addInitializers(applicationContext -> {
    if (applicationContext instanceof GenericApplicationContext) {
        GenericApplicationContext gac = (GenericApplicationContext) applicationContext;
        // 这个初始化器被调用时  会注册一个bean
        gac.registerBean("bean3", Bean3.class);
    }
});
System.out.println("4. 添加监听器");
springApplication.addListeners(event -> {
    System.out.println("\t事件为:" + event.getClass());
});
System.out.println("5. 主类推断");
Method deduceMainApplicationClass = SpringApplication.class.getDeclaredMethod("deduceMainApplicationClass");
deduceMainApplicationClass.setAccessible(true);
System.out.println("\t主类为:" + deduceMainApplicationClass.invoke(springApplication));
ConfigurableApplicationContext applicationContext = springApplication.run(args);
// 创建ApplicationContext
// 调用初始化器对ApplicationContext做扩展
// ApplicationContext.refresh
for (String beanDefinitionName : applicationContext.getBeanDefinitionNames()) {
    System.out.println("beanName:" + beanDefinitionName + " 来源=>" + applicationContext.getBeanFactory().getBeanDefinition(beanDefinitionName).getResourceDescription());
}
applicationContext.close();