springboot启动入口

是整个流程启动的口子。

@SpringBootApplication
public class Starter {
    public static void main(String[] args) {
        SpringApplication.run(Starter.class,args);
        //new SpringApplication(Starter.class).run(args);
    }
}

在这里，主要有两点：

1，构造函数，构造函数主要是为了准备一些

2，run 是真正的核心流程，整个过程都在这里面；

构造函数

public SpringApplication(ResourceLoader resourceLoader, Class<?>... primarySources) {    this.resourceLoader = resourceLoader;    Assert.notNull(primarySources, "PrimarySources must not be null");    this.primarySources = new LinkedHashSet<>(Arrays.asList(primarySources));    //推断出应用程序是reactive、servlet，还是非web应用    this.webApplicationType = WebApplicationType.deduceFromClasspath();    setInitializers((Collection) getSpringFactoriesInstances(ApplicationContextInitializer.class));    setListeners((Collection) getSpringFactoriesInstances(ApplicationListener.class));    this.mainApplicationClass = deduceMainApplicationClass();  }