Spring Boot启动过程

点击查看【processon】

public SpringApplication(ResourceLoader resourceLoader, Class<?>... primarySources) {
    //配置source
        this.resourceLoader = resourceLoader;
        Assert.notNull(primarySources, "PrimarySources must not be null");
        this.primarySources = new LinkedHashSet<>(Arrays.asList(primarySources));
    //配置是否为web环境
        this.webApplicationType = WebApplicationType.deduceFromClasspath();
    //创建初始化构造器
        setInitializers((Collection) getSpringFactoriesInstances(ApplicationContextInitializer.class));
    //创建应用监听
        setListeners((Collection) getSpringFactoriesInstances(ApplicationListener.class));
    //配置应用的主要方法所在类
        this.mainApplicationClass = deduceMainApplicationClass();
    }

• 配置是否为web环境 ```java /**

  • The application should not run as a web application and should not start an
  • embedded web server.
  • 该应用程序不应作为 Web 应用程序运行，也不应启动嵌入式网络服务器。

  • */ NONE,

    /**

  • The application should run as a servlet-based web application and should start an
  • embedded servlet web server.

  • 该应用程序应作为基于 servlet 的 Web 应用程序运行，并应启动嵌入式 servlet Web 服务器。 */ SERVLET,

    /**

  • The application should run as a reactive web application and should start an
  • embedded reactive web server.

  • 该应用程序应作为响应式 Web 应用程序运行，并应启动嵌入式响应式 Web 服务器。 */ REACTIVE;

    private static final String[] SERVLET_INDICATOR_CLASSES = { “javax.servlet.Servlet”,

     "org.springframework.web.context.ConfigurableWebApplicationContext" };

    private static final String WEBMVC_INDICATOR_CLASS = “org.springframework.web.servlet.DispatcherServlet”;

    private static final String WEBFLUX_INDICATOR_CLASS = “org.springframework.web.reactive.DispatcherHandler”;

    private static final String JERSEY_INDICATOR_CLASS = “org.glassfish.jersey.servlet.ServletContainer”;

    private static final String SERVLET_APPLICATION_CONTEXT_CLASS = “org.springframework.web.context.WebApplicationContext”;

    private static final String REACTIVE_APPLICATION_CONTEXT_CLASS = “org.springframework.boot.web.reactive.context.ReactiveWebApplicationContext”;

static WebApplicationType deduceFromClasspath() { if (ClassUtils.isPresent(WEBFLUX_INDICATOR_CLASS, null) && !ClassUtils.isPresent(WEBMVC_INDICATOR_CLASS, null) && !ClassUtils.isPresent(JERSEY_INDICATOR_CLASS, null)) { return WebApplicationType.REACTIVE; } for (String className : SERVLET_INDICATOR_CLASSES) { if (!ClassUtils.isPresent(className, null)) { return WebApplicationType.NONE; } } return WebApplicationType.SERVLET; } ```